Knowing what fuel to use
Posted: Sun Jan 16, 2011 1:43 pmCars that use a high compression ratio (they squeeze the petrol/air mix more to get more power out of the eventual kaboom), like most performance cars, run a higher risk of the fuel going boom early. That's called knock, detonation, or even pinging depending on how bad it is and how early it is. In any case it causes wear on the engine, loss of power, and in extreme cases can lead to engine failure (trying to blow the piston backwards).
It can be offset by slowing down the point where the spark plug fires, which results in loss of power, but in performance cars it may not be possible to retard the spark sufficiently. The result is that you can only drive at very low power or risk your engine.
If you have a car that recommends premium only then you can run it on normal 91RON fuel, but you have to be light on the throttle. It's safest to go for the better fuel. In a normal car it can make a difference to economy and power, but it depends a lot on the ECU.
Clarify that performance cars tend to run high compression ratios
It can be offset by slowing down the point where the spark plug fires, which results in loss of power, but in performance cars it may not be possible to retard the spark sufficiently. The result is that you can only drive at very low power or risk your engine.
If you have a car that recommends premium only then you can run it on normal 91RON fuel, but you have to be light on the throttle. It's safest to go for the better fuel. In a normal car it can make a difference to economy and power, but it depends a lot on the ECU.
Clarify that performance cars tend to run high compression ratios
