I was wondering.....since you can run 87 oct. on 9.5 to 1 compression with iron heads can you do about 10.0 to 1 compression on aluminum heads.

I read in chevy HI-PERF that if you run aluminium heads on an engine you could get away with higher compression ratios on lower octane fuel.

Now I probably won't do this, but If I had to could I.

I would be running a longer duration camshaft with a larger overlap.

Any answers?

 

Ace,

You can use any octane fuel you want in nearly any gasoline engine so long as you adjust the timing accordingly. The down side is that on ThirdGen engines with OBD ECMs, the timing control cannot completely compensate for lower octane fuels like the OBD II systems can. If you use low octane fuel, you'll likely have to retard the timing to prevent detonation, and won't have maximum advance available for maximum power output.

If you use higher octane fuel, you can advance the base timing a bit more to to gain some power at WOT operation and under loads.

If this is for a newer, OBD II system, the PCM will correct for anything short of camel urine fuel (below 85 octane) and still advance timing to optimal at cruise.

Your longer overlap cam profile will likely result in a little less charge at lower RPMs, so detonation won't be as much of a problem until the engine gets near 2,500 or higher.

------------------
Later,
Vader
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"No matter how hard you try you can't stop us now"
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Ace - P.S. - How about hammerin' those Vi-queens?



------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

LONG LIKE THE PACKERS!!!!!!!!!!!!!!!!!!!!!
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