Let me eductate you in a few things... go ahead and tell your idiot friend engine builder too. Octane rating is a rating of how cool the gas burns. The higher the number the cooler it burns. With most sportscars the compression ratio is fairly high in their cylinders... this means they require a higher octane gasoline for the combustion process so the temps don't go too high and you dont detonate the shit out of your engine. TT's have a lower compression ratio but the added boost pressure raises the compression in the cylinders so higher octane gasoline is needed in TT's as well even though they have lesser compression ratios than NA's. Now I see you have a Civic... that is not a sportscar no matter how many mods you have on it... the internals of the engine are built to low tolerences because it's an ECONOMY car... so you should use 87 octane in your Honda... because if your car has low compression ratio your not running the risk of detonating from using lower octane gasoline... and having the hotter combustion from using the lower octane gas is benefical for Honda's. Nothing funnier than seeing Honda boys fill up their Honda's with 93+ Octane because they're making their cars run slower/less powerful than they would with standard 87 octane gas LOL.
