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Service Information 2014 Technik Introduction

911 GT3 (991)

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Important Notice: Some of the contents of this AfterSales Training brochure was originally written by Porsche AG for its rest-of-world English speaking market. The electronic text and graphic files were then imported by Porsche Cars N.A, Inc. and edited forcontent. Some equipment and technical data listed in this publication may not be applicable for our market. Specifications are subjectto change without notice.

We have attempted to render the text within this publication to American English as best as we could. We reserve the right tomake changes without notice.

© 2013 Porsche Cars North America, Inc. All Rights Reserved. Reproduction or translation in whole or in part is not permittedwithout written authorization from publisher. AfterSales Training Publications

Dr. Ing. h.c. F. Porsche AG is the owner of numerous trademarks, both registered and unregistered, including without limitationthe Porsche Crest®, Porsche®, Boxster®, Carrera®, Cayenne®, Cayman®, Panamera®, Speedster®, Spyder®, 918Spyder®, Tiptronic®, VarioCam®, PCM®, PDK®, 911®, 4S®, FOUR, UNCOMPROMISED.® and the model numbers and thedistinctive shapes of the Porsche automobiles such as, the federally registered 911 and Boxster automobiles. The third partytrademarks contained herein are the properties of their respective owners. Porsche Cars North America, Inc. believes the speci-fications to be correct at the time of printing. Specifications, performance standards, standard equipment, options, and otherelements shown are subject to change without notice. Some options may be unavailable when a car is built. Some vehicles maybe shown with non-U.S. equipment. The information contained herein is for internal use only by authorized Porsche dealers andauthorized users and cannot be copied or distributed. Porsche recommends seat belt usage and observance of traffic laws atall times.

Printed in the USA

Part Number - PNA 911 GT3 14 Edition - 9/13

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Foreword

The new 911 GT3 (991) is an uncompromising high-performance Sports Car for

the race circuit and a sporty companion in everyday life. No other vehicle mas-

ters the balancing act between sportiness and day-to-day usability better than the

911 GT3.

The standard Porsche Doppelkupplung (PDK) is an absolute innovative develop-

ment on the GT3, bringing the new GT3 even closer to its related model, the 911

GT3 Cup. For even greater agility and day-to-day usability, the new 911 GT3

comes with rear-axle steering, which helps to achieve more dynamic handling and

a smaller turning circle. For the first time, direct fuel injection (DFI) is used for the

on the GT3, ensuring lower fuel consumption and an even more spontaneous

response. To achieve the high engine speeds of 9,000 rpm, the valves are acti-

vated via valve levers.

2014 911 GT3 Section 0 9/16/13 6:39 AM Page v1

Note

The Service Information Technik is not intended as a basis for repairs or for diagno-

sis of technical problems. Information for repairs or diagnosis is available in the

PIWIS workshop manual. Please also refer to the information offered by the Porsche

Academy, which is being constantly expanded and updated.


1Engine 10Maintenance related information

Table of Contents

0 Maintenance related information 1General 1

Special features of individual assemblies 2

Vehicle inspection and maintenance for driving on race circuits 6

1 Engine 11.1 General 9

1.2 Technical data 10

1.3 Crankcase 10

1.4 Crankshaft 10

1.5 Belt drive 11

1.6 Pistons and connecting rods 11

1.7 Valve drive 12

1.8 Cylinder head 14

1.9 VarioCam 14

1.10 Oil supply 15

1.11 Dynamic engine mounts 18

2 DME engine electronics 192.1 General 19

2.2 Fuel system 20

2.3 Intake system 23

2.4 Mixture formation 27

2.5 Ignition system 29

2.6 Exhaust system 31

2.7 Additional DME functions 35

3 Power transmission 373.1 General 37

3.2 7-speed Porsche Doppelkupplung (PDK) 37

3.3 Paddle Neutral 39

3.4 Controls and displays 39

3.5 Gearshift strategies and shifting times 41

3.6 Porsche Torque Vectoring Plus (PTV Plus) 46

2DME engine electronics

3Power transmission


4 Chassis 474.1 General 47

4.2 Wheelbase and track widths 49

4.3 Front axle 50

4.4 Steering 51

4.5 Rear axle 52

4.6 Rear-axle steering 53

4.7 Brake system 56

4.8 Wheels and tires 59

4.9 Front axle lift system 62

4.10 Control systems 63

5 Body 655.1 General 65


5.3 Body-in-white 66

5.4 Aerodynamics 67

5.5 Exterior mirrors 70

6 Body – Exterior equipment 716.1 General 71

6.2 Front view 71

6.3 Side view 73

6.4 Rear view 74

7 Body – Interior equipment 777.1 General 77

7.2 Steering wheel 80

7.3 PDK selector lever 817Body equipment, interior

6Body equipment, exterior

4Chassis

5Body


8 Heating and air conditioning 838.1 2-zone automatic climate control 83

9 Electrics and electronics 859.1 Vehicle electrical system/energy management 85

9.2 Lighting 85

9.3 Instrument cluster 90

9.4 Infotainment 90

9.5 Glossary 94

Electrics and electronics 98Heating and air conditioning


911 GT3 (991)

1

0 Maintenance related Information

0.1 General information

The current country-specific maintenance specifications for the 911 GT3 can be

found in the PIWIS information system/maintenance schedule. For high-performance

driving on race circuits, the shorter maintenance intervals/ maintenance items

described in this section must be observed.

Up to a few years ago, the performance values that are possible on the race circuit

with the 911 GT3 could only be achieved using pure racing vehicles with racing

tires. Compared with on-road driving, high-performance driving on a race circuit

results in disproportionately higher stress on the vehicle and require closely sched-

uled maintenance and component replacement intervals. This includes checks, and

if necessary, the replacement of individual components whenever the vehicle has

been used on a race circuit, and also, the overhaul of complete assemblies after a

certain service life.

The 911 GT3 is a street legal high-performance Sports Car which can cover the

entire spectrum from pure day-to-day driving on public roads to high-performance

driving on the race circuit. However, this broad spectrum requires different

approaches to vehicle maintenance, depending on vehicle usage.

For example, the standard maintenance intervals can be perfectly adequate for a

“normal” load profile on public roads or on a race circuit, while additional checks

must always be carried out before use in the case of high-performance driving on a

race circuit. The following maintenance instructions explain the most important tech-

nical aspects that must be checked on the 911 GT3 in the event of high-perfor-

mance driving on a race circuit. The checks that must always be carried out before

using the vehicle are also listed.

The primary objective here is to ensure the proper technical condition of the vehicle

at all times, also for high-performance driving on the race circuit. Under certain cir-

cumstances, the vehicle warranty may be voided if these aspects are not taken into

consideration.

0Maintenance related information

0.1 General 1

0.2 Special features of individual

assemblies 2

0.3 Vehicle inspection and maintenance

for driving on race circuits 6

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911 GT3 (991)

2

0.2 Special features of individual assemblies

General

After finishing a session of high-performance driving on the race circuit, “cool-down

laps” must be driven in order to reduce the temperature level of the assemblies that

are subjected to particularly high thermal loads (brake system, engine) in a con-

trolled manner. Stopping the vehicle immediately would result in a further increase

in component temperatures due to the resultant stationary heating process. In

extreme cases, this could cause irreparable damage to individual components.

Certain motor sports equipment may not be legal on public roads, such as six-point

seat belts, emergency-off switches or door struts and A-pillar struts on the roll

cage. The same applies for the modifications to the chassis and aerodynamic com-

ponents described in the next sections.

The purpose of the following vehicle checks is to ensure the proper condition and

operational reliability of the vehicle for high-performance driving on a race circuit.

Due to the particular stress and strain on the vehicle during high-performance dri-

ving on the race circuit, a number of additional aspects must also be taken into con-

sideration. These are summarized for the most important assemblies.

Engine oil

An oil level of 3 segments above the minimum marking is recommended for optimal

engine operation, also for high-performance driving on the race circuit. When adding

engine oil, always keep in mind that the quantity difference between the minimum

and maximum markings is approximately 0.8 quarts (0.8 liters). Never overfill with

engine oil. In addition to the regular oil level check, the engine oil and oil filter must

be changed after 6,000 miles ( 10,000 km) of high-performance driving on the race

circuit.


A = Quantity difference of approximately 0.8 quarts (0.8 liters).

00_01_14


Brake system

The stresses exerted on the entire brake system during high-performance driving

on the race circuit are much higher than those produced during “normal” driving

because of the braking accelerations that can be achieved and the associated

higher component temperatures.

In addition, repeated hard braking in the ABS control range results in significantly

higher temperatures in the brake system than controlled braking just before the

ABS activation limit. The braking distance can actually be shorter if ABS is not acti-

vated. At the same time, the temperatures in the brake system and therefore the

wear and tear on the brake components remain lower.

During high-performance driving on the race circuit, all brake pads (inner and outer)

may exhibit brake pad wear characteristics that cannot be fully detected by the

standard brake pad wear indicator (“oblique wear”). Therefore, it is absolutely

essential to check the pad condition before and after driving on race circuits. The

standard brake pads are also optimally suited for high-performance driving on a

race circuit, which means that no special racing circuit pads are required.

While wear on standard brake discs in gray cast iron/aluminum composite design

can be checked in the conventional way, wear assessment of PCCB brake discs

must be carried out using a special electronic measuring device. This does not

involve “assessment of residual thickness”, but a Carboteq measurement, which

uses the current condition of the ceramic composite material as the wear criterion.

Details of the Carboteq measurement procedure can be found in the PIWIS informa-

tion system. The ventilation holes can become clogged with brake dust, particularly

on the gray cast-iron friction ring of the standard brake discs. These must be

cleaned if necessary.

Regular checking of the brake fluid (boiling point and fill level) is essential. Generally,

the brake fluid should not be more than 12 months old if the vehicle is driven on

race circuits. Before driving on race circuits, the dust boots on the brake calipers

and all brake hoses and lines must always be checked for possible damage and

replaced if necessary.

To ensure the necessary cooling of the brakes, special brake air spoilers and brake

air ducts are fitted on the front and rear axle in order to route sufficient cooling air

to the brake discs. These must be checked to ensure that they are in perfect condi-

tion and are secured correctly after every race track session. After finishing a ses-

sion of high-performance driving on the race circuit, “cool-down laps” must be dri-

ven in order to use the airstream to cool all brake components to a much lower

temperature level. The vehicle must never be stopped immediately after finishing a

“fast lap” because of the additional thermal stress (stationary heating process).

911 GT3 (991)

3


Checking PCCB wear 00_02_14

Brake air spoilers and brake 00_03_14air ducts


911 GT3 (991)

4

If driving is conducted in a particular style and if ambient temperatures are high, it

may be necessary when driving on a race circuit to compensate for the increase in

pressure for hot tires by letting out air. The general rule is that the specified tire

pressure should not be significantly exceeded, (maximum 7.3 psi/0.5 bar) even

when the tires have been driven until they are warm. For race circuit driving, differ-

ent pressures from those used for on-road driving can be set and monitored in the

Tire Pressure Monitoring (TPM) system. Letting air out of cold tires before driving on

a race circuit can damage the tire structure. Air must only be released from tires

that have been driven until they are warm.

The use of slick tires is not permitted because of the possible higher stresses for

chassis and body components. The use of wheels of different sizes (rim width, rim

offset, etc.) compared to standard wheels results in a change in the effective dis-

turbing force lever, for example. Widening of the track as a result of a lower rim off-

set on the front axle, in particular, can clearly impair vehicle handling and can signifi-

cantly affect driving performance at high speeds. The use of such wheels is there-

fore not permitted.

Other chassis-related topics

The chassis is adjustable with regard to track, camber, vehicle height and anti-roll

bar position. However, the basic factory setting is suitable both for driving on public

roads and for high-performance driving on race circuits. It also achieves a balanced

compromise between high maximum lateral acceleration and excellent controllability

on the race circuit. If the chassis setup is changed for driving on the race circuit, it

is important to keep in mind that setting higher camber values reduces straight-run-

ning stability while increasing tire wear, particularly on the inside shoulders of the

tires. When driving in the top speed range, increased camber values may result in

overloading of the tire structure.

Camber adjustments on the front axle must generally be made using the adjustable

supporting mounts. If an additional increase in camber is to be achieved by insert-

ing camber shims on the lower wishbone, there must always be sufficient thread

overlap (at least 22 mm) on the tie rod. Just like pure racing vehicles, the 911 GT3

is also very sensitive to small changes in the chassis settings. For optimum han-

dling, it is absolutely essential that suspension alignment is carried out correctly

with precise adherence to the nominal values and tolerances.


Tires 00_04_14

Camber adjustment via 00_05_14supporting mounts


Vehicle height must be checked during the race circuit inspection as the vehicle

height can indicate whether suspension alignment may be necessary. The thinking

behind this is that an unintentional change in vehicle height generally means that the

vehicle needs to be re-aligned. Depending on the individual stress and strain on the

vehicle, an additional suspension alignment may be necessary even if the vehicle

height is set correctly. Given the significant impact on handling, Porsche recom-

mends that all chassis settings are checked at regular intervals (vehicle alignment).

Despite regular checks and irrespective of the proper condition of all relevant chas-

sis components, certain components must be replaced after a specified mileage of

race track use. This applies to the central bolts and the wheel hubs, including wheel

bearings.

For information on the relevant replacement intervals:

Please refer to the “VEHICLE INSPECTION AND MAINTENANCE FOR DRIVING ON

RACE CIRCUITS” on the following pages.

Aerodynamic components

The aerodynamic stability of the vehicle is significantly affected by the front lip and

rear wing when travelling at high speeds. It is therefore necessary to check these

components for possible damage on a regular basis and to ensure that they are

secured correctly. The angle of attack of the rear wing can be adjusted according

to individual needs for driving on race circuits. As for the chassis, the basic factory

setting of the rear wing in terms of the aerodynamic overall balance of the vehicle

also achieves a balanced compromise between the downforce values on both axles

and the resultant drag on the race circuit.

For example, a steeper angle of attack not only causes more drag, but also moves

the aerodynamic balance towards the rear axle. This means less downforce on the

front axle and reduces any other possible side-effects (e.g. tendency of the vehicle

to understeer, etc.).

911 GT3 (991)

5


Central bolt and wheel hub 00_06_14

Rear wing adjustment 00_07_14


911 GT3 (991)

6

0.3 Vehicle inspection/maintenance for driving on race circuits

In addition to the regular maintenance tasks carried out as part of the standard

maintenance intervals, the following checks must always be carried out before use

in the case of high-performance driving on race circuits:

Engine oil

- Check engine-oil level.

After 6,000 miles (10,000 km) of high-performance driving on the race circuit (i.e. a

distance of approximately 2.5 x “24h Nürburgring race”):

- Change engine oil and oil filter.

Central wheel lock

Wheels removed

- Check that driving pins are installed securely.

- Check wheel mountings for damage.

- Check that the central bolt and locking mechanism move smoothly.

- Re-grease central lock.

After 6,000 miles (10,000 km) of high-performance driving on the race circuit (i.e.

a distance of approximately 2.5 x “24h Nürburgring race”):

- Replace all central bolts.

- Replace wheel hubs and wheel bearings on rear axle.

After 12,000 miles (20,000 km) of high-performance driving on the race circuit:

- Replace wheel hubs and wheel bearings on front axle.

Checking threaded connections for chassis setup

Front axle:

- Toe-in on tie rod.

- Camber adjustment via spring-strut supporting mount on body.

Rear axle:

- Toe-in on tie rod using eccentric screw.

- Eccentric screw for camber adjustment.

Front and rear axle:

- Camber adjustment within wishbone.

- Height adjustment on spring strut.

- Connecting link on anti-roll bar.

Wheel guidance joints

- Check joints for play and wear and replace if necessary.



Chassis setup

- Check vehicle height and align the suspension and make adjustments if neces-

sary.

Brakes

- Check wear/condition of pads and discs and replace them if necessary.

- Steel brake disc: Clean perforation holes if necessary.

- PCCB brake disc: Check wear dimension using electronic measuring device.

- Check dust boots on brake calipers for damage.

- Check brake lines and hoses for damage.

- Check brake fluid (boiling point, fill level).

- Check brake-disc air guides on both axles for correct seating and damage.

Tires

- Check tires for damage.

- Tire pressure: Take race circuit driving into consideration (tires that have been dri-

ven until they are warm).

Drive shafts

- Check boots on drive shafts for damage.

Aerodynamic components

- Check aerodynamic components for secure seating and damage.

911 GT3 (991)

7



1 Engine

1.1 General

The engine in the new 911 GT3 has been completely redesigned, adopting classic

911 GT3 components, such as dry sump lubrication with a separate engine oil tank,

high engine speed concept, titanium connecting rods and sports exhaust system,

as well as including totally new components, such as valve lever control for the

valves.

In addition, the new 911 GT3 engine also features direct fuel injection (DFI), an elec-

tronic demand-controlled oil pump and an enhanced high engine speed concept.

As a result, the engine delivers a maximum power output of 475 hp (350 kW) and

power output per liter of 125 hp/l with a displacement of 3.8 liters.

In addition to the mechanical and thermodynamic enhancements, it was also possi-

ble to significantly reduce the engine weight compared to the engine in the previous

model. The weight reduction of approximately 55 lbs. (25 kg) was primarily

achieved by using a new lightweight cylinder head, a new oil pan with integrated oil

pump module, a smaller engine oil tank, a plastic intake manifold and aluminum

camshaft controllers.

911 GT3 (991)

9

1Engine

1.1 General 9


1.3 Crankcase 10

1.4 Crankshaft 10

1.5 Belt drive 11

1.6 Pistons and connecting rods 11

1.7 Valve drive 12

1.8 Cylinder head 14

1.9 VarioCam 14

1.10 Oil supply 15

1.11 Dynamic engine mounts 18

01_01_14

The specifications in the PIWIS information

system and the instructions in section 0 of

this SIT must be observed when working

on the engine.


911 GT3 (991)

10

1.2 Technical data

No. of cylinders ................................................................................................6

Valves per cylinder ............................................................................................4

Displacement ......................................................................................3,799 cm3

Bore...................................................................................................102.0 mm

Stroke ..................................................................................................77.5 mm

Power .......................................................................................475 hp (350 kW)

at engine speed ..................................................................................8,250 rpm

Max. torque...........................................................................325 ft. lb. (440 Nm)

at engine speed ..................................................................................6,250 rpm

Compression ratio...................................................................................12.9 : 1

Intake valve lift ......................................................................................12.7 mm

Outlet valve lift ......................................................................................12.0 mm

Intake valve diameter ................................................................................42 mm

Exhaust valve diameter .............................................................................36 mm

Intake opens (1 mm) ....................................................................24.8° after TDC

Intake closes (1 mm)....................................................................84.9° after TDC

Exhaust opens (1 mm) ...............................................................73.2° before TDC

Exhaust closes (1 mm) ..............................................................18.5° before TDC

Governed speed..................................................................................9,000 rpm

Idle speed ............................................................................................740 ± 80

Engine weight.........................................................................374 lbs. (169.8 kg)

1.3 Crankcase

The crankcase in the 911 GT3 is based on that of the current 911 Carrera models

(991). Given the higher loads on the new 911 GT3, piston cooling, in particular, has

been improved and the oil supply for the bearing points on the crankshaft has been

enhanced.

1.4 Crankshaft

The crankshaft in the 911 GT3 has been especially adapted to the GT3-specific pis-

tons and connecting rods, but its basic design is the same as the crankshaft used in

the 911 Carrera (991).

1Engine

01_02_14


1.5 Belt drive

The auxiliary units are driven in the same way as the current 911 Carrera (991)

model line. The crankshaft pulley on the GT3 does not have a torsional vibration

damper and its diameter is smaller. This reduces the weight and rotating mass. The

smaller diameter means that the belt drive rotation speeds are adapted to the high

engine speeds.

1.6 Pistons and connecting rods

Like the previous models, the new 911 GT3 has forged aluminum pistons and

forged titanium connecting rods. The choice of material and forging technology

makes these highly stressed components especially lightweight and sturdy.

With these design features, these components meet the high thermal and mechani-

cal requirements (including maximum engine speed of 9,000 rpm).

911 GT3 (991)

11

1Engine

Piston and connecting rod 01_04_14

Piston 01_05_14

Belt pulley 01_02_14


911 GT3 (991)

12

1.7 Valve drive

The two timing chains on the GT3 are the same as the ones used on the current

911 Carrera models (991). The use of valve lever control for the valves is new,

combined with lightweight aluminum pistons, forged titanium connecting rods and,

hollow-drilled valves (intake and exhaust), allows for high engine rpm.

High engine speed concept

The high engine speed concept for increasing engine output and performance has

been further improved for the new 911 GT3. The maximum engine speed of the new

911 GT3 is 9,000 rpm, which is 500 rpm higher than the previous model (997 GT3

II: 8,500 rpm). This is possible thanks to the low moving masses of the crank and

valve drive. In addition to the low translational masses (pistons, connecting rods,

valves, valve levers), the rotating masses of the drive system have also been

reduced on the new 911 GT3. The reduced translational and rotating masses not

only ensure a low weight, but above all high engine speed dynamics.

1Engine

01_06_14


Valve lever control

Valve levers with hydraulic valve clearance compensation is new to the 911 GT3

engine. The intake and exhaust valves are controlled by valve levers. This technolo-

gy was taken from motor racing and is used to achieve high engine speeds as well

as power-oriented camshafts. The technical advantage of valve lever control is

above all the associated low moving masses.

1 - Intake camshaft 2 - Intake valve lever 3 - Hydraulic valve clearance compensating elements - Intake 4 - Intake valves 5 - Exhaust valves 6 - Hydraulic valve clearance compensating elements - Exhaust7 - Exhaust valve lever8 - Exhaust camshaft

911 GT3 (991)

13

1Engine

01_07_14

Valve lever with hydraulic 01_08_14

valve clearance compensating

element - Intake

Valve lever with hydraulic 01_09_14

valve clearance compensating

element - Exhaust


911 GT3 (991)

14

1.8 Cylinder head

The cylinder head is a complete in-house development for the new 911 GT3. To

achieve the high performance figures and engine speeds, the new cylinder head has

large intake and exhaust ports, large valves and unique valve control by way of valve

levers. The cooling system and oil supply for the cylinder head has also been

redesigned to meet the higher load requirements.

The cylinder heads also have an integrated drive for the direct fuel injection (DFI)

high-pressure pumps on each cylinder bank. There are therefore two radially driven

high-pressure pumps compared with one high-pressure pump driven axially by the

left exhaust camshaft on the 911 Carrera models.

1.9 VarioCam

Similar to the previous model, the intake and exhaust valves on the new 911 GT3

are controlled variably by way of VarioCam with continuous angle adjustment via

vane adjusters. This also permits realization of high torque and power figures. The

camshaft controllers are made of aluminum in order to reduce weight.

1Engine

01_10_14

01_11_14


1.10 Oil supply

Compared with the current 911 Carrera models, the new 911 GT3 features classic

dry-sump lubrication with a separate engine oil tank. This system ensures a reliable

oil supply for street and race circuit use.

Red - Pressure sideOrange - Intake side

Dry-sump lubrication

To allow dry-sump lubrication based on the new generation of engines (991), the oil

pan had to be completely redeveloped. The basis for this is the oil supply system

used in the current 911 Carrera models with four oil extraction pumps for the cylin-

der heads, an additional oil extraction pump in the oil pan and an oil pressure pump.

There are also two additional oil extraction points in the oil pan at the front and rear

so that the oil can be pumped out reliably into the separate oil tank even during

heavy acceleration and intensive braking phases.

911 GT3 (991)

15

1Engine

01_12_14


911 GT3 (991)

16

Oil windage tray

The new 911 GT3 also has an oil windage tray. This system originates from motor

racing and has been introduced as a new component. The oil windage tray consists

of a cover between the crankcase and oil pan with 18 individual openings (3 per

cylinder) with sickle-shaped blades. This system separates (“scrapes off”) the spray

oil, which is set in rotary motion by the crankshaft, at the sickle-shaped blades and

lets it drain back into the oil pan, particularly at high engine speeds. As a result,

there is less spray oil in the crankcase and the engine’s so-called “churning losses”

are reduced.

The oil-water heat exchanger and the oil filter are also located on the new oil pan.

Compared with the 911 Carrera engines where the oil-water heat exchanger and oil

filter are mounted above the engine block, their low position serves to further lower

the center of gravity of both the engine and the vehicle.

Engine oil tank

The separate engine oil tank was also newly developed. By changing it to a funnel-

shaped design, it was possible to reduce the oil fill volume of the new tank from 7.9

qts (7.5 l) (997 GT3 II) to 6.3 qts (6.0 l) compared with the previous model. This

reduces the vehicle weight by approximately 2.9 lbs (1.3 kg).

1Engine

Oil tank, oil windage tray, oil pump 01_13_14


Oil pump

In order to reduce the drive losses of auxiliary units as well as churning losses, the

new 911 GT3 is equipped with an electronic demand-controlled oil pump. With this

oil pump, the delivery pressure and volume are controlled for the entire engine map.

It also ensures demand-controlled lubrication and minimizes the energy consumption

of the oil pump.

1 - Variable pressure pump 2 - Suction pump (4 x) 3 - Control valve

In addition to the demand-controlled oil pump, the new 911 GT3 is fitted with not

just one (911 Carrera) but two piston oil spray nozzles, which are opened together,

depending on the temperature, load and engine speed. This allows more intensive

cooling of the pistons, which are subjected to high thermal loads.

911 GT3 (991)

17

1Engine

01_14_14

Oil spray nozzles 01_15_14


911 GT3 (991)

18

1.11 Dynamic engine mounts

In contrast to the previous model, the new 911 GT3 comes with dynamic engine

mounts as standard equipment. In order to enhance driving dynamics, the variable

engine mounts adjust their rigidity and damping automatically depending on the dri-

ving situation. This is still done using a magnetorheological liquid and an electrically

generated magnetic field. By applying a defined electric current, a magnetic field is

generated and the particles in the fluid are aligned to a greater or lesser extent.

This changes the viscosity of the fluid, thereby making the engine mounts harder or

softer.

Thanks to their variability, the dynamic engine mounts improve not only driving

dynamics, but also driving comfort by reducing the vibrations transmitted from the

entire drive unit to the body. The dynamic engine mounts have been enhanced and

the setup range between very sporty tuning and day-to-day usability has been fur-

ther increased.

The switching strategy of the dynamic engine mounts has been changed. Unlike the

previous model, the function maps are not changed using the PSM function buttons

(ESC OFF and ESC+TC OFF), but using the PASM button for the variable dampers.

The new 911 GT3 thus has sporty engine mounts when the PASM button is not

pressed and performance-oriented engine mounts when the PASM button is

pressed.

1Engine

01_16_14

ESC: Electronic Stability Control

TC: Traction Control


19

2DME Engine electronics

911 GT3 (991)2 DME engine electronics

2.1 General

The new 911 GT3 features direct fuel injection (DFI) for the first time. In contrast to

the conventional intake manifold injection system used on the previous GT3 models,

this technology offers advantages in terms of increased power and torque as well

as low fuel consumption and low CO2 emissions. The main reason for using this

injection technology for the new 911 GT3 was above all to increase engine power in

order to improve driving performance.

Development objectives:

• Reduce fuel consumption

• Reduce emissions

• More spontaneous response

Technical data - DME

DME control unit Bosch MED 17.1.11

Low-pressure fuel supply Demand-controlled in-tank fuel pump, with integrated

pressure regulator, maximum 79.75 psi (5.5 bar)

High-pressure fuel supply Two fuel high-pressure pumps with one quantity control

valve each

Fuel injection pressure 362.5 psi (25 bar) (idle speed) up to 2,900 psi

(200 bar) (full load)

Injector 6-hole injector

Tank capacity 16.9 gal. (64 l)

Fuel reserve 2.6 gal. (10 l)

Power 475 hp (350 kW)

at engine speed 8,250 rpm

Max. torque 325 ft. lb. (440 Nm)

at engine speed 6,250 rpm

Compression ratio 12.9 : 1

VarioCam intake camshaft 0 to 50° crank angle

VarioCam exhaust camshaft 0 to 30° crank angle

Idle speed 740 ± 80

Governed speed 9,000 rpm

2.1 General 19

2.2 Fuel system 20

2.3 Intake system 23

2.4 Mixture formation 27

2.5 Ignition system 29

2.6 Exhaust system 31

2.7 Additional DME functions 35


20


911 GT3 (991)2.2 Fuel system

Fuel quality

The engine is designed for unleaded fuel 93 octane ( ). Adaptation is performed by

the knock control if fuels with a fuel quality of at least 90 octane are used.

Fuel tank

The capacity of the standard fuel tank is 16.9 gal. (64 l). The fuel reserve is 2.6 gal.

(10 l). The fuel tank contains the electric fuel pump, the fuel filter (lifetime filter), the

fuel pressure regulator and the fuel-level sensor. The pump chamber is filled by a

sucking jet pump, which works according to the Venturi principle.

1 - Electric fuel pump2 - Sucking jet pump (Venturi nozzle) 3 - Fuel filter4 - Fuel pressure regulator, approximately 79.75 psi (5.5 bar) 5 - Fuel low-pressure line to the high-pressure pumps

Fuel low-pressure side

On the low-pressure side of the returnless fuel system (RF), fuel is supplied by way

of the electric fuel pump in the tank. The fuel low-pressure is maintained at maxi-

mum 79.75 psi (5.5 bar) using the fuel pressure regulator. The nominal values for

the fuel low-pressure, holding pressure and the fuel delivery rate can be found in the

PIWIS information system.

R+M2

02_01_14

The specifications and safety instructions

in the PIWIS information system Group 2

must be observed when working on the

fuel system.


21


911 GT3 (991)Control unit for electric fuel pump

The electric fuel pump is activated when opening the driver’s door, switching on the

ignition, starting the engine and while driving. Depending on the amount of fuel

required, the electrical current and thus the delivery rate of the electric fuel pump is

maintained at between approximately 5 and 15 A via a PWM signal from the DME

control unit.

The electrical current can be measured at the fuse for the electric fuel pump. The

control unit (see 02_02_14) for electric fuel pump flow control (1) and the NVLD

control unit (2) are installed under the battery tray (3) as on the 911 Carrera models

(991).

Fuel high-pressure side - direct fuel injection (DFI)

Compared with the direct fuel injection system used in the current 911 Carrera

models, the new 911 GT3 is fitted with its own separate injection system (Bosch

MED 17.1.11). Two high-pressure pumps are used to build up the fuel high-pres-

sure. The injection pressure of the multi-hole injectors is 362.5 psi (25 bar) (idle

speed) up to 2,900 psi (200 bar) (full load), making it much higher than on the 911

Carrera models (991). The fuel high-pressure is generated by two high-pressure

pumps - one on each cylinder bank - which are driven by the relevant intake

camshaft. This permits realization of the design requirements for VarioCam with

additional exhaust camshaft control.

1 - High-pressure pump 2 - Roller tappet 3 - Quantity control valve (for high-pressure control)

The high-pressure pump (see 02_04_14) is driven by a drive cam (1) on the intake

camshaft (2). This drive cam has a total of three lobes, resulting in three lifts per

camshaft revolution and for every two crankshaft revolutions.

Fuel high-pressure pump 02_03_14

02_02_14

02_04_14


22


911 GT3 (991)The fuel high-pressure is approximately 362.5 psi (25 bar) at idle speed and is regu-lated to maximum 2,900 psi (200 bar) at full load and high engine speed. Thisresults in a further increase in the amount of injected fuel and even finer atomizationof the fuel in the combustion chamber compared with the 911 Carrera models(1740 psi/120 bar). A high-pressure pump with a quantity control valve and a fuelrail with a high-pressure sensor are installed on each cylinder bank.

1 - Fuel high-pressure pump 2 - High-pressure line3 - High-pressure rail4 - 6-hole injectors 5 - Installation position of high-pressure sensor

6-hole injector

6-hole injectors are used. These injectors enable a high maximum flow for high

engine power in addition to sensitive injection for small flow quantities.

Fuel high-pressure system, left cylinder bank 02_05_14

6-hole injector 02_06_14


23


911 GT3 (991)2.3 Intake system

Ram air system

Unlike the 911 Carrera models (991), the 911 GT3 is equipped with a ram air sys-

tem. Ram air systems are intake systems in which the intake openings are arranged

in such a way that improved filling and thus an increase in engine power output can

be achieved as a result of the ram air produced by the moving vehicle.

The one-piece, scoop-shaped ram air box on the rear lid allows efficient intake of air

for the engine as well as improved supply of cooling air to the engine compartment.

Air routingThe flow- and resistance-optimized air intake system up to the large throttle valve

with a diameter of 86 mm was largely adopted from the current 911 generation

(991).

The illustration shows the air routing after the ram air system (1) via the air cleaner

housing (2) with sound openings (3) and two air-cleaner elements to the electronic

throttle.

02_07_14

02_08_14


24


911 GT3 (991)Intake system with resonance tube

The plastic resonance intake system is completely new. It is not only lighter than the

aluminum intake system used in the previous model, but is also larger and has

improved flow properties. The principle of using an intake system with a tuning flap

to achieve an optimum torque curve was adopted from the previous models.

1 - Resonance tube (air distributor)2 - Pressure sensor (intake manifold pressure) 3 - Intake manifold, left cylinder bank 4 - Intake manifold, right cylinder bank 5 - Electronic throttle flange

Pressure sensor for measuring engine load

A pressure sensor (2) in the intake system is used to measure the air flow (load

detection) in order to determine the required fuel injection quantity in the same way

as on the 911 Carrera (991). Compared with the hot-film mass air flow (MAF) sensor

used in the previous model, load detection via a pressure sensor offers lower flow

losses, higher accuracy with lower air flow and is less sensitive to soiling.

02_09_14


25


911 GT3 (991)Resonance tube

A switchable tuning flap installed after the electronic throttle in the resonance tube

is used to improve the engine torque. The length of the intake pipes and the design

of the resonance tube with its tuning flap are specially adapted for the 911 GT3.

The switching point of the tuning flap depends on the engine speed:

The tuning flap is closed at engine speeds of up to 7,400 rpm.

The tuning flap is opened at engine speeds of over 7,400 rpm.

1 - Resonance tube (air distributor)2 - Tuning flap 3 - Diaphragm cell (for closing the tuning flap)4 - Electronic throttle flange5 - Pressure sensor

02_10_14


26


911 GT3 (991)Vacuum system

On the 991 GT3, the vacuum at idle speed and in deceleration mode is taken from

the intake manifold. The vacuum is stored after the check valve in two vacuum

reservoirs installed under the intake manifold. The switching valves for activating the

individual functions/systems are also installed under the intake manifold.

1 - Check valve for vacuum supply2 - Large vacuum reservoir for activation of:

3 - Tuning flap4 - Exhaust flaps5 - Disc valve for PDK heat exchanger

6 - Small vacuum reservoir for activation of: 7 - Secondary-air injection

02_11_14


27


911 GT3 (991)2.4 Mixture formation

DFI fuel injection strategies

Engine start - cold: Triple injection

(1 x intake stroke, 2 x compression)

Engine start - warm: Single injection (in compression)

Warm-up phase: Catalytic converter warm-up:

Dual injection (1 x intake stroke, 1 x compression)

Remaining warm-up phase:

Single injection into the intake stroke

Idle speed

(at operating temp.): Single injection into the intake stroke (homogeneous)

Acceleration: Single injection into the intake stroke (Homogeneous)

Oxygen sensor closed-loop control

Two oxygen sensors are installed for each cylinder bank on the GT3. An LSU broad-

band oxygen sensor (1) upstream of the catalytic converter (3) and a two-point step

oxygen sensor (2) downstream of the catalytic converter.

LSU: Lambda Sensor Universal (broadband oxygen sensor)

LSF: Lambda Sensor Flat

Catalytic converter with oxygen sensors 02_12_14


28


911 GT3 (991)Tank leakage diagnosis

The new 911 GT3 uses the NVLD (Natural Vacuum Leak Detection) system for tank

leakage diagnosis. With this system, tank leakage diagnosis is performed as a pas-

sive long-term test when the vehicle is stationary for an extended period, which

means that no short test is now required for this purpose.

The components and function of the NVLD system with NVLD evaluation unit (elec-

tronic part with temperature sensor) and an NVLD module (pneumatic part) have

already been described in detail in the SIT, Group 2 for the 911 Carrera (991). The

evaluation unit is located under the battery tray. The pneumatic part is installed on

the carbon canister (Figure 02_14_14, position 1).

Active carbon filter (NVLD) 02_14_14

NVLD 02_15_14


29


911 GT3 (991)2.5 Ignition system

Components and functions of the ignition system:

• GT3-specific surface-gap spark plug with four ground electrodes

• Individual ignition coils with integrated driver (same as those used on the current

911 Carrera (991) models)

1 - Ignition coil2 - Spark plug

1 - Hall-effect sensor, intake camshaft2 - Spark-plug hole, cylinder 23 - Hall-effect sensor, exhaust camshaft

Ignition coil with spark plug 02_16_14

Hall-effect sensors, spark-plug holes 02_18_14

The safety instructions and vehicle-specific

specifications in the PIWIS information sys-

tem must be observed when working on the

ignition system.

The engine-specific maintenance intervals

for the spark plugs can be found in the

maintenance schedules in the PIWIS infor-

mation system.

Spark plug 02_17_14


30


911 GT3 (991)Hall-effect sensor

Given that the GT3 can adjust both the intake camshaft as well as the exhaust

camshaft variably via VarioCam, a Hall-effect sensor is required for each intake and

exhaust camshaft. The type of Hall-effect sensors used is the same as the sensors

used in the current 911 Carrera (991) model line.

Knock control

The GT3 uses two knock sensors for knock control, similar to the 911 Carrera

(991).

1 - Oil pressure and oil temperature sensor2 - Oil level sensor (at oil tank)3 - Fuel injector for cylinder 6 4 - Knock sensor (bank 2)

02_19_14


31


911 GT3 (991)2.6 Exhaust system

The sports exhaust system of the 911 GT3 is similar to the previous model. The

911 GT3 (991) also has high-performance manifolds, two close-coupled catalytic

converters integrated in the manifolds as well as two switchable front mufflers and

one rear muffler with two central tailpipes. The high-performance manifolds have

been redesigned and are now even more efficient thanks to the merging of the indi-

vidual tailpipes to achieve improved air flow characteristics.

Emission control/catalytic converter

A ceramic catalytic converter with 400 cells is installed at the end of the exhaust

manifold on each cylinder bank for emission control.

1 - High-performance manifold 2 - Broadband oxygen sensor (LSU) upstream of catalytic converter 3 - Catalytic converter 4 - Two-point step oxygen sensor (LSF) downstream of catalytic converter

Manifold with catalytic converter 02_20_14


32


911 GT3 (991)Secondary-air injection

To comply with country-specific emission standards, the 991 GT3 features sec-

ondary-air injection worldwide. With secondary-air injection, the heat that is released

during post-combustion at a low engine load during the first 30 seconds after a cold

start is used for targeted heating of the catalytic converters in order to reach the

conversion temperature quickly.

1 - Check valve for secondary air2 - Line to cylinder bank3 - Cylinder head on exhaust side

The electric secondary-air pump is located behind the intake manifold on cylinder

bank 1. When the secondary-air pump is activated, secondary air is routed via a

check valve (1) behind the exhaust valves into the cylinder head.

Secondary-air routing 02_21_14


33


911 GT3 (991)Exhaust gas flow

To achieve high engine power, the front mufflers can be activated and deactivated

by way of two map-controlled vacuum driven exhaust flaps. When these flaps are

closed, the exhaust gas is routed exclusively via the front muffler to the main muf-

fler. When the exhaust flaps open, this provides a direct passage to the main muf-

fler, resulting in a reduction in exhaust backpressure and a further increase in

engine power. The exhaust flaps are controlled according to the prevailing loads and

engine speeds.

1 - High-performance manifold2 - Catalytic converter3 - Front muffler4 - Diaphragm cell for switching the exhaust flap5 - Main muffler6 - Exhaust tailpipes7 - Underbody panelling

Air cleaner/catalytic converter/exhaust system 02_22_14


34


911 GT3 (991)Switchable exhaust flaps

Like its predecessor, the 911 GT3 (991) has a function for increasing torque in themiddle rpm range. This function is not activated by pressing a SPORT button as wasthe case for the previous model, but instead using the button with the twin tailpipesymbol (1) in the center console. When this button is pressed, the torque isincreased in the middle rpm range. The exhaust backpressure in the variableexhaust system is additionally reduced and the gas cycle is improved, resulting in anoticeable boost in torque in the rpm range between approximately. 3,000 and4,000 rpm. The torque levels are increased by between approximately 22 and 26 ft.lb. (30 and 35 Nm). The maximum torque of 325 ft. lb. (440 Nm) at 6,250 rpmremains unchanged.

The switching point of the exhaust flaps depends on the load and engine speed. Ason the 997 GT3 II, the switching point from closed to open at full throttle is 3,200rpm (exhaust flap button (1) pressed) and 4,000 rpm (exhaust flap button (1) notpressed).

Exhaust tailpipes

The outer diameter of the central tailpipes has been enlarged from 80 mm (997GT3 II) to 90 mm and their length has been adapted for the new rear apron.

Center console 02_23_14


35


911 GT3 (991)2.7 Additional DME functions

The DME control unit controls the following systems.

VarioCam

The DME control unit controls the variable valve control system for the intake andexhaust camshafts by way of VarioCam with continuous angle adjustment via vaneadjusters. This also ensures high torque and power figures for the new 911 GT3while at the same time taking into account exhaust emission laws that apply world-wide.

The adjustment range is:

0 to 50° crank angle on the intake side and 0 to 30° crank angle on the outlet side.

VarioCam 02_25_14


36


911 GT3 (991)Variable oil pump

Like the current 911 Carrera models (991), the 911 GT3 (991) has an electronic

demand-controlled oil pump. The delivery rate of the oil pump is pressure- and vol-

ume-controlled over the entire engine map.

It is controlled by the DME control unit, depending on the temperature, engine load

and engine speed.

Electric radiator fans

Like the 911 Carrera models (991), the 911 GT3 has two continuously controlled

electric radiator fans.

Engine compartment purge fan

The arrangement, function and control of the two electric, two-stage engine com-

partment purge fans is also comparable with the 911 Carrera models (991).

PDK disc valve

Depending on the temperature, the DME control unit activates and deactivates a

common disc valve on the PDK, which is responsible for cooling the oil in the gear

wheel set and the ATF oil.

02_26_14


37

3Power transmission

911 GT3 (991)3 Power transmission

3.1 General

The new 911 GT3 for the first time features the high-performance Porsche Dop-

pelkupplung (PDK). Its main advantage over a manual transmission is the possibility of

increasing performance thanks to faster gear changes without any interruption in

traction. To achieve this, the clutch on the engaged gear opens while the clutch on

the target gear closes at the same time. Compared with a manual transmission with

its consecutive “Disengage - Shift - Engage” gear changes, the PDK transmission -

with its simultaneous gear changes - not only eliminates any interruption in traction,

but is also much faster.

3.2 7-speed Porsche Doppelkupplung (PDK)

Compared with the Porsche Doppelkupplung (PDK) used on the current Porsche mod-

els, the main development objectives for the PDK transmission on the new 911 GT3

were as follows:

• Improving performance

• Reducing complexity

• Motor sports-oriented operating strategy

• More intensive interaction between vehicle and driver

• Enhancing emotionality

These objectives were achieved by a complete overhaul of the gearshift functions

and strategies as well as the transmission ratios and controls.

3.1 General 37

3.2 7-speed Porsche

Doppelkupplung (PDK) 37

3.3 Paddle Neutral 39

3.4 Controls and displays 39

3.5 Gearshift strategies and

shifting times 41

3.6 Porsche Torque Vectoring

Plus (PTV Plus) 46

03_01_14


38

3Power transmission

911 GT3 (991)Technical data

Transmission weight (wet, ready for installation) . . . . . . . . . . . .260 lbs. (117.5 kg)

Transmission weight (dry) . . . . . . . . . . . . . . . . . . . . . . . . . . . .243 lbs. (110.2 kg)

1st gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.750

2nd gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 2.381

3rd gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.720

4th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.344

5th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 1.114

6th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 0.957

7th gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 0.844

Reverse gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.417

Final-drive ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i = 3.973

Basic transmission

The Porsche Doppelkupplung (PDK) was modified significantly based on the current

911 Carrera models in order to adapt it to the performance-oriented objectives of the

new 911 GT3. These modifications include, shorter transmission ratios, shift paddles

with a shorter shift throw and a more precise one-touch function, an improved sporty

shift feeling with performance-oriented shift programs and significantly shorter shift

and response times. In addition, the shifting direction for manual gear changes on the

selector lever in the center console has been adapted to suit the requirements for

professional motor sports. As a result, upshifts “+” take place backwards and down-

shifts “–” take place forwards on the new 911 GT3.

The basic functional and mechanical features of the Porsche Doppelkupplung (PDK)

are the same as the tried-and-tested Porsche Doppelkupplung (PDK) used in the cur-

rent 911 generation (991). Improvements on the new 911 GT3 include the oil supply

and lubrication of the individual gear wheel sets (especially 5th and 7th gear) to

ensure a reliable oil supply even when driving on race circuits while taking into

account the much higher lateral acceleration potential of the new 911 GT3. The use

of lighter gear wheels and gear wheel sets has also resulted in a weight saving of

approximately 4 lbs. ( 1.8 kg).

The final-drive ratio and the complete gear wheel set with all gear ratios from 1st to

7th gear are new for the 911 GT3. To improve driving performance, the new 911

GT3 therefore has gear ratios that are much shorter than on the 911 Carrera models.

These can be up to 9% shorter than on the 911 Carrera S, depending on the gear.

In addition, 7th gear is very much a driving gear for reaching top speed and not an

additional gear (overdrive) for reducing engine speeds while driving with a high-com-

fort driving style as on the 911 Carrera models. Together with the 15% shorter final-

drive ratio, the new 911 GT3 also has much shorter total gear ratios.


39

3Power transmission

911 GT3 (991)3.3 Paddle Neutral

The “Paddle Neutral” function is based on the function of a clutch pedal on vehicles

with manual transmission. On the new 911 GT3, this decoupling function can also be

used for influencing driving dynamics individually, irrespective of the driving situation

and the engaged gear.

The Paddle Neutral function is activated by pulling and holding both shift paddles on

the steering wheel at the same time. This opens the clutches of the Porsche Dop-

pelkupplung (PDK) and interrupts the flow of power between the engine and the drive

system. When both shift paddles are released again, the clutch closes with lightning

speed if PSM is switched off (ESC+TC OFF) and there is a pulse-like resumption of

the flow of power between the engine and drive system. If PSM is switched on, the

clutch also closes quickly, but not in the same pulse-like way, when the paddles are

released at the same time. The engaged gear flashes on the gear indicator in the

instrument cluster to indicate that the Paddle Neutral function is activated.

The Paddle Neutral function essentially offers two advantages. First, if the vehicle

understeers in a curve (on a wet road, for example), this function allows the driver to

neutralize vehicle handling. The interruption in propulsion force on the rear axle pre-

vents further “sliding” over the front axle and allows the build-up of additional corner-

ing forces on the wheels on the front axle. This functional advantage therefore

ensures not only greater driving safety, but also improved driving performance as a

result of faster stabilization of the vehicle. The second advantage of the Paddle Neu-

tral function is due to the individual influencing of the driving dynamics through the

pulse-like build-up of propulsion force upon clutch engagement. During dynamic drive-

off acceleration in conjunction with the ESC+TC OFF function, for example, the

amount of slip on the wheels can therefore be controlled individually using the accel-

erator pedal.

3.4 Controls and displays

The sickle-shaped design and galvanized surface of the shift paddles on the GT3

SportDesign steering wheel are the same as on the current 911 Carrera models. The

motor sports-oriented shifting direction with upshifts “+” on the right shift paddle and

downshifts “–” on the left shift paddle is also the same as on the current 911 Carrera

models. The shift actuation and shift feeling of the paddles are completely new. The

switches on the paddles have been significantly modified for sporty shift actuation.

Shift travel was reduced by approx. 50% and the operating forces were adapted for a

sportier shift feeling. Overall, this change offers not only a sportier shift feeling with a

precise one-touch function and tangibly precise feedback, but also faster gear

changes as a result of shorter actuation travel. Selector lever and shift paddles 03_02_14


40

3Power transmission

911 GT3 (991)In addition to the shift paddles on the steering wheel, the PDK selector lever in the

center console was also adapted to the sporty character of the new 911 GT3. Com-

pared with the 911 Carrera models, the selector-lever knob is spherical and is based

on the design of a shift lever. In addition, the shape of the entire selector-lever handle

is different and the selector-lever knob has a black Alcantara finish.

The selector lever gate was also adapted for the new 911 GT3. To visually differenti-

ate the particularly sporty character of the Porsche Doppelkupplung (PDK), the selec-

tor lever gate has a central double stripe in black. The trim surround of the selector

lever gate was also adapted. In addition to being more purist with no additional selec-

tor-lever positions (P, R, N and D), the selector lever gate features a “GT3” logo and

on the left-hand side, the designations “+” and “–” in Red for manual gear selection.

The display of the selector-lever positions P, R, N and D on the selector-lever release

button and in the tachometer is unchanged.

The shifting direction for manual gear changes on the selector lever is completely

new. Unlike all shifting directions for Tiptronic and PDK transmissions used by

Porsche, the shifting direction used on the new 911 GT3 is based on professional

motor sports. As a result, upshifts “+” take place backwards and downshifts “–” take

place forwards. This shifting direction is used because of the ergonomic and physical

conditions involved in a gear change.

If the driver shifts down in gears while driving on the race circuit and braking sharply

coming into a bend, forward downshifting supports ergonomic gear changes in accor-

dance with the law relating to the mass moment of inertia. The same applies when

accelerating out of a bend. In this case, the mass moment of inertia supports back-

ward upshifting.

The PDK functions, including gear indicator, are displayed in the tachometer on the

instrument cluster as on the 911 Carrera models. The actuation direction of the man-

ual shift display “+” and “–” was modified due to the change in shifting direction spe-

cific to the GT3. The omission of the SPORT and SPORT PLUS function used on the

911 Carrera models and enhancement of the display strategy means that no PDK

functions are displayed in the SportDesign steering wheel on the new 911 GT3.


41

3Power transmission

911 GT3 (991)3.5 Gearshift strategies and shifting times

General

In addition to the short gear ratios and the short actuation travel of the shift paddles,

Porsche Doppelkupplung (PDK) is characterized above all by its unique gearshift

strategies and its short response and shifting times (including “lightning shifts”).

These characteristics ensure a performance-oriented gearshift behavior with particu-

larly sporty gear changes. The most important driving functions of the Porsche Dop-

pelkupplung (PDK) are based on the strategies of the current 911 Carrera models.

For differentiation and in order to adapt to the particularly sporty character of the

new 911 GT3, new functions have been introduced and modified functions and specif-

ic fine-tuning measures implemented.

The following main development objectives were taken into account here:

• Increasing performance

• Reducing complexity

• Improving interaction between driver and vehicle

• Enhancing emotionality

Increased performance is achieved with the following features:

• Lightning shifts with very short response and shifting times

• Performance-oriented adaptation of gear preselection

Reduced complexity is achieved with the following features:

• No special functions, such as Coasting, Auto Start Stop, ECO upshifts

• Two driving modes: SPORT (basic setting) and “PDK SPORT”

• Special functions, such as Launch Control, are available irrespective of driving

mode

• No kickdown

Increased interaction between driver and vehicle is achieved with the following fea-

tures:

• Selector-lever position “M” as an uncompromisingly manual shift function

• “M” with no automatic shift functions

• “M” with maximum acceptance of gearshift commands even during extreme engine

speed-oriented driving

• “Paddle Neutral” with additional function based on a conventional clutch pedal

Enhanced emotionality is achieved with the following features:

• Adaptation of the basic gearshift strategy to performance-oriented driving dynamics

without additional actuation of driving mode buttons

• Adaptation of the one-touch direction on the selector lever to motor sports

• Possibility of driving off with increased wheel slip with “Paddle Neutral”

• Possibility of influencing driving dynamics individually with “Paddle Neutral”

• No crawling without pressing the accelerator pedal


42

3Power transmission

911 GT3 (991)SPORT mode

The PDK transmission in the new 911 GT3 essentially has the two gearshift strate-

gies “SPORT” and “PDK SPORT”. Here, SPORT mode is the basic setting and is avail-

able immediately after starting the engine without pressing a button. PDK SPORT

mode is activated by pressing the “PDK SPORT” button in the center console. In this

mode, the shift sequences for changing gear are accomplished with torque increases

and maximum performance-oriented gearshift behavior.

Even at its basic setting, the new 911 GT3 has a sporty gearshift strategy. The basic

characteristics of this strategy are the same as the “SPORT” gearshift strategy of the

current 911 Carrera models. For the new 911 GT3, however, map-specific adjust-

ments were made to the gearshift strategy in order to meet the specific performance

requirements, including short gear ratios, as well as the unique engine and vehicle

characteristics. As a result, gear changes are always fast.

Based on the current 911 Carrera models, the shift sequences and shift points in

shift program “D” in the PDK used on the new 911 GT3 are also adapted and adjust-

ed to suit driver-specific handling. This means that the engine speeds are increased

early for changing gear, even for a moderately sporty driving style in performance-ori-

ented rpm ranges (> 3,500 rpm). Engine speeds are increased further for high-per-

formance driving. This is possible because the engine in the new 911 GT3 is excep-

tionally lively. For the driver, this gearshift strategy - even in the sporty basic setting in

“D” - ensures exceptionally good adaptation to the desired driving profile.

PDK SPORT mode

An even sportier PDK mode is activated by pressing the “PDK SPORT” button in the

center console. In this mode, the PDK has modified shift maps in selector-lever posi-

tion “D” which have been adapted to meet the requirements associated with driving

the vehicle on race circuits. As a result of the change in the shifting characteristic

curves, the shift map is moved towards higher engine speeds. This means that the

engaged gear is held longer and the next-higher gear is only selected at higher

engine speeds.

Race circuit tuning does not allow “back-adaptation” of the shift map for a moderately

sporty driving style in PDK SPORT mode. As a result, a higher tractive force potential

is available at all times, without changing gear. If the driver requests maximum accel-

eration (full throttle up to the rev limit) in PDK SPORT mode, engine interventions are

prevented during an upshift for a sporty, comfortable gear change. This means that

the engine is operated at full power even during the gear change and as a result, the

dynamic torque enhancement during gear changes is once again noticeably rein-

forced.


43

3Power transmission

911 GT3 (991)Shifting gears in M

Gears available

SPORT (basic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

PDK SPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

Automatic upshift and downshift in M

Partial load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .no

Full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .no

One-touch shifting (selector lever) . . . . . . . . . . . . . . . .front - /rear + (motor sport)

Shifting gears in D

Gearshifts

SPORT (basic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .performance-oriented

PDK SPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .performance-oriented

Adaptation to driving style

SPORT (basic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .yes

PDK SPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .yes

Moving off

From stationary (without accelerator pedal) . . . . . . . . . . . . . . . . . . . . .no crawling

Launch Control

SPORT (basic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .yes

PDK SPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .yes

ESC+ TC OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .active

With all these changes, the new 911 GT3 thus has a PDK transmission with a very

high shifting performance and exceptionally emotive gearshift and gear change func-

tions.

TC: Traction Control

ESC: Electronic Stability Control


44

3Power transmission

911 GT3 (991)Shifting performance

The new 911 GT3 has a much higher shifting performance mainly thanks to its much

shorter response times and shifting times as well as lightning shifts with much faster

gear changes. The diagram below shows the engine speed characteristic during gear

changes as a function of time. The red line in the diagram below represents the PDK

shift function of the 991 GT3, while the blue line represents the PDK shift function of

the 991 Carrera.

1 - PDK response time - 911 GT3 (991)

2 - PDK response time - 911 Carrera (991)

The difference between (2) and (1) shows how much the shifting time has been

reduced.

PDK comparison 03_03_14

3 - Shortening of the response time as a result of functional measures in the Porsche

Doppelkupplung (PDK) (“lightning shift”)

4 - Increase in engine speed gradient as a result of functional measures in the engine

electronics (DME) and optimized communication between engine and transmission

5 - 1st gear

6 - 2nd gear


45

3Power transmission

911 GT3 (991)Lightning shift

On the new 911 GT3, gear changes for a manually initiated upshift are accomplished

by way of a “lightning shift” with very short response and shifting times. This function

is initiated using a one-touch switch on the selector lever (M gate) or using the shift

paddles on the steering wheel. As a result, gear changes on the new 911 GT3 are

approximately 60% faster than on the 911 Carrera models. This is achieved thanks to

maximum performance in filling the clutch-specific hydraulic system and by activating

the overlap function between the closing and opening clutches at precisely the right

time.

The implementation of a lightning shift is the result of years of experience with the

Porsche Doppelkupplung (PDK) in various Porsche models. During this time Porsche

has been able to extensively analyze and precisely evaluate the intervention and

change behavior of the clutch system in many situations and under various condi-

tions. This has resulted in an enhanced control strategy for the complex clutch sys-

tem. By controlling the clutch change in a precise and highly dynamic way, it is possi-

ble to change gears much faster.

In addition, lightning shifts are implemented with a torque enhancement to improve

driving performance. The dynamic torque enhancement uses the momentum and

rotational energy that is present in the entire drive system during a gear change. In

this process, the rotational energy (mass moment of inertia), which is stored primarily

in the crankshaft, clutch module and gear wheel sets, is decelerated strongly while

changing gear. This causes a brief additional torque boost in the drive system and

allows a further improvement in the acceleration potential. The actual gear change

occurs with high engine speed dynamics and a highly dynamic adaptation of the

engine speed to the newly selected gear. The short synchronization times are in an

order of magnitude that was previously reserved for motor sports.

Gear change

The new 911 GT3 has very short response and shifting times, which are clearly

noticeable and help to enhance a sporty and emotive gear change. The engine fades

out and in again at lightning speed during a full-throttle upshift for enhanced acoustic

emotionality when changing gear. The lightning fade-out occurs when the gear

change is initiated. Compared with its driving dynamics competitors, the new 911

GT3 allows gear changing without interruption in traction. The competitor vehicles

with fast response times pay for acoustic emotionality with engine fade-out that inter-

rupts traction and impacts negatively on vehicle acceleration.

With Porsche Doppelkupplung (PDK), fast gear changes without interruption in trac-

tion are achieved by precisely fine-tuning all gearshift and gear change functions. The

specific characteristics of the PDK in the new 911 GT3 make it a particularly sporty

model with driving dynamics-oriented and performance-oriented shift functions as well

as emotional gear changes.


46

3Power transmission

911 GT3 (991)Launch Control

Like the current 911 Carrera models with Porsche Doppelkupplung (PDK), the new

911 GT3 also features the driving dynamics-oriented drive-off function “Launch Con-

trol” for maximum acceleration from standstill. Compared with these models, this

function on the new 911 GT3 can be activated at any time without pressing any other

buttons or switches. Readiness for an accelerated start is indicated in the tachometer

on the instrument cluster as on the 911 Carrera models.

3.6 Porsche Torque Vectoring Plus (PTV Plus)

The new 911 GT3 features Porsche Torque Vectoring Plus as standard. The system

includes an electronically regulated, fully variable rear differential lock with selective

braking interventions on the rear left or rear right wheel. The function of the overall

system is described in section “4.10 Control systems”.


47

4Chassis

911 GT3 (991)4 Chassis

4.1 General

The chassis of the new 911 GT3 is based on the current 911 generation, but its

components have been modified significantly compared with the 911 Carrera mod-

els and the previous model.

The 911 GT3 has the following new product features and modifications:

• Dynamic engine mounts as standard equipment

• New wheel carriers on the front and rear axle for more precise wheel guidance

• Optimization of wheel guidance on the front axle using new spring struts and ball

joints on the supporting mount and outer wishbone

• Optimization of wheel guidance on the rear axle using a new wheel carrier, opti-

mized steering geometry and ball joints on the outer wishbone and lower spring

strut connection

• Larger wheel bearings and wheel hubs on the front and rear axles for more pre-

cise wheel guidance also with higher loads through larger 20-inch wheels

• Rear axle with helper spring

• New 20-inch GT3 wheels with central lock, weight- and rigidity-optimized

• Tire Pressure Monitoring System (TPM) with racetrack mode4.1 General 47

4.2 Wheelbase and track widths 49

4.3 Front axle 50

4.4 Steering 51

4.5 Rear axle 52

4.6 Rear-axle steering 53

4.7 Brake system 56

4.8 Wheels and tires 59

4.9 Front axle lift system 62

4.10 Control systems 63

04_01_14



this SIT must be observed when working

on the chassis.


48

4Chassis

911 GT3 (991)These modifications have improved overall driving dynamics, including wheel guid-

ance, reinforced brake system and traction provided by the large 20-inch GT3

wheels.

Like the previous model, the chassis of the new 911 GT3 also has the following

characteristics and distinguishing features compared with the 911 Carrera:

• Lowering by approximately 30 mm accompanied by a corresponding lowering of

the vehicle’s center of gravity

• Specific spring, damper and anti-roll bar tuning

• Adjustable anti-roll bars at front and rear (three settings) for adaptation to individu-

ally desired handling characteristics

• Split wishbones on the front and rear axles for improved and individual camber

adjustment1

• Control arms on the front and rear axles partially with ball joints for more precise

wheel guidance

• Wheels with central lock

• Sport tires2

• Vehicle stability system Porsche Stability Management (PSM) with special tuning

and 2-stage switching function for complete deactivation (ESC OFF and ESC+TC

OFF)

• Front axle lift system (optional)

1) These modifications are only permissible for vehicle operation off public roads,

as they have a very pronounced effect on the vehicle’s handling characteristics.

When changing vehicle settings and/or modifying components, reciprocal interac-

tions must be taken into consideration.

2) There is increased danger of hydroplaning on wet roads due to the low tread

depth.


49

4Chassis

911 GT3 (991)4.2 Wheelbase and track widths

For improved driving dynamics through increased driving and steering stability, the

new 911 GT3 has a much longer wheelbase and a greater track width on both the

front and rear axles compared with the previous model.

1 - Track width increased by 54 mm at front2 - Wheel base increased by 102 mm3 - Track width increased by 31 mm at rear

These changes increase the support area of the new 911 GT3, thereby improving

longitudinal and lateral stability. The support area (wheel base x track width), which

is 7.3% larger than on the previous model, allows a further increase in vehicle stabi-

lization, resulting in high driving and steering stability, particularly in extreme driving

situations, such as driving on race circuits. The large track width on the front axle

supports steering stability during highly dynamic cornering.

Wheelbase and track widths 04_02_14


50

4Chassis

911 GT3 (991)4.3 Front axle

The McPherson front axle was largely newly developed. Unique-design wheel carri-

ers as well as larger wheel bearings and wheel hubs increase stability and load

capacity. This was necessary due to the higher load on the chassis elements as a

result of the larger wheels and enhanced driving dynamics. These measures have

increased the camber rate by approximately 10% compared with the previous

model.

The sturdy connection of the spring strut to the wheel carrier was also improved.

The twin-clamp system introduced for the previous model now has a clamping dis-

tance of 170 mm (997 GT3 II: 50 mm). This connects the spring strut even more

securely to the wheel carrier and improves rigidity for more precise wheel guidance.

The wishbone on the front axle was also completely redesigned in terms of its

stability and weight. Like the previous model, the new 911 GT3 also has a split low-

er wishbone, which allows individual camber adjustment by way of various shims for

driving on race circuits. The outer connection of this wishbone on the wheel carrier

by way of a ball joint is new. Compared to a conventional connection by means of

elastokinematic link pins, the ball joint connection reduces elasticity, resulting in

even more precise handling.

To reduce weight, the new 911 GT3 has lighter chassis springs, which offer a

weight saving of 3.5 lbs. (1.6 kg) per vehicle compared to the previous model. The

weight of the spring struts was also reduced by 3.5 lbs. (1.6 kg) per vehicle by

replacing the steel outer tube with an aluminum tube.

04_03_14


51

4Chassis

911 GT3 (991)4.4 Steering

The new 911 GT3 now features electromechanical power assistance with speed-

sensitive steering torque control. The main functions of the system were adopted

from the current 911 Carrera generation (991). The tuning of the steering functions

has been adapted specifically to suit the 911 GT3 and ensures even more immedi-

ate steering behavior with unique steering torques.

The new steering system ensures immediate and agile as well as precise steering

with informative feedback. Electromechanical power assistance also helps to

reduce fuel consumption compared with the hydraulic power assistance system

used on the previous model.

Electromechanical steering 04_04_14


52

4Chassis

911 GT3 (991)4.5 Rear axle

The multi-link rear axle was largely newly developed. Unique-design wheel carriers

and wheel hubs as well as larger wheel bearings also increase stability and load

capacity here. To further ensure the high load capacity, the subframe, including side

sections and cross member, was newly developed. In addition to geometric modifi-

cations, the weight of the cross member was also reduced by 8.6 lbs. (3.9 kg) by

using hollow-cast aluminum instead of welded steel. With this change, the subframe

has basically the same design as that used on the new 911 GT3 Cup racing car.

An additional reinforcement plate between the left and right diagonal strut is also

new. This “shear panel” increases the camber rate of the rear-axle subframe by

approximately 10% compared with the previous model and ensures even more pre-

cise wheel guidance.

The lower longitudinal and transverse control arms have also been completely

redesigned in terms of their stability and weight. Like the previous model, the new

911 GT3 also has a split lower wishbone on the rear axle for individual camber

adjustment for driving on race circuits. In addition, the lower wishbone has a ball

joint at the outer joint connections to further optimize wheel guidance. In order to

realize the rear-axle steering, the rigid tie rods were replaced with variable control

arms with electromechanically adjustable actuators.

The use of a spring/shock absorber element on the rear axle with an additional

spring (helper spring) is also new for the 911 GT3 (991). Like the 911 GT3 RS 4.0

(997 II), the new 911 GT3 also features a weight-reduced suspension system with a

lighter main spring and an additional spring.

04_05_14


53

4Chassis

911 GT3 (991)4.6 Rear-axle steering

General

The new 911 GT3 features rear-axle steering as standard. The system comprises

two electromechanical actuators, which are used instead of the conventional toe

control arms at the left and right of the rear axle. The system steers the rear axle,

depending on the speed, within a range of approximately +/- 1.5 degrees in the

opposite direction to or in the same direction as the steering angle on the front

axle. The steering angle on the rear axle thus depends above all on the steering

angle on the front axle, the driving situation and the driving speed.

At speeds of up to approximately 30 mph (50 km/h), the system steers the rear

wheels in the opposite direction (counter) to the front wheels. In terms of geometry,

this results in a virtual shortening of the wheelbase by approximately 5.9 in. (150

mm) and ensures both greater agility and day-to-day usability. This facilitates maneu-

vering and parking and keeps the turning circle small despite the large track width

on the front axle.

At speeds of over approximately 50 mph (80 km/h), the system steers the rear

wheels parallel to the front wheels (same direction). In terms of geometry, this

results in virtual lengthening of the wheelbase by approximately 18.7 in. (500 mm)

and increases driving stability, particularly at high speeds. At speeds of between 30

and 50 mph (50 and 80 km/h), the system continually switches between steering in

the same and opposite direction, depending on the driving situation.

Rear-axle steering 04_06_14


54

4Chassis

911 GT3 (991)Thanks to its variability, rear-axle steering helps to resolve the conflict of objectives

in terms of driving dynamics between agility and driving stability. The result not

only offers advantages in terms of maneuverability, driving safety and day-to-day

usability, but also increases driving dynamic performance. Rear-axle steering also

improves lap times on the Nürburgring Nordschleife and offers advantages during

other comparison tests reported in the automotive press. A significantly higher aver-

age speed can be achieved during the obstacle avoidance test (360 ft./110 m) and

slalom test (118 ft./36 m) with rear-axle steering.

Greater agility (counter steering)

• Better steering behavior and handling

• Enhanced driving dynamics and performance

• Greater driving pleasure

Increased driving stability (parallel steering)

• Enhanced driving dynamics and performance

• Further improved straight-ahead tracking at high cruising speeds

• Improved driving safety

Improved day-to-day usability (counter steering)

• Easier to maneuver and park

• Small turning circle

System description

The system comprises two electromechanical actuators, which are installed instead

of the conventional toe control arms on the rear axle and are synchronized electroni-

cally. The actuators consist of an electric motor, which drives a threaded spindle by

means of a belt drive, thereby converting the rotational movement into linear move-

ment. Rear-axle steering adjustment allows a maximum rear-axle steering angle of

approximately +/- 1.5 degrees.

By way of comparison, a steering angle of 1.5 degrees on the wheels of the front

axle is comparable with a steering angle of approximately 20 degrees from the cen-

ter position on the steering wheel.

The two rear wheels are adjusted synchronously, both in the opposite direction to

and in the same direction as the front wheels. Adjustment control essentially

depends on the vehicle speed and the steering angle on the front axle.

Electromechanical actuator 04_07_14


55

4Chassis

911 GT3 (991)

1 - Agility (up to approximately 30 mph (50 km/h)

Counter steering (maximum + 1.5 degrees)

Virtual shortening of the wheelbase (approximately 5.9 in./150 mm)

2 - Stability (from approximately 50 mph (80 km/h)

Parallel steering (maximum - 1.5 degrees)

Virtual lengthening of the wheelbase by (approximately 18.7 in./500 mm)

Driving dynamics

At speeds of up to approximately 30 mph (50 km/h), the rear wheels are turned in

the opposite direction to the front wheels. This enables the vehicle to turn faster

into the bend and allows more dynamic steering behavior. Together with the virtual

shortening of the wheelbase, this improves both agility and driving pleasure as well

as day-to-day usability (easier to maneuver and park, small turning circle). At speeds

of over approximately 50 mph (80 km/h), the rear wheels are turned in the same

direction as the front wheels. As a result, lateral forces, in particular, are built up

faster than with an unsteered rear axle. In contrast to counter steering at speeds of

up to approximately 30 mph (50 km/h), the additional cornering forces on the rear

axle are directed in the same direction as the front axle here. This results in faster

as well as more spontaneous and more harmonious initiation of changes in direc-

tion.

Function overview 04_08_14

1 - without rear-axle steering2 - with rear-axle steering


56

4Chassis

911 GT3 (991)4.7 Brake system

Technical data

Standard brake system

The new 911 GT3 has an enhanced standard brake system with brake discs made

of gray cast iron on the front and rear axle. The main features are larger brake discs

on the rear axle, modified ventilation holes on the brake discs and improved brake

ventilation with additional brake air ducts on the rear axle. These features increase

both braking performance and the stability of the brake system. The brake booster

was also redesigned. Based on the current 911 generation (991) with a tandem

brake booster made of aluminum, the new 911 GT3 has a boost ratio of 3.5:1, just

like the previous model. Compared with the boost ratio of 5.5:1 on the current 911Standard brake system 04_10_14


57

4Chassis

911 GT3 (991)Carrera models, the new 911 GT3 offers a more immediate brake pedal feel and

improved brake system control. To reduce weight and unsprung masses, the new

911 GT3 is equipped with composite brake discs derived from motor racing with

brake discs (“friction rings”) made of gray cast iron and aluminum brake disc hubs.

For improved corrosion resistance and a better look, the aluminum brake disc hubs

on the front and rear axle are painted gray. The brake disc hubs and brake discs are

connected with stainless-steel pins arranged radially.

The ventilation holes on the brake discs were enlarged from a diameter of 4 mm to

5 mm on the front and rear axle and the edges of the holes are now rounded. In

addition to better ventilation and reduced brake disc weight as a result of the larger

holes, rounding of the edges of the holes, which was adopted from motor racing,

also reduces the notch effect, thereby increasing component strength even under

very high loads. The front axle of the new 911 GT3 is fitted with a unique-design,

high-performance brake system with 6-piston aluminum monobloc fixed calipers and

brake discs with a diameter of 380 mm. The rear axle of the new 911 GT3 has a

unique-design, high-performance brake system with 4-piston aluminum monobloc

fixed calipers. The brake discs were enlarged from a diameter of 350 mm (997 GT3

II) to 380 mm.

Brake cooling

For the new 911 GT3, brake cooling on the front axle and rear axles have been

modified significantly. This results in lower brake temperatures, leading to reduced

wear and even greater braking performance under high loads. On the front axle, the

brakes are cooled in the usual way by way of brake air spoilers and air deflecting

blades. A new feature here is the significantly improved air supply system via the

brake air spoilers, particularly through a wider and larger air flow duct via the under-

body panelling.

There is a further significant improvement in brake cooling on the rear axle. With

one additional brake air duct on each side, the new 911 GT3 now has a total of four

independent, closed brake air ducts instead of two as on the previous model. Air is

still supplied to the front brake air ducts (1) via the underbody panelling and is rout-

ed in a targeted manner to the brake discs in the area of the brake calipers. The

new, additional brake air ducts (2) are offset slightly behind these and are supplied

with air freely via the underbody. Using these ducts, air is routed to just before the

brake discs so as to provide additional cooling for the brake system in the lower

area.

Brake air routing on rear axle 04_11_14


58

4Chassis

911 GT3 (991)Porsche Ceramic Composite Brake (PCCB)

The GT3 can optionally be equipped with an enhanced ceramic brake system

Porsche Ceramic Composite Brake (PCCB). The new PCCB system offers a further

improvement in braking performance and wear resistance compared with the previ-

ous model. Braking performance is increased above all by using larger brake discs

and friction surfaces and improved brake cooling. Increased wear resistance, even

under particularly high loads, is achieved above all thanks to an enhancement of the

ceramic composite material. The brake discs were enlarged from a diameter of 380

mm to 410 mm on the front axle and from 350 mm to 390 mm on the rear axle.

This measure increases the effective friction surface by approximately 14% on the

front axle and by approximately 20% on the rear axle. The cross-drilled PCCB brake

discs are mainly cooled by redesigned cooling ducts in the brake discs and the effi-

cient ventilation of the brake system.

The PCCB brake disc hubs on the front and rear axle of the new 911 GT3 are made

of forged aluminum and are anodized black. In addition to the lightweight brake

discs made of a ceramic composite material with a weight saving of approximately

50% compared with conventional brake discs made of gray cast iron, the light-

weight brake disc hubs help to reduce the vehicle weight and in particular the

unsprung masses.

The weight saving compared to stainless steel brake disc hubs is also approxi-

mately 50%. The brake disc hubs and brake discs on the front and rear axle are

connected by way of threaded sleeves and tensioning springs. The material compo-

sition of the ceramic brake discs, particularly the outer friction layer, has been com-

pletely modified. Here, a significant improvement in the wear resistance of the new

generation of discs was achieved by significantly increasing the ceramic content in

the ceramic composite material using carbon fibers.

Parking brake

Similar to the current 911 Carrera models (991), the 911 GT3 (991) features an

electrically operated parking brake. The operating button is at the left of the steer-

ing wheel on the lower part of the dashboard. The parking brake can be activated

manually using this button and deactivated while pressing the footbrake. It is also

released automatically when the driver’s intention to drive off is detected via the

accelerator pedal. The electrically operated parking brake increases comfort and

safety when the vehicle is parked and creates more space in the center console due

to omission of the handbrake lever.

PCCB brakes 04_12_14


59

4Chassis

911 GT3 (991)4.8 Wheels and tires

General

The new 911 GT3 has completely redesigned wheels on the front and rear axle.

Compared with the 19-inch wheels on the previous model, the new 20-inch GT3

wheels are not only one inch larger, but are also half an inch wider on the front axle.

The tires on the front axle are also wider.

In combination with the sports tires with larger wheel contact surfaces and the chas-

sis set up specifically for the vehicle, the new GT3 wheels offer the following advan-

tages:

• Very high lateral acceleration at high cornering speeds

• Precise handling and steering

• Optimum acceleration and braking performance

The larger wheels and tires improve both traction and performance potential. In

addition, the wider wheels and tires on the front axle offer a higher lateral force

potential with additional dynamics when steering into a bend. The wheels are made

of forged aluminum. Compared with the cast aluminum wheels on the previous mod-

el, the forged design ensures a lower weight and a high load capacity. Together with

the weight-reduced wheel design, it was therefore possible to maintain the same

wheel weight as the previous model on the front axle despite increasing the size of

the wheels by one inch to 20 inches and increasing the width by half an inch to 9

inches. On the rear axle, the wheel weight was reduced by 6.2 lbs. (2.8 kg) per

vehicle despite the increase in the wheel size by one inch to 20 inches. This

reduces not only the vehicle weight, but also the unsprung masses in order to

improve driving dynamics.

Tire sizes and tire makes can be found in

the current specifications in the PIWIS infor-

mation system.


60

4Chassis

911 GT3 (991)The wheel design is an attractive design that has evolved from the familiar 19-inch

GT3 wheel. The design with five V-shaped double spokes was significantly enhanced

and the individual spokes are now more striking. In addition, the rim flange area of

the rim base is much flatter.

With these design features, the new 20-inch GT3 wheel - apart from the geometric

increase in size by one inch - looks much bigger and its dynamic overall design

emphasizes the enhanced driving dynamics of the new 911 GT3. The platinum col-

ored paint finish on the wheels also emphasizes their high quality and adds to the

puristic appearance of the new 911 GT3. Similar to the previous model, the stan-

dard sports tires on the new 911 GT3 also offer exceptional performance potential

for high traction, lateral acceleration and short braking distances, particularly on dry

roads. There is, however, increased danger of hydroplaning on wet roads due to

reduced tread depth compared with conventional tires.

Central wheel lock

The central wheel lock is a completely new development that offers higher load lim-

its and greater suitability for driving on race circuits. The central wheel lock specific

to the new 911 GT3 is characterized by a more robust wheel hub for a significantly

increased camber rate and by driving pins that are now fixed to the wheel hub (997

GT3 II: attached to the brake disc hub). The significantly improved connection sys-

tem also includes larger bearing pins and larger wheel bearings, which are now iden-

tical to those used on the 911 GT3 Cup racing vehicles. The central bolts have a

friction-optimized trapezoidal thread and a thread run-out with a reduced notch

effect.

The new central bolts are visually distinguished by the modified toothed rim. The

dimensions and basic shape of the central bolts have been retained and the teeth

have been accentuated by distinct spaces. The central bolts on the new 911 GT3

are anodized black and have a black wheel hub cover with a silver-colored “GT3”

logo.

Central wheel lock 04_13_14


61

4Chassis

911 GT3 (991)TPM racetrack mode

Similar to the previous model, the new 911 GT3 also features Tire Pressure Monitor-

ing (TPM) for permanent monitoring of all four wheels as standard equipment. The

basic functions of the system are largely unchanged. The additional function “Race-

track mode” is new. Like the Carrera GT, the new 911 GT3 has an additional func-

tion which allows precise monitoring of an individually set tire pressure while driving

on a race circuit.

The air temperature in the tire and the tire pressure - increases during intensive dri-

ving on a race circuit. An increase in the air temperature in the tire of 122° F.

(50° C.) and therefore an increase in tire pressure of approximately 7 psi (0.5 bar)

is not unusual. When the tire pressure increases, the tire’s tread becomes deformed

and contact with the road is reduced. To achieve the best possible road contact sur-

face and therfore the best traction again, the tire pressure must be reduced. How-

ever, if the tire pressure is reduced by more than 6 psi (0.4 bar) when Racetrack

mode is switched off, the red warning message “Tire pressure” will appear on the

screen in the instrument cluster. The tire pressure warning light in the instrument

cluster stays on even after this message is acknowledged and prevents any further

system monitoring of the tire pressures that were set individually for driving on the

race circuit.

To ensure that precise tire pressure monitoring is also still possible when driving on

race circuits, Racetrack mode allows individual adaptation of the required tire pres-

sure, which is predefined in on-road mode. This function is set using the “Tire pres-

sure” menu on the instrument cluster. When Racetrack mode is activated, a stylized

race circuit with a yellow “R” is displayed permanently on the screen in the instru-

ment cluster. When you have finished driving on the race circuit, the tire pressure

must be changed back to the tire pressure required for driving on public roads in

order to guarantee safe driving on public roads. A detailed description of how to

activate and deactivate the TPM Racetrack mode can be found in the Owner’s

Manual.


62

4Chassis

911 GT3 (991)4.9 Front axle lift system

A pneumatic lift system on the front axle is optionally available for the new 911 GT3.

With new individual components, it is also possible to significantly increase the day-

to-day usability of the new 911 GT3 by lifting the body at the front by approximately

30 mm at speeds of up to 30 mph (50 km/h). This prevents damage to the body

and significantly reduces the risk of impact, e.g. when negotiating steep approach-

es and speed bumps. The lift system is also extremely useful when loading vehicles

onto race car transporters.

The function, which uses an electropneumatic function module in the PASM dampers

on the front axle, has largely been adopted from the previous model. Its operation

via a special control button in the center console is also essentially the same. The

structural design of the function module is completely new. This has been adapted

to suit the available space on the new 911 GT3 and includes new function elements.

A new valve block has also been used to refine and increase the sensitivity of the

function and position detection features of the system control.

The function module is still a compact unit located at the front of the center tunnel

and is approximately 31.5 inches (80 cm) long. The pneumatic compressor gener-

ates a pressure of up to 290 psi (20 bar) if necessary. The pressure reservoir has a

filling volume of approximately 1.06 quart (1 liter) and stores the pressure required

for operating the system. The compressed air system is controlled by means of a

valve block unit. The system weight of all components of the front axle lift system is

approximately 15.4 lbs. (7 kg).

Front axle lift system 04_14_14


63

4Chassis

911 GT3 (991)4.10 Control systems

Porsche Stability Management (PSM)

The new 911 GT3 also has a vehicle stability system with special sports tuning.

Porsche Stability Management (PSM) can also be deactivated completely in two

stages on the new 911 GT3 using the ESC OFF and ESC+TC OFF functions. With

this deactivation strategy, which is differentiated using two buttons, PSM also pro-

vides extremely sporty drivers with sufficient variation options to satisfy individual

requirements with regard to driving dynamics on the new 911 GT3. A new feature

here is the specific tuning of the new 911 GT3 with even more precise and more

sensitive control and adjustment.

The PSM basic setup offers high active safety. Traction Control (TC) for longitudinal

dynamics, with the sub-functions automatic brake differential (ABD), anti-slip regula-

tion (ASR) and engine drag torque control (MSR) as well as Anti-lock Braking System

(ABS). Electronic Stability Control (ESC) for lateral dynamics, particularly through

wheel-specific braking intervention when over- or understeering.

In the 1st switch-off stage ESC OFF, the system offers increased driving dynamics

on race circuits by deactivating lateral dynamics control (Electronic Stability Con-

trol). This enables the vehicle to be steered around corners with the required drift

using targeted steering movements and/or accelerator pedal control. The sportily

tuned longitudinal dynamics control (Traction Control) with high traction through ABD

and active safety through ASR and MSR remain active in this driving mode.

In the 2nd switch-off stage ESC+TC OFF, the driving dynamics control systems are

deactivated completely. This allows personalized racing-oriented handling on the

race circuit.


64

4Chassis

911 GT3 (991)Porsche Torque Vectoring Plus (PTV Plus)

The new 911 GT3 features Porsche Torque Vectoring Plus as standard equipment.

The system includes an electronically regulated, fully variable rear differential lock

with selective braking interventions on the rear left or rear right wheel on road sur-

faces with low grip, e.g. wet roads. Together, these systems allow high traction on

varying road surfaces, increased lateral dynamics, more precise cornering and

improved driving stability.

Unlike the previous model, which featured a rear differential lock with fixed locking

values, the electronically regulated rear differential lock used on the new 911 GT3

can be controlled actively and fully variably irrespective of the driving situation. The

fully variable rear differential lock thus offers greater traction, increased lateral

dynamics and a significant improvement in driving stability under the effects of load

changes in corners and when changing lanes, particularly at the limits of dynamic

performance. Another advantage of the fully variable rear differential lock is

improved braking behavior during full braking. When the rear differential lock is

released completely, the individual wheels are optimally controlled during ABS brak-

ing in order to achieve stable and efficient braking with the best possible decelera-

tion.

In addition, the steering behavior and the vehicle’s driving stability are improved by

selectively braking the rear right or rear left wheel on the new 911 GT3 when driving

on road surfaces with low grip, e.g. on wet roads. Selective braking is applied on

the inside rear wheel as soon as the steering is turned. This gives the outside rear

wheel higher drive torque in comparison with the inside wheel. This difference in

torque gives the vehicle a yawing moment that also supports the steering angle of

the vehicle. The result is improved steering behavior.


65

5Body

911 GT3 (991)5 Body

5.1 General

The 911 GT3 (991) is based on the lightweight and yet torsionally-rigid body of the

current 991 C4 Carrera generation in an aluminum/steel hybrid design. In addition

to the extensive use of aluminum in order to reduce the vehicle weight, the local use

of ultra-high-strength steel ensures excellent body rigidity and optimum passenger

safety. The potential for a reduced body weight is enhanced by the use of plastic as

well as 911 GT3-specific elements made of carbon fiber and glass fiber composite

materials. The low body weight of the new 911 GT3 also ensures excellent agility and

outstanding performance.

Similar to the previous model, the front end section of the bodyshell of the 911 Car-

rera 4 was used for the 911 GT3. The omission of the front-axle final drive means

that this space on the rear-wheel-drive 911 GT3 can be used for the large 16.9 gal.

(64 l) fuel tank.

The body of the new 911 GT3 is based completely on the wide body of the current

911 Carrera 4 models (991). As a result, the new 911 GT3 is 44 mm wider than the

current 911 Carrera (991) and the previous 911 GT3 model (997 II).

5.1 General 65


5.3 Body-in-white 66

5.4 Aerodynamics 67

5.5 Exterior mirrors 70


66

5Body

911 GT3 (991)5.2 Technical data

Drag coefficient cd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.33

Frontal area A [m2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2.036

Drag cd x A [m2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.672

Customer benefits

• Reduction in body weight through intelligent lightweight design (including 13%

reduction in bodyshell weight as well as 25% increase in torsional rigidity)

• Based on the 911 Carrera 4’s wide body with a larger track width on the rear axle

for enhanced driving performance and more space

• Visual differentiation from the previous model with new front and rear apron, front

spoiler lip, rear wing and SportDesign exterior mirrors

• Improved driving performance and stability through increased downforce on the

front and rear axles

• Improved braking performance through further improved cooling of the brake sys-

tem on the front and rear axles

5.3 Body-in-white

The bodyshell of the new 911 GT3 is based on the new 911 Carrera generation (991)

with a weight saving of approximately 13% compared with the previous model. This is

achieved above all by the extensive use of aluminum, particularly in the front and rear

end and in the floorpan assembly. Torsional rigidity has also been increased by

approximately 25% thanks to the intelligent lightweight construction with an aluminum-

steel composite design.

Further weight savings were made through the additional use of aluminum acces-

sories. Similar to the previous model, the new 911 GT3 also features a front hood

and doors made of aluminum. The front fenders and roof are based on the new 911

generation (991), are also made of aluminum. For further weight reduction, the brack-

ets in the roof area for securing roof transport systems have been omitted.


67

5Body

911 GT3 (991)5.4 Aerodynamics

General

The new 911 GT3 has enhanced aerodynamics with a new front and rear apron, a

new front spoiler lip, a new rear wing and a new underbody panel with an additional

rear diffuser. In addition to providing more intensive ventilation for the higher perfor-

mance radiators and brakes, the vehicle’s aerodynamics allow a further increase in

downforce on the front and rear axles in order to further increase performance poten-

tial.

Apart from the large openings for ventilating the radiators, the new front apron has

the same additional 911 GT3-specific air outlet opening of the central radiator in front

of the front hood. Downforce on the front axle is also increased through targeted air

routing. The new front spoiler lip is raised at the sides and allows a further increase in

downforce on the front axle. In addition to its distinctive blade-shaped design with the

lip contour extended well forward, the new spoiler lip now extends up at the sides in

front of the wheel housings.

At the rear of the vehicle, the downforce is achieved above all through the rear wing

with its restyled wing profile. In combination with the spoiler lip (gurney flap) integrat-

ed in the rear lid, this ensures efficient and well-balanced tuning between drag (cd val-

ue) and downforce. The new 911 GT3 also features a rear diffuser with a distinctive

aerodynamic shape in the form of an additional underbody panel in the engine area. In

combination with the rear muffler, the new engine underbody panel provides a dif-

fuser effect in order to increase downforce on the rear axle and improve the overall

downforce and performance potential.

Aerodynamic and thermodynamic tuning is also downforce-oriented and well-balanced

on the new 911 GT3. In addition to performance-oriented aerodynamics with high

downforce on the front and rear axles and well-balanced aerodynamics, efficiency

was also adequately taken into account on the new 911 GT3 with low drag and ther-

modynamic cooling of both the performance-enhanced engine and the new Porsche

Doppelkupplung (PDK).


68

5Body

911 GT3 (991)Rear lid with rear wing

The new 911 GT3 has a unique rear lid made of a carbon fiber/glass fiber composite

material (carbon/glass fiber-reinforced plastic) with integrated wing supports, a large

ram air box and a spoiler lip (gurney flap) integrated into the rear lid. Compared with

the current 911 Carrera models (991), which have an automatically extending rear

spoiler and a separate engine lid, the new 911 GT3 has a continuous rear lid with

integrated wing supports for the fixed rear wing.

The rear-lid lock, including its connection to the bodyshell, had to be moved to the

rear because of the new rear lid structure. It is connected to the side longitudinal

members by way of a unique-design component (mounting bracket) made of carbon

fiber-reinforced plastic (CFRP) in exposed carbon. Compared with the previous model

with its two individual ram air boxes, the 911 GT3 has one large ram air box extend-

ing over the entire width of the rear lid. As a result, the effective opening cross-sec-

tion was enlarged and the ram air effect was increased in order to improve the air

supply to the engine both with cooling air and intake air.

The wing supports and rear wing were also completely revamped. This allows greater

aerodynamic efficiency and increased downforce on the rear axle. The side plates of

the rear wing have inlays featuring the “3.8” logo indicating the displacement. In addi-

tion, the rear wing on the new 911 GT3 can also be adjusted individually for driving

on race circuits. Compared with the previous model with its separate spoiler lip (gur-

ney flap) at the rear edge of the rear lid, this has been formally integrated into the

rear lid on the new 911 GT3. The integrated spoiler lip not only harmonizes the rear

design, but also improves the air outflow and generates downforce on the rear axle.



this SIT must be observed when working on

the body/aerodynamic components.


69

5Body

911 GT3 (991)Engine underbody panel (rear diffuser)

The rear diffuser is completely new and is introduced for the first time with the new

911 GT3. The rear diffuser is actually an additional engine underbody panel. Together

with the rear muffler, its aerodynamic shape provides a diffuser effect, which increas-

es downforce on the rear axle.

The engine underbody panel is made of stamped aluminum and is secured directly to

the engine by way of support elements. It effectively covers the engine from below

and closes the gap between the front underbody panelling and the rear muffler. With

its upward sloping contour at the rear, its unique shape creates the aerodynamic dif-

fuser effect and further increases the downforce and performance potential of the

new 911 GT3.

05_03_14


70

5Body

911 GT3 (991)5.5 Exterior mirrors

The new 911 GT3 features SportDesign exterior mirrors as standard. These are dis-

tinguished above all by their V-shaped mirror base and a slightly modified mirror hous-

ing. These design elements make the SportDesign exterior mirrors particularly light-

weight and sporty. The new SportDesign exterior mirrors can be folded in manually.

Their mirror housing is made of lightweight plastic (polycarbonate) and is designed in

three parts. The mirror base consists of one piece and is painted completely in the

exterior color, as is the entire mirror housing. The new position on the door shoulder

ensures better airflow around the body and exterior mirrors with the added advantage

of more efficient water management and less soiling of the mirror glass.

05_04_14


6 Body – Exterior equipment

6.1 General

The unique design of the new 911 GT3 is in keeping with its intended character as a

thoroughbred standard production Sports Car and racing-oriented road vehicle. It

communicates the enormous performance potential while also fulfilling all the aerody-

namic functions which are required to realize this potential. In terms of dynamic

appearance and distinctive design, it offers excellent prospects for the continued

unique success of the new 911 GT3. The puristic, performance-oriented design, with

its sporty elegance and clearly striking design elements, is particularly characteristic

of the new 911 GT3.

6.2 Front view

The front apron on the new 911 GT3 is characterized by the striking cooling air

intakes and greater emphasis of the central air intake. These design elements give

the new 911 GT3 a powerful appearance and are effective in ensuring the required

supply of cooling air.

The shape and design of all air intakes, including the dual-branch supply air guide for

the side radiators and the striking cooling air intake in the center, create a differenti-

ated appearance within the 911 model line and emphasize the uniqueness of the new

911 GT3.

71

6Body – Exterior equipment

911 GT3 (991)

06_01_14

6.1 General 71

6.2 Front view 71

6.3 Side view 73

6.4 Rear view 74


72

The more pronounced center cooling air intake forms a slight wedge shape, which

enhances the vehicle’s aerodynamic efficiency. The spoiler lip has been made even

more striking than on the previous model and extends up at the sides in front of the

wheel housings. The side spoilers improve aerodynamics and downforce on the front

axle and make the new 911 GT3 look even wider.

The additional air outlet in front of the front hood is another characteristic design fea-

ture of the 911 GT3. This has been redesigned and integrated completely into the

front apron on the new 911 GT3 with puristic elegance and with no visible intermedi-

ate bars. Its large opening is an indication of the effectiveness of the exhaust air man-

agement system for the central radiator and also improves downforce on the front

axle. The grilles in the center and outer air intakes and in the air outlet in front of the

front hood are an unmistakable design element of the new 911 GT3. As on the previ-

ous model, their strong lattice structure protects the radiators from damage and for-

eign objects and allows high air flow rates thanks to their low obstruction level.

Another feature compared with the previous model is the new light design with stan-

dard Bi-Xenon headlights and the new front light modules of the new 911 generation

above the outer air intakes with black 911 GT3-specific inner trims (darkened). The

LED direction indicator lights and the shape of the daytime lights, likewise designed

using LED technology, are also new for the 911 GT3. The front view is rounded off by

the new SportDesign exterior mirrors with a V-shaped mirror base. Their basic shape

was adopted from the super Sports Car Carrera GT and also gives the new 911 GT3

a sporty lightness.

Front apron

The front apron was newly developed for the 911 GT3. In addition to the integration

of the new front light modules (991), the air supply for the radiators is further

improved by the larger air intakes. The spoiler lip was also newly developed and

increases the downforce on the front axle thanks to improved aerodynamics.

New characteristic features of the front apron include:

• New design with new front light modules and larger air intakes

• Modified air outlet in front of the front hood without bars

• New 3-piece spoiler lip with the spoiler contour raised at the sides

To protect the radiators from damage, the new 911 GT3, also has additional grills

both in the side openings on the front apron and in the air outlet in front of the font

hood. These have a dark-gray, powder-coated finish and ensure minimal obstruction

and high stability thanks to their fine lattice structure.


911 GT3 (991)


The even more distinctive spoiler lip with its spoiler contour raised at the sides is

new. This 3-piece spoiler lip has a black, grained finish and includes a continuous,

horizontal spoiler element and additional side elements in front of the wheel housings.

In addition to the blade-shaped lip with its spoiler edge extended well forward, the

continuation of the lip contour to the sides ensures a further increase in downforce

on the front axle.

6.3 Side view

The new GT3 is instantly recognizable as belonging to the 911 model range by virtue

of its classic 911 silhouette. A distinctive side view results above all from the fact

that the vehicle is 30 mm lower than the 911 Carrera, from the muscular look of the

rear wing and the unique wheel design.

The new one-piece 20-inch GT3 wheels with central lock are another attractive fea-

ture that has evolved from the familiar 911 GT3 wheels. The wheel design, featuring

five V-shaped double spokes, is now even more distinctive. Thanks to the unique

design elements compared with the previous model, the wheels - apart from being

larger geometrically - now look even bigger and more dynamic. The new wheels also

emphasize the high performance potential of the new 911 GT3 and their platinum

colored finish highlights its sporty elegance. The outstanding wheel design is

enhanced by the central wheel lock with its characteristic shape and anodized black

central bolt. They are a further distinguishing feature underlining the association with

motor racing. In addition to the front spoiler lip, the side sill covers and the lip-shaped

end in the rear apron are also black. This consistent design concept makes the side

view of the new 911 GT3 appear slightly elongated with clear contours.

Sill covers

The sill covers on the new 911 GT3 are the same as those used on the current 911

Carrera 4 models. They have a black grained finish and are integrated harmoniously

into the side trim panel.

73


911 GT3 (991)

06_02_14


74

6.4 Rear view

The unique rear apron on the new 911 GT3 is characterized by the centrally posi-

tioned tailpipes, the striking downward sloping end, the lateral air outlet openings and

the central air outlet opening under the rear lid. The two central tailpipes are large,

chrome-plated in black and give the rear of the new 911 GT3 a muscular appearance.

Adapted originally from the motor racing design of the 911 GT3 Cup and 911 GT3

RSR vehicles, this design feature provides a visual reference to the flow- and resis-

tance-optimized sports exhaust system.

The two lateral air outlet openings have been re-interpreted and their contours follow

the edge contour of the wing supports. They now run at an angle from bottom to top

and give both the rear view and the side view a new dynamic look. The large outlet

openings ensure thermal ventilation of the mufflers and catalytic converters located

in the quarter panels, while also improving the aerodynamics of the air flow around

the vehicle. To prevent foreign bodies from entering and in keeping with the design of

the front apron, the openings here also feature powder-coated grills.

The additional air outlet opening under the rear lid has also been re-interpreted. With

puristic elegance and no visible intermediate bars, the opening is integrated perfectly

into the lower end of the rear lid and its design is in the style of the air outlet opening

in front of the luggage compartment lid. Together with the narrow tail lights, the slim,

elongated air outlet opening emphasizes the wide, muscular look on the new 911

GT3 from the rear.


911 GT3 (991)

06_04_14


Rear apron

The rear apron has been redesigned together with the wide body and the air outlet

openings that are characteristic of the 911 GT3. Like the previous model, the new

911 GT3 also has two lateral air outlet openings and one additional air outlet opening

under the rear lid for thermal ventilation for the exhaust system and engine compart-

ment. In addition, the new 911 GT3 is fitted with dark-gray, powder-coated grills in

the openings on the rear apron.

A characteristic feature of the 911 GT3 - like its predecessor - is the central cut-out

for the exhaust tailpipes. An additional stainless-steel heat shield in this area of the

rear apron provides thermal protection. The repositioned reflectors are a distinctive

feature of the new 911 GT3 and have been adapted to the specific shape of the new

rear apron. The rear apron designed specifically for the USA market with its smaller

license plate cut-out is new compared with the previous model.

Rear wing

The fixed rear wing is a traditional element of all 911 GT3 models and along with the

front and rear apron as well as the wheels also constitutes the most striking design

feature for the new 911 GT3.

75


911 GT3 (991)

06_05_14


7 Body – Interior equipment

7.1 General

The interior of the new 911 GT3 is based on the current 911 generation (991). It is

enhanced by classic 911 GT3 features, such as Alcantara and completely newly

developed components.

New interior equipment based on the current 911 generation (991):

• Elevated center console with new operating and design concept

• New instrument panels and door panels

• Sports seats Plus (new: with electric height adjustment)

• Instrument cluster with 4.6-inch screen

• 2-zone automatic climate control

• New interior lighting (LED technology)

• Universal audio interface (AUX) in glove compartment

• New Porsche vehicle key

Differentiated features based on the classic 911 GT3 interior equipment:

• Equipment features in Alcantara (seat centers, steering wheel rim, selector lever

handle, door handles, armrests on door panels, lid of center console storage box

and rooflining. New: C-pillar trim panel and rear center tunnel trim panel)

• “GT3” logos on the door entry guards and in the tachometer (New: embroidered

into the headrests of the available seats and into the rear cover)

• Instrument cluster with yellow pointers and increment markings (New: with new dis-

plays)

• Tachometer with titanium colored instrument dial

New interior equipment including newly developed components:

• GT3 SportDesign steering wheel with shift paddles

• GT3 selector lever and speed selection gate for PDK

• PDK speed selection gate surround with “GT3” logo

• Dashboard trim and center console trim in brushed aluminum

• Rear cover with center tunnel trim panel in Alcantara

• Optional Sport Chrono clock with matt black trim ring

• Optional decorative stitching in Red (in conjunction with leather interior option)

77

7Body – Interior equipment

911 GT3 (991)

7.1 General 77

7.2 Steering wheel 80

7.3 PDK selector lever 81


78


911 GT3 (991)With the new basic components of the current 911 generation (991), the new 911

GT3 models also feature a high-quality, attractive interior. In addition, the particularly

sporty interior design has been upgraded further.

Particular highlights of the interior include the new elevated center console, the modi-

fied dashboard, the new door panels and omission of the handbrake lever. Other new

features include the 4.6-inch color display at the right of the tachometer, the 7-inch

color screen for the audio systems CDR, CDR Plus or PCM and the 2-zone air-condi-

tioning system, which allows separate temperature adjustment on the driver’s and

passenger’s side.

Interior equipment designed completely in black with elements in Alcantara is charac-

teristic of the GT3 (991). On the new 911 GT3, these include the seat centers, the

available seats, the steering wheel, the selector lever knob, the door handles, the

armrests on the door panels, the lid of the center console storage box as well as the

rear center tunnel trim panel and rooflining, including C-pillar.

In addition to various interior parts in Galvano Silver as on the current 911 generation

(991), the new 911 GT3 features the dashboard trim and center console trim in

brushed aluminum. In combination with the leather interior, the decorative trims on

the door panels are also designed in brushed aluminum. Furthermore, the new 911

GT3 optionally features red decorative stitching with the leather interior.

Interior (including leather option, decorative stitching in red 07_01_14and trims in Anthracite brushed aluminum.


Front seats

Similar to the previous model, the new 911 GT3 features Sports seats Plus with high-

er side bolsters and mechanical fore-and-aft adjustment. Backrest adjustment and for

the first time also height adjustment are controlled electrically. All seats available for

the new 911 GT3 have a “GT3” logo in Platinum Gray embroidered in the headrests.

79


911 GT3 (991)

Sports seat 07_02_14

Sports bucket seat (option) 07_04_14

Adaptive sport seat Plus (option) 07_03_14


80

Rear cover

The rear cover, instead of the rear seat system used on the 911 Carrera models, is

new. This was developed specifically for the new 911 GT3 and has a carpeted, level

cover for the seat wells as well as a center tunnel trim panel finished in Alcantara.

“GT3” logos in Platinum Gray are also embroidered at the left and right side of this

trim panel.

7.2 Steering wheel

The new GT3 SportDesign steering wheel has a rim in black Alcantara and an airbag

cover covered in black leather. Vertical adjustment and fore-and-aft adjustment, which

has been extended by 10 mm, are still controlled manually. The shift paddles for man-

ual gearshifts with the Porsche Doppelkupplung (PDK) have very short shift throws

and allow extremely precise shifting on the new 911 GT3.


911 GT3 (991)

07_05_14


7.3 PDK selector lever

The PDK selector lever in the center console has a specific GT3 design. In keeping

with the shape of a classic shift lever, the selector lever on the 911 GT3 has a round

knob in Alcantara. The shift gate was also modified for the new 911 GT3 and has two

central longitudinal stripes in black to highlight the particularly sporty setup of the

Porsche Doppelkupplung (PDK).

The trim surround on the selector lever gate was also modified and does not have a

shift pattern (P, R, N and D) on the right-hand side compared with the other 911 Car-

rera models with Porsche Doppelkupplung (PDK). On the 911 Carrera models, this is

located next to the display in the instrument cluster and on the release lever for the

selector lever knob on the new 911 GT3.

The shift-direction symbol “+” and “–” on the left-hand side of the selector lever gate

was also changed. This is red on the new 911 GT3 and the arrangement of the sym-

bols is based on motor sports. As a result, upshifts “+” take place backwards and

downshifts “–” take place forwards on the new 911 GT3. The interior design is round-

ed off by inlays in the door entry guards featuring the “GT3” logo.

81


911 GT3 (991)

07_06_14


8 Heating and air conditioning

8.1 2-zone automatic climate control

Similar to the 911 Carrera (991) Sports Car, the 911 GT3 is now also available with

2-zone automatic climate control, which comes as standard equipment on the new

911 GT3. With this system, the passenger compartment temperature can be adjust-

ed and controlled separately for the driver and passenger. The air distribution and air

flow can be set and varied using the individual setting on the vents.

In order to also provide enhanced air-conditioning comfort for the 911 GT3, the

“extended air-conditioning functions” that are available for the 911 Carrera (991) can

now also be used in the 911 GT3. The functions listed below can be selected - in the

usual way - via the on-board computer on the instrument cluster and in PCM (not in

CDR).

The extended air-conditioning functions in the 911 GT3 include:

• Automatic air-recirculation mode (use of an air quality sensor)

• Air flow adjustment (individual blower/air flow regulation)

• Extended ventilation panel

All the functions of the air-conditioning system are largely identical to those of the

911 Carrera (991) and are described in the Service Information Technik (SIT) for the

model year 2012 911 Carrera (991).

83

8Heating and air conditioning

911 GT3 (991)

8.1 2-zone automatic climate

control 83

Center console with air conditioning control panel and air outlet vents 8_01_14


85

Electrics and electronics 9

911 GT3 (991)9 Electrics and electronics

9.1 Vehicle electrical system/energy management

The vehicle electrical system used in the GT3 is based on that of the Carrera (991).

The GT3 is equipped with a 95 Ah/520 A battery.

9.2 Lighting

Similar to the previous model, the new 911 GT3 features Bi-Xenon headlights with

dynamic headlight levelling and a headlight cleaning system as standard. Their shape

and design is the same as that of the current 911 Carrera models (911). The addi-

tional lights in the front apron are new compared with the previous model. These are

also technically the same as on the new 911 Carrera models (991) and feature a nar-

row LED light strip as the daytime running lights. The turn signals and side markers

are also designed using LED technology as standard equipment. To differentiate them

from the 911 Carrera models, the inner trims on the front light modules are darkened

on the new 911 GT3.

9.1 Vehicle electrical system/

energy management 85

9.2 Lighting 85

9.3 Instrument cluster 90

9.4 Infotainment 90

9.5 Glossary 94

Front view of the 911 GT3 with LED headlights (optional) 09_02_14

BiXenon headlights 09_01_14


86


911 GT3 (991)

An innovative full-LED headlight system is available as an option for the 911 GT3. The

headlight system includes the following features:

• Headlights with dipped beam and high beam as well as additional high beam and 4-

point LED daytime running lights

• Porsche Dynamic Light System (PDLS) with dynamic headlight levelling, speed-

dependent headlight range control, dynamic cornering light and headlight cleaning

system. The central element of this system is the full-LED headlight. This essentially

consists of the following 4 components:

- Basic module

- PDLS module

- Auxiliary high beam

- Daytime running light

LED headlights (optional) and LED front light modules (darkened) 09_03_14


87


911 GT3 (991)

Similar to the differentiation between Bi-Xenon headlights, the term full-LED headlights

describes the use of LED technology not just for dipped beam but also for high

beam.

Topology

Bi-Xenon headlights

If the GT3 is fitted with Bi-Xenon headlights, headlight control units with the required

ballasts are installed on the headlights. Each ballast is integrated using a separate

LIN (Local Interconnect Network).

LED headlights

The equipment variant LED headlights uses one central AFS (automatic driving light

control) control unit, which uses a private CAN to activate two performance modules

(LEIMO) for drum control (dynamic cornering light and variable light distribution).

LED headlights 09_04_14 4-point daytime running light 09_05_14

09_06_14


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911 GT3 (991)The LED (Light Emitting Diode) light system offers the following advantages:

• Visual differentiation using an attractive headlight design and a strong differentiation

between the daytime running lights and night design

• Driving safety thanks to fatigue-free driving using daylight-like LEDs - light color with

higher perception of contrasts

• Efficiency as a result of low energy consumption and LEDs that last much longer

than Xenon lamps

• Convenient light function with no switch-on delay

The basic module (1) in the upper part of the full-LED headlight is part of the dipped

beam and ensures homogeneous and wide illumination of the road. Another part of

the dipped beam is in the Porsche Dynamic Light System (PDLS) module located

below the basic module.

With its pivot function and variable light distribution (rotating drum) this enables the

PDLS functions:

• Dynamic cornering light

• Highway light

The high beam is also contained in this module through an appropriate drum position

for the projection headlight.

The additional high beam (3) in the upper part of the full-LED headlight consists of two

sub-components and is located at the left and right of the basic module. Its high posi-

tion and additional function ensure even better illumination of the road for greater dri-

ving safety, particularly when driving at high speeds. The daytime running lights (4)

consist of four LED spotlights and a surrounding light ring.

Similar to the Bi-Xenon headlights, the full-LED headlights consist of a reflector/lens

system for the basic functions. The light for the dipped and high beam functions is

projected from the light source (LED) onto the road via a reflector and a lens or rotat-

ing drum (PDLS functions). The full-LED headlights have a very different look to the Bi-

Xenon headlights. Instead of a cone-shaped light housing with a round projection lens

and auxiliary headlight with visible reflector, the full-LED headlight consists of two

tube-shaped light housings in a stepped configuration. The dynamic design of the full-

LED headlights is supported by an attractive color scheme for the individual headlight

components.

The daytime running lights in the two headlight systems are also different. With the

standard Bi-Xenon headlights, the daytime running lights are in the auxiliary lights on

the front apron. With the optional full-LED headlights, the daytime running lights are

integrated into the headlight housing as four LED spotlights surrounded by an LED

light ring. The full-LED headlights therefore look different to the Bi-Xenon headlights

with a total of four distinguishing features: Headlight design, daytime running lights,

light color and night design.

Headlight assembly 09_07_14

LED headlights 09_08_14

Location of AFS control unit. 09_09_14


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911 GT3 (991)Tail lights

The new tail lights are also designed completely in LED technology and their shape

and function are the same as on the current 911 Carrera models. The additional

reflectors in the rear apron have a distinctive shape. The high-level 3rd brake light,

which is positioned centrally in the lower part of the rear wing, is also distinctive. The

light with its red lens originates from the super Sports Car Carrera GT and has been

integrated harmoniously and aerodynamically into the rear wing on the new 911 GT3.

09_10_14


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911 GT3 (991)9.3 Instrument cluster

The instrument cluster has been enhanced based on the current 911 generation and

the familiar 911 GT3 specific appearance. The new 911 GT3 has an instrument clus-

ter with a high-resolution color screen on the right of the tachometer. Similar to the

previous models, the instrument cluster is differentiated by its black instrument dials

with yellow needle and increment markings. The design of the tachometer instrument

dial was also adopted from the previous models. The red rpm range, which only

starts above 9,000 rpm, is a particular characteristic feature of the instrument clus-

ter.

The Sport Chrono clock on the dashboard, which is available with the optional Sport

Chrono package, adopts the design of the black instrument dials with yellow needle

and instrument markings. Another distinguishing feature of the Sport Chrono clock is

its matt black trim ring, which reduces the glare in the windshield.

The 4.6-inch, high-resolution color screen on the instrument cluster offers comprehen-

sive display options. The information Vehicle, Audio, Trip, Tire pressure including Cir-

cular path (Racetrack function), as well as the options Navigation, Map, Phone and

Chrono can also be displayed here. The new 911 GT3 features the G-forces display

as standard (available with the optional Sport Chrono package on the 911 Carrera).

The 911 GT3 (991) also features a performance display for power and torque as

standard. This shows the load point for the current driving situation in the form of a

dot display (trackball) in the power and torque map based on the engine speed and

throttle position.

9.4 Infotainment

General

State-of-the-art audio and communication systems based on the current Boxster and

911 generation are used on the new 911 GT3. The new 7-inch color screen of the

standard CDR audio system or the optional CDR Plus system and of Porsche Commu-

nication Management (PCM) is positioned higher up and is designed as a touchscreen

for fast and easy operation.

CDR audio system

The new, standard CDR audio system has an extremely high-quality user interface.

The look, feel and central functions correspond to the also new PCM generation. The

main feature of the new audio system generation is a 7-inch display with touchscreen.

All the functions (except for volume) of the CDR system can thus be controlled by

touching the color screen. This allows fast and simple navigation through the various

menus.


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911 GT3 (991)The standard audio system also features 4 speakers, a total output power of 2 x 25

W and can be used to play audio CDs and music in MP3 format (formats: mp3, aac,

wma). A 6-disc CD autochanger integrated in the CDR system is available instead of

the standard single CD drive. The standard universal audio interface makes it possible

to connect an external audio source via the AUX interface.

The system is then controlled directly on the connected device. The AUX interface is

in the glove box. There is a 12 V plug socket in the glove box for supplying power to

the external audio source. A digital satellite radio Satellite Digital Audio Radio Ser-

vices (SDARS) from the provider XM is also available in combination with the CDR

audio system in the USA and Canada.

Sound Package Plus

The new 911 GT3 offers a superior sound experience with the optional Sound Pack-

age Plus. With 9 loudspeakers divided into 7 channels as well as an external amplifier,

a total output of 235 W is available.

CDR audio system 09_11_14


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911 GT3 (991)CDR Plus audio system

The new “CDR Plus audio system” option (P25) with Sound Package Plus is based on

the same technology as Porsche Communication Management (PCM) without the navi-

gation module and includes the following features:

• Convenient light function with no switch-on delay

• 9 loudspeakers with a total output of 235 watts

• High-resolution 7-inch touchscreen

• Radio with analogue and digital double tuner for receiving radio stations in the

FM/AM bands as well as in the formats DAB, DAB+ and DMB

• Single CD/DVD drive including audio playback of music in MP3 format and

audio/video DVDs

• USB connection for various iPod and iPhone models, USB memory sticks with MP3

music and MP3 players

• Option for displaying cover art and playing podcasts and audio books. It is con-

trolled via the CDR Plus audio system

• AUX interface for connection of other external audio sources which are then con-

trolled directly via the connected device

With the CDR Plus audio system, the customer gets an attractive equipment package.

An impressive digital music experience is guaranteed, especially for customers who

have no need for the navigation function, by the USB connection and the digital dou-

ble tuner together with the improved sound output of 235 W from 9 loudspeakers.

Other useful options, e.g. the telephone module or the 6-disc DVD autochanger, can

also be combined with the CDR Plus audio system.

Porsche Communication Management (PCM) including navigationmodule

The latest generation of Porsche Communication Management (PCM) including navi-

gation module is optionally available for the 911 GT3 (991). The main features of the

latest generation of PCM in comparison with the previous version are:

• High-resolution 7-inch touchscreen

• 3D navigation map with City and Terrain models with superimposed satellite map

• Speed limit display in PCM based on navigation data

• Map display in the instrument cluster

Audio transmission via Bluetooth® is available with the new PCM generation. This

allows audio data to be transferred from external devices such as music players or

mobile phones via the Bluetooth® interface of PCM or reception of internet radio if

this function is supported by the device connected via Bluetooth®. The universal audio

interface assigned to PCM has also been modified: various iPod® and iPhone® models

can now be connected to the audio system via the USB connection.


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911 GT3 (991)Other audio options

The GT3 also includes the mobile phone preparation, telephone module, voice con-

trol, CD autochanger and CD/DVD autochanger options.

Sport Chrono package

A Sport Chrono package is also available as an option for the new 911 GT3. It

includes an analog stopwatch on the dashboard and a digital stopwatch in the instru-

ment cluster. In combination with the optional Porsche Communication Management

(PCM) system, the Sport Chrono Package features an additional performance display

in PCM, as on the previous model.


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911 GT3 (991)9.5 Glossary


2014 911 GT3 Cover 9/12/13 7:44 AM Page U3

Part Number - PNA 911 GT3 14

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