How does the bigger compression pistons could make better use of an M90?
This is my understanding of it as well. When I rebuilt mine, it was recommended to me, (where I was going to be keeping my M90, and NOT running an intercooler), to increase the compression and continue to run my 3.4" pulley to prevent 'Over-driving' the blower and heating up the air TOO much.MikeGS said:I believe a slight increase in piston (mechanical) compression ratio, or a thinner head gasket allows you to run a larger pulley and keep the M-90 closer to its optimum performance range, yet still get similar cylinder pressure of someone who overdrives the M-90 (smaller pulley).
Overdriving the M-90 creates even more heat, and a charge that is less dense because of extreme heat, and more likely to cause KR.
The best scenario would be to lower the compression ratio and run and overdriven M-90 (or M-112) on top of an intercooler. That way you would get a large volume, a cooler (dense) charge, and lower the danger of detonation.