I was wondering what type of compression ratios an N/A H22 can safely run? Anyone have the Type S motor or pistions in their lude? That's 11:1 right? You guys able to use pump gas? (I have access to 93 octane) Has anyone installed aftermarket pistions with higher compression ratios or shaved thier head etc etc?? Just looking for some general info, no big deal. Thanks.

 

By saying what compression ratio a H22 can safely run is like who should be president. THere are a **** load of things that determine what kind of compression ur engine can run, and who the hell knows if its gonna be safe.

 

i am having 11.5:1 pistons put in my motor.....i belive the highist (safely with out tuning or retarding the timing)is 12-12.5.......other wise you will need race gas(100 octane)

 

almost anything is possible with "tuning"

 

I ran 11.5:1 with a tuned ecu. 94 octane.

 

yes i understand a lot of factors are involved "homesauce" in determining how high of a compression ratio you could run. What I was asking is what people are safely running on this board- ie people that have done it, not theorized it, or think they know what works. Of course tuning will ultimately determine how high you can go, but still you're generally gonna find a trend or an area that gets too risky to run on pump gas without terrible knock. I was just asking what type of high compression N/A setups people have had, and what type of trouble they run into. Lighten up a tad man, geez.

 

I run 12/1 comp on 91 octane.

 

I think CR is also determined by the combustion chamber's shape and mixing ability too. There are a few folks around here with 13.5-14:1 CR on pump gas.