Hey I found a good deal on some SRP GSR 9.5 compression pistons and was wondering what the compression ratio may be about in my LS, I know it will be less... because of the larger combustion chamber but does anyone know some figures? Also would this be a good idea instead of getting the LS 8.5 compression pistons for my turbo setup? the SRP part number is 149236, would these pistons fit fine on some eagle Hbeam LS rods? Thanks for any help and tips!

 

If the pistons were developed for a GSR I would imagine they would be somewhat narrower. (someone will correct me if I'm wrong). If so you would need to do a rod mod.



There's a compression calculator that will give you an estimate.

Click here

 

i think this only applies to fitting itr and ctr pistons onto stock ls rods.

 

Ok, the SRP pistons he's refering to fits the ITR or GSR. So now I'm officially confused. Ehh I'm just a confused person I guess.

 

you'll need to modify the stock ls rods to fit oem itr or ctr pistons.

if you're using aftermarket rods and pistons, you shouldnt have this problem.

clear enough?

 

Yeah, it's clear. It was to my understanding that any piston from the "R" family (itr,ctr,gsr) would need this modification. I didn't think an aftermarket piston made for a GSR would bolt right up to an LS rod.

But hey you know more than me.

 

Ok thats cool that the rods and pistons should fit each other... i figured they would but does anyone know about what the compression ratio change is if gsr pistons are put in an LS engine? aftermarket or not... I just need to know if the SRP pistons 149236 (81.25mm 9.5:1) pistons will be even lower compression in the LS and if they would support alot of boost? they are forged... kinda low compression... if they are even lower compression ratio in the LS then I will get them... if not then I dont want to thanks

 

gsr pistons arent exactly from the 'R' family

yes i do :db:

do you happen to know the cc of the pistons?

 

Here are all the specs 81.25mm, oversized .010, Stroke 3.433, rod length 5.429, comp height 1.181, head cc 41.5 Now I know people use LS rods as kind of a poor mans stroker kit... or they swap to R series pistons for LS/Vtec setups... but im just wanting to know if I use the SRP 9.5:1 GSR rated pistons on Eagle H Beam LS rods will the compression ratio be higher or lower than the rated 9.5:1? thanks

 

The calculator here should be perfect for what you're doing, more accurate than c-speed also.

Calculator