whats the highest compression pistons i can get and still run pump gas
11.5:1? 12:1?
just noticed i had 6 posts. would someone be able to move this into the imports area please?
depends on the TUNE.
13:1
x infinity
Depends on a ton of things. Notably, as stated, your tune. In addition, pretty much every part of your head can impact how high you go - the head material itself, the flow characteristics, your cam profile and the rest of your valvetrain can all have an impact.
A Honda S2000 runs 11.0:1 from the factory on 91 octane. Years ago Comptech was reliably running one with 6-7psi of boost using just a rising rate FPR and the stock tune.