Thread: Fuel

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Whats happenin all?

I have always thought for the longest time that if you use too high of a octane in a engine that it will kill performance. I am talking almost extremes here, like 93 octane in a engine with 6:1 compression.

I always based my argument that higher octance, although can tolerate more compression, burns slower. was I right? It makes sence because don't you have to advance the timing for higher octane fuel?

One more thing, all modern computer controlled engines with a knock sensor, will it advance timing all the way until the engine begins to knock then back off a little, or is there a preprogrammed limit?

Now i don't want to start a war over if 93 gives you more power, just the questions above.

thanks a million,
-CJP

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-cjp

thats what octane is all about the higher the number the slower it burns thats why 12-13:-1 compression motors cant run on 87 they would detonate, the fuel would ignite way to early during the compression stroke

on a computer controlled engine it will advance the timing and modify plenty of other settings to keep a stoichiometric fuel/oxygen ratio... ya know 13.7:1

I thought that was 14.7:1?

it is 14.7:1 to be stoichiometric but, the computer tries to achive that, but normally settles for 13.7 in driving conditions.

Denny, you ever feel like you have a monkey on your back?

Originally Posted by DennyW

Yep, he gives me a wack every now and then also.

What's that Monkey's Name ?

Thanks for the replies!
Awesome i was on the right track the whole time.

-CJP