So.Cal_INTEGRA

:werd:

rgbpmp

Well when people race why do they use higher octane gas, too have extra protection against detonation?

It does kinda fool people then.

cvcsleeper

If they are running with forced induction, the compression will be higher than stock, that's why they need even higher octane. Or they just use Top Fuel.

sexy_tinky

i jus go with what my gage cluster recommends...premium.

MrFatbooty

Compression ratio has nothing to do with forced induction. It is determined by the volume of the combustion chamber and the dome displacement of the pistons. Adding forced induction to a motor does however increase the likelyhood that it will detonate.
And like I've already mentioned, "premium" means 91 octane since that's the best people in California can get a hold of.