b18 pistons in my b16

does anybody know what type of compression or other differences I will have if I use a set of aftermarket b18 9:1 compression pistons in my b16a? the bore size is the same so they should fit. Will the compression go up or down, I'm guessing up, but not sure?

Ok so I found out that it will drop the compression down to 8.2-8.4:1 so less initial power, but higher boost levels in the end. Do you think I should do this or just buy some 9:1 comp. pistons? Which will make the most hp, because that is really what matters here.

i personally think you should only buy stuff for your motor. especialy with internals. i'm not sure but it might be a little cheaper too due to the smaller displacement. i have a friend who has 9.5:1 pistons with somewhere between 12-15 of boost it runs great. i think anything lower than a 8.5:1 might be too low. that's just my :2cents:

Maybe I'm wrong or just dumb (or both :D), but aren't the valve reliefs on the LS pistons not the right size for the b16a head? As in a likelyhood of the valves slapping the pistons?

Maybe I'm wrong or just dumb (or both :D), but aren't the valve reliefs on the LS pistons not the right size for the b16a head? As in a likelyhood of the valves slapping the pistons?
:iagree: I'm pretty sure you're right

:iagree: I'm pretty sure you're right

I'm positive he's not.

Most companies do not make "LS specific" and "B16 specific" and "GSR specific" pistons. Check out Wiseco and Arias' part numbers for starters. They're the same for an LS, B16, ITR, etc. A 9:1 B16 piston requires less dish volume than a B18 piston, as they are typically a flat top piston. So the wiseco 9:1 B16 pistons have the same part number as the GSR 9.7-10.2:1 pistons.

The difference between LS and B16/B18C valve sizes is so minute that no company would design a piston with tolerances so tight on an LS valve that it would see PV contact on a vtec valve.

thanks for the opinions, i think i will just buy some 9:1 so I can get the most hp before I try to boost up 15lbs.

:banghead: damn my selective dyslexia. My mind didn't read the word "aftermarket" in the first post. Somehow I read it as "either use stock LS pistons or aftermarket ones" :dunno: But turboEKhatch is definently right. I'm batting 0 for the week :disappoin