Sorry to dig up a dead thread but this is interesting.
Quote:
Originally Posted by wookie  I live in California and what I absolutely don't get is why in the hell is it damn near impossibly to get pump fuel with 91+ octane at a regular gas station. I can get 100+ but only a specialty fuel station where I get my race fuels. |
That is because California has nutty emission standards. The chemicals they put in road fuel to reduce emissions reduces the fuel's anti-knock properties. In Texas super is 93 in Cali its 91. In Colorado its even lower then that.
When you read in your manual as to the recommended octane rating make sure they are talking about the US/Canada standard octane rating. They do it a little different in Europe and Japan. There is a 8 to 10 point between European octane and US octane. 87 octane in the US or Canada is 91-92 in the UK. Europe uses the 'road octane number' (RON) while the US/Can uses the road octane number, plus the pump octane, divided by two (expressed (R+M)/2).