im putting together a ls/vtec turbo set up. i contacted arias pistons (they were not friendly at all) and they say to run a ls piston. cp pistons says to run a gsr piston................................which do i use? i know that on a ls head the intake and exhaust valves are the same size, and on the gsr the intake valve is 2mm bigger. i really dont want to have to fly cut the piston i just want to order the right piston. any knowledge would be helpful thanks.

 

up for some answers i hope

 

just use the pistons to the corresponding crank & rods...example, I have a friend that has an LS block with a GSR crank, GSR rods & GSR pistons

I have an LS block with an LS crank, LS rods & LS pistons (and have used both GSR & B16 head with no problems)

 

Real common piston to use are stock PR3 or P30 B16 pistons which with an LS crank and rods will give you somwhere in the 11's in compression (depending on bore size and head, etc.) You can use any B-series pison, even if the wrist pin is at a different height, just varries compression. Always use the same model of rods to crank, pistons, just depends on what compression you want really.

 

im not goin to be running a fatory piston, i have eagle (ls) rods and on a turbo factory pistons are not going to make it far lol

 

as far as i know... the model piston that matches your head will yield the compression designated by the manufacturer... other will be higher or lower depending on the combustion chamber changes...


as an example...
ls/vtec w/gsr head
9:1 gsr piston will yield 9:1
and im pretty sure 9:1 ls piston with the same setup will yeild around 9.5-9.8:1
(cant really remember exactly off hand but i know matching head and piston will give you compression ratio listed by manufacturer)

hope that helps..

 

if youre building a turbo motor you are most likely using dish pistons wouldnt you...are you worried about hittin the valves? sorry if i am being ignorant

 

there is still valve reliefs in a dished piston, vtec pistons have a bigger intake relief than ls's do, and in a theory yes i guess im worried bout the intake valve (vtec) hitting if i had a ls piston in it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by saleensolution &raquo;</TD></TR><TR><TD CLASS="quote">im not goin to be running a fatory piston, i have eagle (ls) rods and on a turbo factory pistons are not going to make it far lol</TD></TR></TABLE>

I know. Point being that it doesn't matter. Mix and match as you choose. Turbo companies don't make "LS/VTEC" pistons, only because there's no 1 way to do LS/VTEC, so there will be any number of different compression ratios. Just look at dome volume and figure out aproximatly what compression you want. With a GS-R head, a flat-topped piston in a standard bore will be around 9.5:1. Anything more or less, well, you can figure that out.

Forged pistons don't come in a "LS" or "GS-R" model. It's bore size and dome volume. That's it. So there is no answer to your question. Figure what Compression you want and order your pistons based upon that.

 

yeah, your making it more complicated than it should be...
I rev mine to 9500 without any issues with a stock head & aftermarket valvesprings & retainers.

 

Shouldn't this be in tech or forced induction?? What does this have to do with drag racing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Quik Chris &raquo;</TD></TR><TR><TD CLASS="quote">Shouldn't this be in tech or forced induction?? What does this have to do with drag racing?</TD></TR></TABLE>

your right i dont know why i asked