Originally Posted by StreetRacingCRX
I always put the highest octane I can it cleans your fuel system like your injector and your valves. Hihg octance gas will not mess up your engine unless you put like octane 100+ all the time
It doesn't do anything unless the engine requires it. The engine doesn't take advantage of the extra octane, so you are essentially throwing money down the toilet if you put 91 octane in a car that can run perfectly fine on 87 octane.