European fuel really isn't all that much higher, if at all. We simply use a different measure. Just like the Imperial vs Metric differences. A meter is still a meter, even if we insist on measuring it in feet.
Ditto for gasoline, here in the US we use the (RON+MON)/2 measure. Or in other words, the average of the Research Octane Number and the Motor Octane Number. This is known as the Anti-Knock Index.
Most of the rest of the world displays the RON figure. AKI is about 5-6 points lower than RON for most fuels. So something that is listed as 99 RON in Europe would be the same as 93 AKI you see on our pumps here.
Originally Posted By: artificialist
Originally Posted By: Quattro Pete
Originally Posted By: d00df00d
The US doesn't recognize European safety standards,
And then there are also different emissions standards that require development and testing of different ECU programming.
Yes, and sometimes even reprogramming the ECU isn't enough.
Sometimes an air pump, an EGR valve, pre-cat, or some other device is added to an existing engine to meet California smog.
Cams are sometimes different as well.
The other limiting factor is that all gasoline cars have to be compatible with 91 (or lower) octane gasoline and 10% ethanol. In Europe the fuel may have a higher octane level and lower ethanol content. Diesel fuel may also be different between the USA and Europe.