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By Naveen Victor | Motor Trader Malaysia – Mon, Sep 16, 2013

What is RON and is there a difference between grades?

The massive 20 cent hike has made each and everyone of us just a little more concerned with how much offuel we have to burn a day, but do we actually know what we are filling our tanks with?

A number of years ago, we were enjoying RON97 at an incredible price of just RM1.80 per litre. TodayRON97 costs nearly a ringgit more and well out of reach f or the average Joe's daily budget. When we f irstgot word that a lower grade f uel would be of f ered along side RON97, many car nuts broke down in tears.

We have been using RON 95 f or a f ew years now and things aren't as bad as init ially expected. Engineperf ormance didn't take a major hit and our engines have been coping well since the switch.

Now, rumour has it that the government might bring out a lower grade of f uel slott ing in below RON95,called RON92. Though many gear-heads out there won't be too happy with the move, but as my collegueKeegan Dorai pointed out in his earlier article, there are still a considerable number of of f erings in thiscountry that are well able to accept RON92.

But the question today is about RON itself , what is it and what's the dif f erence between 92, 95 and 97.RON is an abbreviation f or Research Octane Number. The RON is determined by running the f uel in anengine with variable compression ratios and then comparing the results obtained with mixtures of iso-octane and n-heptane. In simple terms, the number af ter the RON denotes how well the engine copes withcompression without detonating prior to ignit ion.

Ford's 1.0- litre EcoBoost engine has a high compression ratioDuring the f our stroke cycle of aconventional petrol engine, one of the stages involves the compression process. During this phase the airand petrol mixture is injected into the chamber and the cylinder compresses it bef ore ignit ion. Ignit ion iscaused by a spark given out by the spark plug at the precise time f or complete combustion. Duringcompression itself , there is a tremendous build up of heat. Lower RON f uels aren't able to withstand highcompression and tend to detonate bef ore the actual spark causing 'knocking'.

High compression engines require higher octane f uel or higher RON to stop engine 'knocking'. 'Knocking'causes adverse ef f ects to engine components including severely damaging the cylinder head. Many modernengines are equipped with knock sensors, which sense the detonation of f uel bef ore the actual spark andretard the timing to compensate f or it.

Using lower RON f uels than stated by your manuf acturer can spell disaster f or your engine

So besides the knocking ef f ect, is there a considerable dif f erence between 92, 95 and 97? The answercan't be layed out in black and white. This is because higher octane f uel provides a considerable advantageto high perf ormance and highly tuned vehicles. This is due to perf ormance additives as well as highercompression. Vehicles such as the Mitsubishi Evolution 10 are high perf ormance turbocharged cars that runvery high compression ratios to perf orm at the optimum level. Theref ore, cars like the Evo 10 can only runon a minimum of RON97 to produce the rated perf ormance f igures.

Fo us commoners, when we switched f rom 97 to 95 there may have been a slight perf ormance drop, butwas only noticeable during brisk acceleration and at high speeds. During city commutes, the dif f erence canbarely be f elt. But if you do decide to jump to a lower grade f uel, check with your manuf acturer bef ore handso you don't damage your engine.

But f ret not, switching f rom RON95 to 92 is just a rumor at this point, if implemented it won't happen overnight but then again many cars today are capable of running on as low a grade as RON91, so what are weworried about?