I want to run forged pistons matched to LS crank and Eagle LS rods in a B18a1/ B18c1 mating. I am not planning any oil squirters and reving to about 8500 max.
I am aiming for total CR of 11.5. I am using a stock B18a1 head gasket thickness = standard=.03??
I looked at the JE and Wiseco and CP sites but none mention what forging to order when using the 41cc B18c1 chamber?? I will be boring the cylinders to 81.5. AM i lame or what??
I looked at theoldone.com but thier offerings are higher compression at 81.50.
Thanks. fobile.

 

look into CP pistons

they were used in the all motor ls/vtec champ car

 

thanks I am still looking. I think I have to find a forged piston that mimicks the P73A00 USDM B18c5 piston. I believe it is a 10.5 CR and when sqeezed by my B18c1 chamber it comes out to about 11 to 11.3 CR which is perfect.
I will have to bore the cylinders which raises another problem. Alot of the bored CR piston offerings are in the 12:1 range. I'm still searching. Thanks. fobile missile.

 

a gsr head will only increas compression by .2. you want a bigger dome than usdm itr pistons. you want a dome like jdm p30's or at least pr3's
usdm itr pistons are 10.6 cr +.2 from the gsr head + .2 from the ls crank +.1 from the .5mm over bore =11.0-11.1

 

after further review. Nothing wrong with 11 - 11.1 using the IT-R cams. I'll have more room for timing advance if my engine likes advance. I only want to use my P72 ECU and a Hondata 100. thanks for your info. fobile missile.

 

I am running a set of custom CP pistons in my LS/VTEC. 81.5mm bore. They are on eagle rods as well. I am using a B16 head though

 

If you want to go to a 4032 High Silcicone low expansion piston this Mahle set may work with minor milling to raise the CR PN#ACR181209F01
http://www.mahlemotorsports.co...0.pdf

 

CP 84mm 11.5:1 compression here. You should be able to find some off the shelf ones with lower domes to hit the compression you are looking for.