(10-17-2025, 01:06 PM)Gone in 60 Wrote: Is octane measurement the same in the U.S. as it is in other countries? Just wondering if 99 octane in England is 99 octane here.
No. It is all about knocking, but the way to calculate the Octane No is different between Europe and the USA. It's a bit like Celsius and Fahrenheit.
In Europe the Octane is given in RON (Research Octane Number), in USA and Canada it is AKI (Anti-Knock Index).
There are formulas, to convert the numbers.
Europa (RON)
USA (AKI ≈ (R+M)/2)
| 95 RON | ≈ 91 AKI | Normal / Super |
| 98 RON | ≈ 93–94 AKI | Super Plus / Premium |
| 91 RON | ≈ 87 AKI | Regular |
(info is from chatgpt.com)