RPM RWHP RWTQ FWHP FWTQ FW VE Green Field

2,000 95 250 112 294 1.08 54 188 9,840 Yellow2,100 104 260 122 306 1.12 59 205 10,848 VE = HP/(displacement*rpm*Comp Ratio/53888.54868)2,200 113 270 133 318 1.16 65 223 11,906 Runner CFM = RPMxFWTQ/10798 2,300 122 278 143 326 1.20 70 240 13,013 Intake CFM = CIDxRPMxVE/34642,400 130 285 153 335 1.23 75 257 14,169 based on 28" water2,500 132 278 155 326 1.20 76 261 15,374 VE Calc Data2,600 134 270 157 318 1.16 76 264 16,629 30.052,700 144 280 169 329 1.21 82 284 17,933 3022,800 155 290 182 341 1.25 88 305 19,286 9.32,900 166 300 195 353 1.29 95 327 20,6883,000 177 310 208 365 1.34 101 350 22,1393,100 186 315 219 371 1.36 106 367 23,6403,200 195 320 229 376 1.38 112 385 25,1893,300 203 323 238 379 1.39 116 400 26,7883,400 210 325 248 382 1.40 120 415 28,4363,500 220 330 259 388 1.42 126 434 30,1343,600 230 335 270 394 1.44 131 453 31,8803,700 240 340 282 400 1.47 137 473 33,6763,800 250 345 294 406 1.49 143 493 35,5213,900 262 353 308 415 1.52 150 517 37,4154,000 274 360 323 424 1.55 157 541 39,3584,100 281 360 331 424 1.55 161 555 41,3514,200 288 360 339 424 1.55 165 568 43,3924,300 295 360 347 424 1.55 169 582 45,4834,400 302 360 355 424 1.55 173 595 47,6234,500 302 353 355 415 1.52 173 596 49,8134,600 302 345 355 406 1.49 173 597 52,0514,700 307 343 361 403 1.48 175 605 54,3394,800 311 340 366 400 1.47 178 614 56,6764,900 315 338 370 397 1.46 180 622 59,0625,000 319 335 375 394 1.44 182 630 61,4975,100 318 328 374 385 1.41 182 628 63,9825,200 317 320 373 376 1.38 181 626 66,5155,300 318 315 374 371 1.36 182 628 69,0985,400 319 310 375 365 1.34 182 629 71,7305,500 322 308 379 362 1.33 184 636 74,4125,600 325 305 383 359 1.32 186 642 77,1425,700 326 300 383 353 1.29 186 643 79,9225,800 326 295 383 347 1.27 186 643 82,7515,900 326 290 383 341 1.25 186 643 85,6296,000 326 285 383 335 1.23 186 643 88,5566,100 325 280 383 329 1.21 186 642 91,5326,200 325 275 382 324 1.19 186 641 94,5586,300 324 270 381 318 1.16 185 639 97,6336,400 323 265 380 312 1.14 185 638 100,7576,500 322 260 379 306 1.12 184 635 103,9306,600 320 255 377 300 1.10 183 633 107,153

AVG 2-4.8k 211 318 249 375 1.37 121 417

Runner CFM

Intake CFM

Piston Speed

2,00

02,

100

2,20

02,

300

2,40

02,

500

2,60

02,

700

2,80

02,

900

3,00

03,

100

3,20

03,

300

3,40

03,

500

3,60

03,

700

3,80

03,

900

4,00

04,

100

4,20

04,

300

4,40

04,

500

4,60

04,

700

4,80

04,

900

5,00

05,

100

5,20

05,

300

5,40

05,

500

5,60

05,

700

5,80

05,

900

6,00

06,

100

6,20

06,

300

6,40

06,

500

6,60

0

0

50

100

150

200

250

300

350

400

450

500

550

600

650

0

2

4

6

8

10

12

FWHP FWTQ CFM

rpm

HP

,TQ

,CF

M

AVG 2k-6k 243 316 286 372 1.36 139 481AVG 2k-6k 254 310 298 365 1.34 145 501

The above FWHP & FWTQ use 15% correction factor for a T5 carFor automatics and to use 25%, type the word "auto" in this box ->

Piston Speed = VE = HP/(displacement*rpm*Comp Ratio/53888.54868) 100,000 ft/sec/sec is a safe maxRunner CFM = RPMxFWTQ/10798 Intake CFM = CIDxRPMxVE/3464based on 28" water

Piston Speed DataAtmos. Press. Stroke (Inches)(N) 3.00CID Rod Length (inches)(S) 5.09CR Rod-Stroke Ratio (n) 1.696667

= Fields to "enter" values

= Calculation (No Entries!) Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189

2,00

02,

100

2,20

02,

300

2,40

02,

500

2,60

02,

700

2,80

02,

900

3,00

03,

100

3,20

03,

300

3,40

03,

500

3,60

03,

700

3,80

03,

900

4,00

04,

100

4,20

04,

300

4,40

04,

500

4,60

04,

700

4,80

04,

900

5,00

05,

100

5,20

05,

300

5,40

05,

500

5,60

05,

700

5,80

05,

900

6,00

06,

100

6,20

06,

300

6,40

06,

500

6,60

0

0

50

100

150

200

250

300

350

400

450

500

550

600

650

0

2

4

6

8

10

12

FWHP FWTQ CFM

rpm

HP

,TQ

,CF

M

2,00

02,

100

2,20

02,

300

2,40

02,

500

2,60

02,

700

2,80

02,

900

3,00

03,

100

3,20

03,

300

3,40

03,

500

3,60

03,

700

3,80

03,

900

4,00

04,

100

4,20

04,

300

4,40

04,

500

4,60

04,

700

4,80

04,

900

5,00

05,

100

5,20

05,

300

5,40

05,

500

5,60

05,

700

5,80

05,

900

6,00

06,

100

6,20

06,

300

6,40

06,

500

6,60

0

0

50

100

150

200

250

300

350

400

450

500

550

600

650

0

2

4

6

8

10

12

FWHP FWTQ CFM

rpm

HP

,TQ

,CF

M

Fuel & HP Calcs

Green Field NOTE: All HP values are Flywheel

Yellow

HP Calculator Brake Specific Fuel Consumption (BSFC)Curb weight of car = 3327 (88 Vert 5spd)Added Weight = 20 (subs,cage,etc) Note:Weight Driver/Passenger = 210Gallons of gas = 10 (5.8-6.5#/gal) Drivetrain losses must be made up for by engine horsepower.Weight of Gas = 62

Total Car Weight = 3619

1/4 mile Elapsed Time = 13.301/4 mile MPH = 102.5

HP Formulas (5.82)cubed x (car weight)

ET based HP = (E.T.) cubed = 304Speed based HP = (.00426 x mph)cubed x weight = 301

350

12.69 Pete Jackson Gear Drive ET Calculator(Assumes some tire spin & clutch slip) Enter 1/4 MPH Traction = 100% 96% 93% 100% = No gain attainable

Stick car drivetrain losses normally 11-13% 250-350HP, 15-18% 350-500HP 103 ET = 12.35 12.86 13.38 (Possibly too much gear)Automatics vary depending on trans and converter (Between 90-125) (traction = tire spin & clutch/converter slippage) 96% = Nominal ET (About right)

93% = Power loss

Calculating EFI Injector and Fuel Requirements (More gear, traction loss,etc)

FWHP 303 X 0.500 BSFC) / (number of injectors) 8 X 0.9 (Injector Duty Cycle) = 21.0Every 10°F coolant temp below 190°F (to 170°F) the EEC increases pulse width 2% BSFC - .5 N/A, .6 turbo,.65 supercharge,.70 Nitrous (Normal Range =.8 to .9 )Change Flow Rating by Altering Fuel Pressure = Square root (new pressure 42 / 39 old pressure) X 19 Inject rating = 19.7(Stock 19# injectors can support up to 300 HP at 39# pressure and up to 330 HP at 60#) (Stock 19# injectors are rated at 39 psi)Maximum Obtainable Horsepower = 24.0 Inj. Flow X 8 # Injctr's X 0.8 / 0.56 BSFC = 274

Fuel Pump Test Summary (Lph) (5.0 Mustang Sept. 2001 "Fuel Stream Ahead) Current Boosted HP Estimator

Pump (Lph) Type 12v 13.5v (Boost-a-pump volts) HP Boost New HP New ET MPH

Weldon inline 296 353 441 250 6 352 12.7 108Walbro 255 in-tank 212 232 307 270 6 380 12.3 110Bosch 216 inline 171 207 280 302 6 425 11.9 115Airtex inline 144 182 244Walbro 155 inline 129 159 219Walbro 190 in-tank N/A 143 205Walbro 155 in-tank N/A 136 199

= Fields to "enter" values

= Calculation (No Entries!)

Fuel requirements must be based upon flywheel horsepower.

ET for a HP = cube root(5.825 cubed) x (weight)/(HP)

Enter HP (weight used from above) =

Est.ET=cube root((5.825cubed)xweight/RWHP)

Injector Size = (

17.5v --

This is a rough estimate of the potential power gain from supercharging or turbocharging and uses the weight entered above in the "HP Calculator" column.

302 0.80 Determining Runner LengthL = ((EVCD x .025 x V x 2) / (RPM x RV)) - ½D

EVCD = 720 - (advertides duration @ .006" - 30 or 20) Street Cam Runner Length = 15.1(use 30 for a race orineted cam and 20 for street cams) Race Cam Runner Length = 14.7

Other Methods of determination(Use RV = 3 and if runner length is too short use 4, Chrysler 50s mild Flat tappet = 12.9this selects which reflected wave harmonic to tune for) Chrysler Update street roller = 12.4

RV = 3 Boden/Shector Peak TQ @rpm = 14.9

Recommended TB Runner SizeD = Sqrt (CID x VE x RPM) / (V x 1130)

6,500 TB Runner Inch Diameter = 2.78

TB Runner mm Diameter = 70.6

To calculate the average diameter for a square Plenum Volumerunner, input the runner ID dimensions below: For engines operating in the 5,000-6,000 rpmRunner Height 2.00 range, plenum volume should be about 40-50%

Runner Width 1.20 of total cylinder displacement. For higher rpm

Square Runner Area = 2.40 ranges closer to 7,000-7,500 rpm, the plenum Radius of Equivalent Circle = 0.874 will need to be 10-15% larger.Equivalent Runner Diameter = 1.75 CI Volume 5,000-6,000 rpm = 136

Cubic Centimeters (cc) = 2226

Advertised Cam Duration @ .006" 272 CI Volume 7,000-7,500 rpm = 156EVCD Race Cam = 478 Cubic Centimeters (cc) = 2560

EVCD Street Cam = 468 Intake runner TaperRunner Inside Diameter (from above) 1.75 To be effective, there should be between 2%

and 5% increase in runner area over the

runner length. This is often not feasible outsidethe lower intake in some cases does not help that

much as other design variables far out-weigh it.

CID = VE (Decimal) =

L = Runner Length

EVCD = Effective Valve Closed Duration

RV = Refelctive Wave Value

V = Pressure Wave Speed (1,300 fps)

D = Runner Diameter

RPM = Max usable rpm =

VE (Vol Efficiency) =

EFI

L = ((EVCD x .025 x V x 2) / (RPM x RV)) - ½D Performer 1.02" x 1.85" 1250 - 1.20"x2.00" 14.5"

RPMI 1250 - 1.20"x2.00" 13.25"RPMII 1.16" x 2.00" 2.58sqin section 1250 - 1.20"x2.00" 13.25"Victor 5.0 1.16" x 1.96" 1262 - 1.28x2.100 11.5"

Victor 351-W 1.20" x 2.00" 2.94sqin section 1262 - 1.28x2.100 12.5"Holley SM I 1.14" x 2.11"TF Street Heat 1.20" x 2.00" 15"TF Track Heat 1.20" x 2.00" 14" gen1, 13" gen2TFS - R 1.20" x 2.00" (1.38" x 2.38" @ upper) 12.2"

TF 351-W 1.20" x 2.00" (1.38" x 2.38" @ upper) 13.3"

CarbPerformer 302 .90" x 1.90"

Performer 351-W 1.10" x 1.80"

RPM 302 1.05" x 1.86"For engines operating in the 5,000-6,000 rpm RPM 351-W 1.12" x 1.86"range, plenum volume should be about 40-50% RPM Air Gap 302 1.04" x 1.85"

of total cylinder displacement. For higher rpm RPM 351-W Air Gap 1.07" x 1.88"

ranges closer to 7,000-7,500 rpm, the plenum Victor Jr 302 1.08" x 1.90" (1.25 x 2.10 max port)Victor Jr 351-W 1.10" x 1.90" 2.70sqin section Super Victor 302 1.18" x 2.00" 3.1sqin sectionSuper Victor 351-W 1.18" x 2.00" 3.2sqin section

To be effective, there should be between 2%

runner length. This is often not feasible outsidethe lower intake in some cases does not help that

much as other design variables far out-weigh it.

idle - 5,500

1,500 - 6,5007,500

7,500

idle - 6,200 75mm1,500 - 6,700 75mm2,500 - 7,250 75mm

1,000-6,200 75mm

idle - 5,500

idle - 5,500

1.500 - 6,5001.500 - 6,5001.500 - 6,500

1.500 - 6,500

3,500 - 8,0003,500 - 7,5004,500 - 9,0004,500 - 8,500

Figuring Cross-Sectional Area Needed Figuring FPS based on RPM and CABore 4.0300 Bore 4.030Stroke 3.2500 Stroke 3.250RPM 6250 RPM 6250

CA 2.400CA required 2.400 Feet per Second 485

Figuring RPM based on CA and FPS Calculated area based on FPS and RPMBore 4.030 Bore 4.030Stroke 3.250 Stroke 3.250FPS 485 RPM 6250CA 1.710 FPS 485

RPM limit 4453 Calculated Area 2.400

Calculate FPS based on Pitot reading Calculate FPS with Flow CFM and CSAPitot tube reading in "H20 28 CFM at 28"H20 500

Cross-Sectional Area 1.71Calculate FPS 350 F.P.S. 701.7544

Valve Diameter 1.850Test Pressure " H2O 28.0

146

Lift Measured Flow0.200 58 0.342 0.397 1.162

0.300 121 0.476 0.829 1.743

0.400 159 0.469 1.089 2.324

0.500 186 0.439 1.274 2.905

0.600 190 0.373 1.302 3.485

0.700 195 0.329 1.336 4.066

0.800 195 0.287 1.336 4.647

0.900 0 0.000 0.000 0.000

1.000 0 0.000 0.000 0.000

avg 157.7 0.388 2.253 2.905

Discharge coefficient

Effective flow area

Actual flow area

0

50

100

150

200

250

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

flow

discharge coefficient

effective flow areaflo

w

0

50

100

150

200

250

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

flow

discharge coefficient

effective flow areaflo

w

0

50

100

150

200

250

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

flow

discharge coefficient

effective flow areaflo

w

V8 Compression CalculationCylinder BoreGasket BoreStrokeHead Gasket Thickness (compressed)Deck Height (Distance piston "in hole" - neg values mean piston is out-of-the-bore)Head Volume (cc) HV = Variable Volume = Piston Dish (cc) VV =Variable Volume = Piston Valve Reliefs (add all - cc) VV =Variable Volume = Piston Dome (cc) VV =Variable Volume = Valve Pocket (cc) VV =Variable Volume Total = (cc)Gasket Volume (GV in cc) = Bore (in) x Bore (in) x 12.7 x Head Gasket Thickness (in) GV =Below Deck Volume in cc = Bore (in) x Bore (in) x 12.7 x Deck Height (in) DV = Piston Displaced Volume = Bore (in) x Bore (in) x Stroke (in) x 12.7 PV =

Compression Ratio = (GV+DV+HV+VV+PV)/(GV+DV+HV+VV)

Green FieldYellow

= Fields to "enter" values= Calculation (No Entries!)

4.004.103.00

0.0470.00058.5

06006

10.033890

609.6

9.18

Green = enter value in cell Trans Gear Shift RPM ResultantRPM RWTQ RWHP Gear Ratios Final Ratios Reduction 1st-2nd RPM

2,000 250 95 1st 3.35 11.8925 4,000 2,304

2,200 256 107 2nd 1.93 6.8515 1.7357513 4,200 2,420

2,400 265 121 3rd 1.29 4.5795 1.496 4,400 2,535

2,600 274 136 4th 1 3.55 1.290 4,600 2,650

2,800 285 152 5th 0.68 2.414 1.471 4,800 2,765

3,000 289 165 5,000 2,881

3,200 292 178 Axle Ratio 5,200 2,996

3,400 300 194 3.55 5,400 3,111

3,600 302 207 The axle gear does not change the trans gear 5,600 3,226

3,800 299 216 reduction at shifts - it is a constant in all gears 5,800 3,341

4,000 296 225 Higher ratios multiply the the final ratio and 6,000 3,457

4,200 293 234 enable the faster application of torque. 6,200 3,572

4,400 286 240 6,400 3,687

4,600 280 245 6,600 3,802

4,800 271 248

5,000 261 248

5,200 251 249

5,400 238 245

5,600 224 239

5,800 210 232

6,000 200 228

6,200 190 224

6,400 180 219

6,600 170 214

4,0

00

4,2

00

4,4

00

4,6

00

4,8

00

5,0

00

5,2

00

5,4

00

5,6

00

5,8

00

6,0

00

6,2

00

6,4

00

6,6

00

100

150

200

250

300

350

1-2 Shift TQ 2-3 Shift TQ 3-4 Shift TQShift RPM

Re

su

lta

nt

To

rqu

e

4,0

00

4,2

00

4,4

00

4,6

00

4,8

00

5,0

00

5,2

00

5,4

00

5,6

00

5,8

00

6,0

00

6,2

00

6,4

00

6,6

00

100

150

200

250

300

350

1-2 Shift TQ 2-3 Shift TQ 3-4 Shift TQShift RPM

Re

su

lta

nt

To

rqu

e

Resultant Shift RPM Resultant Resultant Shift RPM Resultant Resultant HP 2nd-3rd RPM HP 3rd-4th RPM HP

110 4,000 2,674 145 4,000 3,101 171 INSTRUCTIONS:121 4,200 2,807 152 4,200 3,256 186 Use your dyno curve to populate the green132 4,400 2,941 164 4,400 3,411 195 fields in the far left column. Then enter your 138 4,600 3,075 168 4,600 3,566 204 transmission and axle data in the next column.150 4,800 3,208 178 4,800 3,721 211 The "Shift RPM" and "Resultant HP" fields158 5,000 3,342 190 5,000 3,876 220 will then populate to show what rpm you will

165 5,200 3,476 200 5,200 4,031 225

171 5,400 3,609 207 5,400 4,186 232 data and insert the HP you made at that

178 5,600 3,743 212 5,600 4,341 238

186 5,800 3,877 220 5,800 4,496 243 The graph will show the shape of your HP 200 6,000 4,010 225 6,000 4,651 246 curve after the shift and you want to start 205 6,200 4,144 230 6,200 4,806 248 experimenting with shift points that are ~10%212 6,400 4,278 235 6,400 4,961 248 higher than your peak HP point. You want 216 6,600 4,411 240 6,600 5,116 249 to maximize average HP over the usable rpm range.

If you cannot rpm 10% over the HP peak, thenmaximize the average HP.

The best shift point is a balancing act. You don't want to wind the engine too far beyond peak HP to hit maximum average HP, but you also do not want to shift too short and fall too far down the HP curve.

be at after

after shift rpm in the "Resultant HP" column.

4,0

00

4,2

00

4,4

00

4,6

00

4,8

00

5,0

00

5,2

00

5,4

00

5,6

00

5,8

00

6,0

00

6,2

00

6,4

00

6,6

00

100

150

200

250

300

350

1-2 Shift TQ 2-3 Shift TQ 3-4 Shift TQShift RPM

Re

su

lta

nt

To

rqu

e

4,0

00

4,2

00

4,4

00

4,6

00

4,8

00

5,0

00

5,2

00

5,4

00

5,6

00

5,8

00

6,0

00

6,2

00

6,4

00

6,6

00

100

150

200

250

300

350

1-2 Shift TQ 2-3 Shift TQ 3-4 Shift TQShift RPM

Re

su

lta

nt

To

rqu

e

INSTRUCTIONS:Use your dyno curve to populate the greenfields in the far left column. Then enter your transmission and axle data in the next column.The "Shift RPM" and "Resultant HP" fieldswill then populate to show what rpm you will

data and insert the HP you made at that

The graph will show the shape of your HP curve after the shift and you want to start experimenting with shift points that are ~10%higher than your peak HP point. You want to maximize average HP over the usable rpm range.If you cannot rpm 10% over the HP peak, thenmaximize the average HP.

The best shift point is a balancing act. You don't want to wind the engine too far beyond peak HP to hit maximum average HP, but you also do not want to shift too short and fall too far down the HP curve.

be at after the shift. Now, go to your dyno

after shift rpm in the "Resultant HP" column.

Ideal Header SizingArea of Primary Pipe = RPM × Motor Size ÷ 705,600 (assumes 18ga walls - .049")Pipe ID2 = RPM × Motor Size ÷ 705,600 ÷ .7854ID = (RPM × Motor Size ÷ 554,177).5Pipe ID2 = RPM × Motor Size ÷ 554,177ID = (RPM × Motor Size ÷ 554,177).5OD = (RPM × Motor Size ÷ 554,177).5 + .098” Calculate Header Primary Length -

Ideal Primary Length CID RPM Tube OD Ideal Primary Length46" 302 5,500 1.5" 43.3"

42.5" 302 6,000 1.5" 39.7"39.2" 302 6,500 1.5" 36.6"36.4" 302 7,000 1.5" 34"34" 302 7,500 1.5" 31.8"

39.5" 302 5,500 1.625" 37.3"36.2" 302 6,000 1.625" 34.2"33.4" 302 6,500 1.625" 31.6"31" 302 7,000 1.625" 29.3"29" 302 7,500 1.625" 27.3"34" 302 5,500 1.75" 28.6"

31.2" 302 6,000 1.75" 26.2"28.8" 302 6,500 1.75" 24.2"

26.75" 302 7,000 1.75" 22.5"25" 302 7,500 1.75" 21"26" 302 5,500 2.00" 39.1"

23.9" 302 6,000 2.00" 35.9"22" 302 6,500 2.00" 33.1'

20.5" 302 7,000 2.00" 30.8"19.1" 302 7,500 2.00" 28.7"50.8" 331 5,500 1.5" 30"46.6" 331 6,000 1.5" 27.5"43" 331 6,500 1.5" 25.4"

39.9" 331 7,000 1.5" 23.5"37.3" 331 7,500 1.5" 22"

Area of Primary Pipe = RPM × Motor Size ÷ 705,600 (assumes 18ga walls - .049") 302 Motor CID

6500 Max RPM

Race 1.98 O.D. Street 1.78

Race 1.88 I.D. Street 1.69

Calculate Header Primary Length -

Ideal Primary Length CID RPM Tube OD331 5,500 1.625"331 6,000 1.625"331 6,500 1.625"331 7,000 1.625"331 7,500 1.625"331 5,500 1.75"331 6,000 1.75"331 6,500 1.75"331 7,000 1.75"331 7,500 1.75"331 5,500 2.00"331 6,000 2.00"331 6,500 2.00"331 7,000 2.00"331 7,500 2.00"347 5,500 1.75347 6,000 1.75347 6,500 1.75347 7,000 1.75347 7,500 1.75347 5,500 2.00"347 6,000 2.00"347 6,500 2.00"347 7,000 2.00"347 7,500 2.00"

http://www.thedirtforum.com/headercalc.htm

Calculating Piston Speed

Z = Piston Speed in Ft/Sec/SecZ = 96,089

RPM 6,250

Stroke (Inches)(N) 3.00 A safe limit for “Z” is about 100,000 f/s squared, although . Rod Length (inches)(S) 5.09 this will cause ring flutter with 1/16” compression rings. Rod-Stroke Ratio (n) 1.696667

will have the piston closer to BDC than the long-rod motor at any point between 90° BBDC & 90° ABDC

This makes them more tolerant of extended (late intake closure) cam timing.

Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189

Long-rod motors (“n” = 1.75 to 2.1-1) will have the piston closer to TDC than the short-rod motor at any point between 90° BTDC & 90° ATDC. Short-rod motors (“n” = 1.4 to 1.75-1)

Short-rod motors have slower piston movement upwards away from BDC on the compression stroke, and will capture

Z = Piston Speed in Ft/Sec/Sec

A safe limit for “Z” is about 100,000 f/s squared, although . this will cause ring flutter with 1/16” compression rings.

than the short-rod motor at any point between 90° BTDC & 90° ATDC. Short-rod motors (“n” = 1.4 to 1.75-1)

Short-rod motors have slower piston movement upwards away from BDC on the compression stroke, and will capture more mixture at the same point of intake valve closure.

Use .006" or .050" Lift Data in the Duration Cells ICL = Intake Center LineECL = Exhaust Center Line

ICL = 115 Stock 85-88 cam ICL = 116 Stock 89-93 camECL = 115 .444/.444 lift ECL = 115 .444/.444 liftInstalled Advance 0 Installed Advance 0Intake Duration 266 Intake Duration 276Exhaust Duration 266 Exhaust Duration 266Lobe Seperation 115 Lobe Seperation 115IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)

= 18 = 22IVC (ABDC) = ((Dur - IVO) - 180) IVC (ABDC) = ((Dur - IVO) - 180)

= 68 = 74EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)

= 68 = 68EVC (ATDC) = ((Dur - EVO)) - 180) EVC (ATDC) = ((Dur - EVO)) - 180)

= 18 = 18Overlap = 36.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 40.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

ICL = 113 My 88 Cam ICL = 110 Crower 15511ECL = 112.5 ECL = 118 (4° advance ground in)Installed Advance .050" events Installed Advance .468/.486 liftIntake Duration 267 219 Intake Duration 278 218Exhaust Duration 262 212.5 Exhaust Duration 282 224Lobe Seperation 112.5 Lobe Seperation 114IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)

= 20.5 = 29IVC (ABDC) = ((Dur - IVO) - 180) IVC (ABDC) = ((Dur - IVO) - 180)

= 66.5 = 69EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)

= 63.5 = 79EVC (ATDC) = ((Dur - EVO)) - 180) EVC (ATDC) = ((Dur - EVO)) - 180)

= 18.5 = 23Overlap = 39.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 52.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

ICL = 110 270H-R14 (35-310-8) ICL = 110 270AH-R14 (35-304-8)ECL = 118 (4° advance ground in) ECL = 118 (4° advance ground in)Installed Advance .533/.544 lift Installed Advance .533/.533 liftIntake Duration 270 Intake Duration 270Exhaust Duration 276 Exhaust Duration 284Lobe Seperation 114 Lobe Seperation 114IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)

= 25 = 25IVC (ABDC) = ((Dur - IVO) - 180) IVC (ABDC) = ((Dur - IVO) - 180)

= 65 = 65EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)

= 76 = 80EVC (ATDC) = ((Dur - EVO)) - 180) EVC (ATDC) = ((Dur - EVO)) - 180)

= 20 = 24Overlap = 45.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 49.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

ICL = 110 XE264HR (35-308-8) ICL = 110 XE264HR (35-349-8)ECL = 118 (4° advance ground in) ECL = 118 (4° advance ground in)Installed Advance .533/.533 lift Installed Advance .512/.512 liftIntake Duration 266 Intake Duration 264Exhaust Duration 270 Exhaust Duration 270Lobe Seperation 114 Lobe Seperation 114IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)

= 23 = 22IVC (ABDC) = ((Dur - IVO) - 180) IVC (ABDC) = ((Dur - IVO) - 180)

= 63 = 62EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)

= 73 = 73EVC (ATDC) = ((Dur - EVO)) - 180) EVC (ATDC) = ((Dur - EVO)) - 180)

= 17 = 17Overlap = 40.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 39.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

ECL = Exhaust Center Line Yellow Green Field

Stock 89-93 cam ICL = 115 Cobra camECL = 121.5 .479/.479 (1.7 RR)Installed Advance 0Intake Duration 270Exhaust Duration 270Lobe Seperation

(ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)= 20

IVC (ABDC) = ((Dur - IVO) - 180)= 70

((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)= 76.5

EVC (ATDC) = ((Dur - EVO)) - 180)= 13.5

((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 33.5 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

Crower 15511 ICL = 108 Crower 15510(4° advance ground in) ECL = 116 (4° advance ground in)

Installed Advance 0 .531/.531 liftIntake Duration 275 212 @ .050"Exhaust Duration 275 212 @ .050"Lobe Seperation 112

(ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)= 29.5

IVC (ABDC) = ((Dur - IVO) - 180) = 65.5

((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)= 73.5

EVC (ATDC) = ((Dur - EVO)) - 180) = 21.5

((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 51.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

270AH-R14 (35-304-8) ICL = 110 XE270HR-14 (35-351-8)(4° advance ground in) ECL = 118 (4° advance ground in)

Installed Advance .512/.512 liftIntake Duration 270Exhaust Duration 276Lobe Seperation 114

(ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)= 25

IVC (ABDC) = ((Dur - IVO) - 180) = 65

((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)= 76

EVC (ATDC) = ((Dur - EVO)) - 180)= 20

((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = 45.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

XE264HR (35-349-8) ICL = 113 my 88 cam .050" events(4° advance ground in) ECL = 112

Installed Advance 4Intake Duration 219Exhaust Duration 212.5Lobe Seperation 112.5

(ICL - (Dur/2)) + (Installed Advance) IVO (BTDC) = (ICL - (Dur/2)) + (Installed Advance)= 0.5

IVC (ABDC) = ((Dur - IVO) - 180)= 38.5

((ECL + (Dur/2)) - 180) + (Installed Advance) EVO (BBDC) = ((ECL + (Dur/2)) - 180) + (Installed Advance)= 43.5

EVC (ATDC) = ((Dur - EVO)) - 180) = -11

((I Dur/2)-ICL)+((E Dur/2)-ECL) Overlap = -9.3 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

= Calculation (No Entries!) = Fields to "enter" values

Volume - Pressure Index Calculations

Description

P = piston speed in fpm, S = stroke in inches, R = engine rpm

Z = piston speed in fps/s, N = rpm, S = stroke inches, n = rod-to-stroke ratio

Calculate piston positionsSE = effecctive stroke, S = Full Stroke, R = rod length, A = crankshaft angle degrees ABDC 0-90 degrees

Nominal cylinder volumeVN = nominal cylinder volume, B = bore, S = stroke

Effective cylinder volumeVE = effective cylinder volume, B = bore, SE = effecctive stroke

Nominal compression ratioCRN = nominal compresion ratio, VN = nominal cylinder volume, VC = chamber volume

Effective compression ratioCRE = effective compression ratio, VE = effective cylinder volume, VC = chamber volume

Chamber volumeVC = chamber volume, VN = nominal cylinder volume, CRN = nominal compression ratio

Absolute cranking pressureCP = cranking pressure, CRE = effecctive compression ratio, AP = atmosheric pressure

Gauge pressureGP = guage pressure, CRE = effective compression ratio, AP = atmospheric pressure

Volume pressure indexV/P = volume pressure index, CP = cranking pressure, VE = effective cylinder volume, N = number of cylinders

Limit of engine speed based on the stress of the reciprocating components

Method of calculating max RPM based on the point of fastest piston acceleration - takes into account rod length (longer rods improve the safe RPM slightly)

Bore 4.00Stroke 3.00

Rod/stroke ratio 1.70 Total VNRod length 5.09 301.59

Atmospheric pressure 14.70 Total VE# cylinders 8 277.50

Max rpm 6250Formula

P S

P = S × R ÷ 6 3,125 3.00

P = piston speed in fpm, S = stroke in inches, R = engine rpm Z N

69,280 6250

Z = piston speed in fps/s, N = rpm, S = stroke inches, n = rod-to-stroke ratio SE S

2.76 3.00SE = effecctive stroke, S = Full Stroke, R = rod length, A = crankshaft angle degrees ABDC 0-90 degrees VN B

37.70 4.000VN = nominal cylinder volume, B = bore, S = stroke VE B

34.69 4.000VE = effective cylinder volume, B = bore, SE = effecctive stroke CRN VN

CRN = (VN + VC) ÷ VC 9.99 37.70CRN = nominal compresion ratio, VN = nominal cylinder volume, VC = chamber volume CRE VE

CRE = (VE + VC) ÷ VC 9.27 34.69CRE = effective compression ratio, VE = effective cylinder volume, VC = chamber volume VC VN

VC = VN ÷ (CRN - 1) 4.19 37.70VC = chamber volume, VN = nominal cylinder volume, CRN = nominal compression ratio CP CRE

212.85 9.27CP = cranking pressure, CRE = effecctive compression ratio, AP = atmosheric pressure GP CRE

198.15 9.27GP = guage pressure, CRE = effective compression ratio, AP = atmospheric pressure V/P CP

V/P = CP × VE × N × .3% 354.40 212.85V/P = volume pressure index, CP = cranking pressure, VE = effective cylinder volume, N = number of cylinders

Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189

SE = (S ÷ 2) + R + ((S ÷ 2) × cosA) - SQRT ((R2) - ((S ÷ 2) × sinA)2)

VN = B2 × S × .7854

VE = B2 × SE × .7854

CP = (CRE1.2 × AP)

GP = (CRE1.2 × AP) - AP

Enter data in these fields

Cylinder VN37.70

Cylinder VE34.69 effective swept volume, i.e.

R

6250

S n

3.00 1.70

R A

5.09 38.50 (piston position ABDC)S

3.00SE

2.76VC

4.19VC

4.19CRN9.99 (find this two rows above to the left)AP

14.70AP

14.70VE N

34.69 8

intake valve closing event @ A below