[WardL]

If it is not knocking/pinging the gasoline is suitable for your engine. Just make sure you can hear the knock if it does knock. Between my poor hearing and a loud engine there is no way I can hear knock/ping in my engine. The engine knock will occur under load, so at idle you may be fine but going up a hill at freeway speeds the engine knocks and you can't hear it. The other thing to remember there are other factors that contribute to minimum octane requirements: Increases with age of engine, timing (you could retard your timing a little to reduce your octane requirement), cam, elevation, etc.