Originally Posted by
Chip
Its actually very hard to generalise as to which would be better as obviously the cams are going to suit one CR better than the other, as is the rod ratio etc.
Engines are very much a package, and there isnt one answer that works on all specs.
With regards to boost threshold, not likely to be effected greatly either way as its more about the volume of air going through the turbo than what CR the engine it came from was.
With regards to power and torque, anywhere that the engine was taking lots of timing on 7.5:1 its likely to make more power on 8.5:1, and vice versa
So the high comp engine will make more power where the low comp engine has loads of ignition advance?
I always thought that the more boost an engine had, the more ignition advance it "needed" and failure to do this would result in a loss of power. Especialy when running 30psi+