Ok here is where I need help. There are different part numbers for pistons that should be the same? What I am looking at is 81mm 9:1 pistons for both the b16a and the b18c1. What I don't understand is why do they have different part numbers if they have the same specifications for example the bore, compression ratio, and compression height. The only thing that I can come up with is maybe they have different sized dishes/domes to match the differently sized combustion chambers. I would really like to know why this is because the b16 pistons are a good deal cheaper.
Thanks in Advance

A link to the parts list for the lazy.
http://www.cppistons.com/PDFs/...f.pdf

 

correct me if I'm wrong, but I think if you use a 9:1 B18C piston in a B16 you will yield a different compression ratio. I believe the GSR spec piston would make your CR around 8:1 in the bB16.

 

Thanks for the input. After thinking about it they would have to be different pistons with the b16 having a shorter stroke it would need a larger dome to build the compression. I guess I should have thought about it a while longer before posting. I guess I wont be saving a little cash.

 

The pistons in question do have the same specs but they have a slightly different dish volume. There is a couple on instances where the pistons are quite close in spec, however. SC7000 and SC7015 is an example.

BTW, CP just released a piston that will give you 9-1 c/r in a b16 engine at 83mm. It can be used in the b18c to give you 9.8-1 also.