i am building an all motor nonvtec teg ls motor and i am wanting to put type r pistons in and i was wondering if anyone knew what my compratio would be i want around a 12.0:1 and i have heard that just type r pistons will do that but i need to know so i need to know if i need to shave my head or not to get to 12 thanks keith

 

With JDM type R piston which have almost a 5.5cc dome

Your compresion ratio would be 10.9 to 1.

This is assuming your deck is stock. Your head is not shaved. And the combustion chambers on your LS head are still the stock 45cc.

Also this is calcualted with .5mm over pistons. Hope this helps

CTR pistons and a two layer head gasket will get you 11.8 to 1.