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Old 03-13-2001, 11:02 AM   #1
fellfrosch7
Scooby Specialist
 
Member#: 2389
Join Date: Sep 2000
Location: Las Vegas, NV
Vehicle:
'98 Impreza L Wagon
'90 Talon TSi AWD

Post Compression ratio question

OK, here's a theoretical question... two same exact RS's, 2.5L engine, same turbo kit, exhaust, etc. One has the stock pistons, with stock compression, the other has aftermarket (such as Rallispec's) pistons with 8.7:1 compression ratio. What difference does the compression ratio make? From what I've read, the lower compression ratio engine will be more reliable due to less strain on the engine. How much more reliable are we talking about, rough figures? Mileages? And with better pistons, is it possible to safely raise the rev limit as well? Thanks all.

EDIT: I found one post I missed before, and if I read it correctly, a high compression/low boost engine will make more low end power and less high end power, and low compression/high boost will make top end power at a cost to the low end, correct?

[This message has been edited by fellfrosch7 (edited March 13, 2001).]
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