Ask The Editors: Is European Gasoline Like Cheating?
The short answer is no and no. Why two no’s? Because first off we say it time and time again: Octane rating is not a measurement of performance. It is a measurement of a given fuel formulation’s ability to resist preignition (also called detonation or pinging). The higher compression your engine, the more crucial higher octane rated fuel becomes because more compression means increased likelihood of early detonation. Perhaps the ultimate example of this theory in practice is the diesel engine- no spark plugs even needed, this design works on the principle that if you compress fuel and air enough, ignition happens on its own.
Secondly the reason European gas pumps (as well as parts of Asia and Australia) seem to boast higher octane ratings is because unlike the US of A, they use only the Motor Octane Number (MON). Here in the states we take two separate numbers (the Research Octane Number and the Motor Octane Number) and divide that by 2 to determine our octane ratings. You may have noticed this on the fine print of the sticker on the pump as R+M/2.
What does this mean in practice? About a differential of about 5 points to describe the fuel’s octane rating. Europe’s 96 octane fuel would be called 91 in the USA though they would in fact be exactly the same.
