Monday, December 13, 2010 2:18 PM
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Follow recommended RON
Q1: A reader of this column recently wrote to say he disagreed that there would better mileage and performance from using a higher RON petrol for a car whose manufacturer recommends a lower RON. TOC weighs in again on the RON95/RON97 issue.
Based on our experience and knowledge, there is ultimately no 100% conclusive answer to this question.
While one car may run better on a RON97 petrol, another car of the same specifications may not.
The ideal petrol blend is the one recommended by your car maker and certainly should not be any blend below that.
It is essential for all to understand what octane levels mean. Research Octane Number (RON) is a rating of petrol to determine its anti-knock characteristic or resistance to detonation as it burns in the combustion chambers .
The higher the RON number, the more "systematic" the combustion is, hence the higher the knocking resistance. Knocking reduces the power output. In addition, RON97 is essentially cleaner for your engine.
So using a higher RON than that for your car means using a fuel that offers less knocking, more power and better mileage.
Having said that, the true difference between the grades/ratings of petrol lies in an engine's requirements as a whole.
There are a lot of parameters to be considered such as the engine, the drivetrain, the chassis and the weight of the car before arriving at a suitable RON to use.
The best option is to follow the OEM recommendation stated in your car manual, which may also be stated at the back of the car's petrol filler cap.
Q2: I use RON95 regularly and my friend told me that adding a bit of RON97 will give better power and mileage. Is that true?
Peter
Ampang
Some vehicles require a high octane fuel, while others might run safely on lower octane rating fuel.
Adding a bit of RON97 won’t do much if you are using a normal car, therefore using RON95 will be just fine and it is also more affordable than RON97.
However if you are driving a performance car (eg with a high compression engine or force induction engine), then using RON97 is advisable for better power, mileage and protection to your engine.
Q3: Do different petrol brands affect the engine performance? I know all base oils are the same and the difference is in the additives. Currently, I am using Shell V Power. I plan to switch to Petronas Primax 97.
Monty Ashley
Kuala Lumpur
It depends, some say it does and some say it doesn’t. Basically, the difference is negligible.
The good news is that today's EFI engines using stock Engine Control Units are designed to run smoothly regardless of the petrol brand.
For vehicles using a programmable ECU (aftermarket ECU), they are tuned to specific octane ratings.
Therefore, when a different octane rating is used, the vehicle will not run smoothly and underperform.
As a result, the vehicle must be re-tuned to that particular fuel rating before all is well again.