jetdriven

can I do this?? I calculate that 93 GSR B17 pistons would give me 9.7-1 compression. My car has piston slap when cold and the rings are starting to go. If Im gonna replace the rigns and pistons, well how about it?
Also, ITR pistons (11-1) are not an option as the car is an automatic and completely stock otherwise. all input appreciated.

JCushing

http://www.c-speedracing.com/howto/c.../compcalc.html

you have a b18b right?

ig try to find some p72 b18c pistons theyll give ya 10.1:1 or is your adventerous some b16a's theyy put ya at 10.8:1

btw any r pistons wont diectlt fit your rods. they have to be machinged

while your in there get some arp rod bolts there 38 bux and are well worth it

StinkyTofu

I have some almost new GSR pistons with 5520 miles on them for sale with the wristpins if you're interested.

Michael Delaney

81-81.25mm P30 b16a pistons fit right on LS rods, no machining, gives 10.99-11:1 static CR with a b18a/b head and stock 3 layer head gasket.

jetdriven

I dont think I can go anything over 10.2-1 with pump gas and an automatic. Will B17 GSR pistons or B18C5 USDM fit without having to be balanced? The piston weight is different.


[Modified by jetdriven, 8:50 PM 5/19/2002]

dubster99

You can go up to around 12:1 compression and still run 91 octane pump gas. You say you have piston slap...are you sure? If you do, you are going to need to bore the block .25mm and get .25 mm oversized pistons.

jetdriven

im to cheap to run anything higher than 87 octane pump gas
it slaps two or three times when started first time of the day. Who knows, it could be a noisy valvetrain. It just rattles for about 2 seconds first startup. It comp checks in the 180's, but it has some blowby. Im guessing the rings are weak. I just want a little more compression for more power but not so much that I fail my smog test, or cause detonation problems. It gets hot as hell in houston.

dubster99

That is probably not piston slap, since that occurs when the cylinder walls are honed too much when putting in new pistons. I would put your noise on the valvetrain.