1SlowSi

Hey, im about to buy some pistons, but I have an LS block running a GSR head. What block do i buy the pistons for? Im gonna be running CP's and on their website you have a choice of either B18A/B or just B-Series.

Next- If I buy the 9:1's or 9.5:1's what will the compression actually be?

LS/VTEC GSR Head. Im looking for 9.5:1 but i dont see them. Im sure they can make custom ones right?

1SlowSi

bump

1 Cam Wonder

or you buy the 9:1's and mill your head .020.....

1SlowSi

yeah i could do that, but i dont like milling. So what would each compression turn out to be with my setup.

NJIN BUILDR

Give CP a call.Tell them your combo and what you want for c/r and they will give yuo the part number to order. http://www.cppistons.com/
Glenn

Unsivil_audio

Google pwns j000!

http://www.c-speedracing.com/h...c.php

Buy 9:1 pistons for an LS, the GSR head will raise compression to almost exactly 9.5:1 with an OEM 3 layer heagasket.

1SlowSi

You're the ****** man bro. didnt think c speed would have it. thanks.

actually wait. I went on there and there's a few things that i dont know.

Piston
Piston to Deck Height
and theg specs to the right of them

help me out cause i dont know about this

1SlowSi

They dont have specific for an LS an 84mm bore. It just says.. B SERIES

Unsivil_audio

I imagine its for the non-vtec b-series. Either way though you need to get 9:1's if you want 9.5:1 when you get a GSR head. Tell them you want STD bore B20 (84mm) pistons when ordering (the work on LS rods).

As for Piston to deck height, it vary's by block in your case its the LS (b18a/b), its labeled.

So here's what I did. I went through and clicked everything LS, B18a/b block, head, pr4 pistons, OEM 3 layer headgasket, and OEM b18a/b piston to deck height. That gave me a stock 9.2:1 compression. Then I went to the bore box and entered 84mm. That gave me a 9.7:1 compression ratio, so I played with the Piston Dome displacement to get it back down to 9:1 (remember the more negative the number or the more dish the piston has the less compression). I figured out that an 84mm piston with -8.30cc dish will yield 9:1 compression. Now just click the b18c1 under 'head' and you have a ~9.5:1 (9.47:1) compression ratio.

1SlowSi

why do i need to get pistons for a B20? Can i not buy them for an LS block 9:1?

turboEGhatch

Why are you so adament about having 9.5:1 compression. You won't even notice the difference between 9:1 and 9.5:1, and you'll be able to run more boost on 9:1.

TOM J

What bore size are you looking for??

1SlowSi

there is a differnece between the two. I wont notice, but my tuner will

i am looking for 84mm pistons for my LS/VTEC setup. GSR head. stock LS crank. Either 9:1's that will end up being 9.5:1 or however it can be done.

turboEGhatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1SlowSi &raquo;</TD></TR><TR><TD CLASS="quote">there is a differnece between the two. I wont notice, but my tuner will

i am looking for 84mm pistons for my LS/VTEC setup. GSR head. stock LS crank. Either 9:1's that will end up being 9.5:1 or however it can be done.</TD></TR></TABLE>

I still don't get it. Why go on a quest and potentially spend money on some 9.5:1 pistons when 9:1 pistons will work just as good as 9.5:1 if not better.

1SlowSi

here's the thing. I wont find 9.5 shelf pistons, so i will have to get 9:1's. With these and my setup, it will end up being around 9.5. I wouldnt mine 9:1's. Those were my original choice.

earl

You need to know the CP dish volume to calculate your c/r. You can IM me your set-up and I will pick the proper piston and let you know the c/r
I need:
bore size
head gasket thickness you are using
what block they are going in
what head you are using
do you know if the head or block deck have been milled, if so, how much

TOM J

Arias sells a 81mm 9.1 with a LS block and a GSR head. Arias also has a 81.5mm at 9.2 comp
83mm 9.5
84mm 9.2
84.5mm 9.3
85mm 9.5
If these are something you can use Im me and I will be able to help you out.

Tom J

1SlowSi

I need 84mm pistons. Regardless of what specs i get on the pistons, i want a C/R around 9.5:1. I dont care if its 9.2-.3. So i take it that i cant just buy pistons for the C/R that they are?? I have to calculate what it will be wtih my setup.

LS Block
84mm bore
GSR head no serious milling just resurface
stock 3 layer head gasket

Earl im going to be contacting you soon to get some sleeving done. Ill pm ya.

earl

The 9-1 CP will give you 9.3 actual c/r
If you mill .010" off your head you will get 9.5-1
I feel you would be better off sticking with the 9.3, however.