Octane Level

Q: Octane Level

What octane rating should I use in my Firebird? I’ve always been told to use the lowest octane fuel available – seems to work for me.

A: The thing to do is to use the lowest octane possible that does not cause detonation (pinging). There are too many factors that control this some being distributor advance, compression ration, carbon build up in the combustion chamber, carburetor adjustment, plus a bunch more. Each car is different so you have to either start at the bottom and work your way up or start at the top and work your way down.

Today’s cars have microphones attached to the blocks that listen for detonation and adjust retard accordingly via the computer. Our cars don’t so you need to use your ears.

You certainly won’t hurt it by using 92 (or higher if available).

A: You are on the right track, but it would make more sense to use the lowest octane fuel that doesn’t make your engine ping or knock. You will eventually break something if you used a lower octane fuel just because it was available.

There is no hard and fast rule saying that you must run a certain octane fuel in your 1st gen car. You must experiment and see how it runs with what’s available. If it knocks with 85 octane, then try 87. If it then runs fine, stay with that grade fuel. Using a higher octane than necessary will not benefit you car, and will even raise it’s pollution output.

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