Quote Originally Posted by DennyW
That's called relative conpression actually. Relative to either the cranking rpm's, or the running rpm's.

If you crank the engine over, and it reads 125lbs, then, that is the compression ratio.

Same as if you run a 4 barrel carb. At idle, and light aceleration, it is a 2 barrel, but you have the 4 barrel option.

i think you have confused with cylinder pressure or cranking pressure with compression ratio or static ratio .
and the way he posed the question he was asking for compression ratio or static ratio , example 9 to 1 or 8.5 to 1 ratio .

if you crank the engine over ,and it reads 125lbs . then thats cylinder pressure , not the C.R.