9.5:1 Engine Compression

[M3SCharged]

Hello, my engine has a custom JE pistons and it is a 9.5:1 instead of 10.2:1 engine. Whatever that means. ?

Assuming the engine is new, what #'s should I see when doing a compression check?

THANKS!

[Porsche_911_GT2]

Hi, I am not too sure of this but depending on the year M3 , take a look around E46 PSI's website you will definately find out there or if not they will have a link to somewhere you can. Or email Active Autowerks call if they dont really read and reply to emails. Wish I could be of more help.

[caracas_e30]

Your compression ratio was lowered in order to accomodate the boost that the supercharger is making. A high compression motor with forced induction usually means trouble unless theres $$$$$$ involved. I see that with the modifications you listed that your car presumably has, it is a serious machine.

If you just bought the car, i highly recommend taking it to a serious shop that can diagnose the car bottoms up.

[Porsche_911_GT2]

Originally Posted by caracas_e30

Your compression ratio was lowered in order to accomodate the boost that the supercharger is making. A high compression motor with forced induction usually means trouble unless theres $$$$$$ involved. I see that with the modifications you listed that your car presumably has, it is a serious machine.

If you just bought the car, i highly recommend taking it to a serious shop that can diagnose the car bottoms up.

Not bad at all, you sure seem to know your stuff. And oh yes, if you have any videos of that car let me know, I would like to see that beast in action.