Not Ranked
jdean, your onto something big with that piston quench area thing. You should not underestimate the quench area effect on detonation. In many cases THAT is the reason one guy can run 10.5 or 11 and 'get away with it' and another guy can't! As well as the timing curve (base and total advance) has a BIG impact on what you can and can't 'get away with'. There is more to this than a simple answer of C.R. will work well with any given motor.
Of course 'rules of thumb' are a good place to start. A little higher C.R. with alloy heads, a little lower C.R. with iron heads, for instance. Consideration must also be given to the cam profile and it's effect on the C.R. (dynamic C.R.).
My FIRST rule of thumb is: I want as much C.R. as I can get away with using PUMP GAS. Additives are a pain in the butt.
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