Originally Posted by OLDMAN

The owner's manual says use at least 91 octane on the high compression engine, like in the type-s but the base RSX has a VTEC also but only requires regular or 87 octane. If you don't have a high compression engine, or a preformance chip, or are turbo'd you don't need to waste money on higher octane than what is recommended for the engine. It doesn't improve mileage or performance, you just think it does because you are paying more so therefore it must be better for my car.