What octane to run

Indeed low test gas will detonate is high compression engines, be it due to static compression or forced induction. But in no way shape or form does high test fuel NEED high compression to be efficient.

 

10-4, just don't like to see bad information misrepresented to people

 

High octane fuel has a higher flashpoint for a more controlable combustion. It actually burns a little bit slower and it is harder to ignite. It is necessary for engines with high compression ratios and usually requires a bit more spark advance than a standard engine. In such circumstances as an engine with 11:1 or greater it would be wise to use no less than 95 octane and you will need a good high energy ignition system. Unless you have a high compression engine, higher octane fuel will do you no good whatsoever. It is also recomended for engines that will be rev'd above 7000 rpm's. The whole idea of high octane fuel is to prevent detonation (that's when the fuel spontaneously combusts in cylinder without spark). If you are determined to waste your money and wish to use high octane fuel in a car with 9.5:1 or less compression ratio you will run the risk premature carbon build up in the combustion chamber which can cause the condition that high octane fuel is intended to cure, and make short lived the span of you catalytic converter. It is harder to burn and ignite.

 

Octane is the rate at which gas burns. It doesn't need high compression to make it detonate, higher octane is used in higher compression engines because it burns slower to prevent pre-detonation.

 

Thats what i just said above

 

You also stated that higher octane needs more compression. It doesn't, 91 will run in our 3.4s. But there's no point because our engines are not high compression, and will run on 87. Higher compression engines need higher octane, but higher octane doesn't need a high compression engine.

 

you said it requires higher compression on the first page.

 

For real though, you might not want to plagarise your answers from freakin Ask Yahoo LMFAO https://answers.yahoo.com/question/index?qid=20061010181219AAM2aNa

 

Ok for real though let's get a little scientific with this. The main component in gasoline which results in higher octane ratings is trimethylpentane. This is what equates to resistance to detonation due to compression. It does not however REQUIRE higher compression to burn as you first suggested, it simply makes the fuel more resistant to pre detonation as you later mentioned.

For a factory 3.4 engine there is absolutely zero reason to run anything other than 87 octane