Originally Posted by KnightmareVette

What I want to know is other than making the engine knock like a very determined Jehovah's Witness on a saturday morning,

Originally Posted by kwik_ta

It is perfectly fine to run 87 octane in your vette as long as you do not have a heavy right foot. If you drive it sanely... there will be no problems. Under the conditions that I drive... or others on this board... 87 octane would detinate and grenade the motor.

Originally Posted by rick lambert

Of course mines an 87, and I have been using 87 for 6 years without any pinging.

Originally Posted by redwing76

Whats your secret? The group thinks not. Its one of those mysteries
where I believe what I want to believe.
I tryed 87 it made little or no difference. Picture this a tanker truck pulls into the station and out of the tank comes 3 grades of gasoline?

Originally Posted by 85 500 horse

The octane rating that you run in your car was determined by the factory that produced your car. Running a higher octane than what is required will do nothing more for you car, but it will burn a deeper hole in your wallet. If the manual says to put in 87 octane, then that's what you should put in. Some people believe they are treating their car when they fill up with a higher octane than what is called for. The only people they are treating are the gas companies by freely and mistakingly giving them a present in the form of money.

The only time you should put a higher octane in your car than what the book calls for is when your engine has been modified, the compression has been raised or when the car needs the extra octane due to modifications. My car calls for 91 octane, but because I have heavily modified my car's engine and the compression is now 11:1, I need to put in a minimum of 93 octane. Anything less will cause excessive pinging. Even race fuel wouldn't hurt. This fuel run through a stock car could damage the engine. If you run excessively high octane in a vehicle (like race fuel) that hasn't been built for it, you can cause irreversible damage.

For novices reading this post, when you go into an auto parts store and see the cans of 100 or 110 octane racing fuel, DO NOT put them into your tank unless it is called for. You run the risk of burning your valves or causing other damage. For your car to run at peak effieiency, put in what is called for. In Corvettes, that is usually 91 octane. 93 or 94 octane won't do any harm, just don't go to 100 or higher.

Originally Posted by Nathan Plemons

The ultimate stupidity of most people comes from buying fuel of a higher octane rating than what they need. The fact of the matter is that you want to run the LOWEST octane fuel you can without picking up any timing retard. If you can run full spark advance with no detonation on 87 octane then you are simply throwing money away by buying 89, 93, or 100 octane fuel. You're costing yourself horsepower AND money.

The idea that high octane fuel is "better" is complete crap. If you truly understand what gasoline ratings mean then you'll know what I'm saying is true. If you're like the majority of the public you'll argue till you're blue in the face with no facts to back it up.

To accurately determine what fuel your car needs, get the engine as hot as it's ever gonna be and run it in the hottest climate it is ever going to see. Then use some sort of logging software to determine if there is any knock detected and thus any corresponding timing retard at wide open throttle. If you see timing retard then you need to go up a grade in fuel. As soon as you find the octane rating that allows for zero timing retard under the most extreme conditions, STOP you've found your fuel. It's a tedious task that most people don't bother with.