8.1:1 CR?
 

Found some JE/SRP Pistons, .020 over,
guy want a good price for them, but in a DOHC ZC this is going to give me 8.1:1 CR. I want to keep my 9.5:1. How much of a difference will this make. I know its safe detenation wise, but I'm wanting 320whp on a .60/.63 T3.

Getting Delta Regrinds and a Custom IM.

EDIT: Just double checked and with the bore I get a bit over 8.2:1

Re: 8.1:1 CR?
 

What about maybe shaving the head a little and running a thin headgasket to bump it a little more?

Re: 8.1:1 CR?
 

yea..i'm running wisecos that will put a lil over 8.3:1 because of the deck and mill....i'm gonna be running about 25psi on a huge holset turbo... i'd say you need a bigger snail and more boost

Re: 8.1:1 CR?
 

Well by search by part numbers and finding the dome height, 7.9:1 CR is what I would yeild. Too low. Yes shaving the head is possible, but for the price of machining of the overbore and shaving the head, I could buy the right pistons.

Plus with the DOHC ZC good luck finding a thinner HG!!!
I'm gonna run 18-21 psi. Just ordered my Eagle Rods.
Big Garrets live in my backyard!! My Bro-In-Law has them all the time, if a bigger housing is required, I would have no pronb finding one.

Re: 8.1:1 CR?
 

endyn roller wave ZC pistons....done.

Re: 8.1:1 CR?
 

^^^^
$$$$$$$$

There are a few other companies that make ZC Sepcifics also for a better price.

Or A JE/SRP D16A6 pstion with a 5.7cc dome gives me 9.2:1 or so.

Re: 8.1:1 CR?
 

raceeng.com had Wiseco 9:1 ZC pistons..you can see it in the list of there own pistons. for D16a1(ZC)

Re: 8.1:1 CR?
 

Ya I know. This guy just wanted 250 Shipped. For BRand new pistons that pretty good. but 7.95:1 is too low. Gonna have to pay a bit more to get the #'s I want

Re: 8.1:1 CR?
 

8.0 is fine compression, i would run it
itll be hella easy to tune and u can run 20 psi no problems or blown hgs

Re: 8.1:1 CR?
 

Bumblezc, I will be using D16A6 SRP's in my DOHC ZC. I'm looking at like 8.3:1 and if I get the blang bling HKS HG it'll put me in the low 9's.

Re: 8.1:1 CR?
 

I'm running 9.0 Arias D16a6 pistons in my ZC which yields around a 7.8~7.9ish and I must say it sucks ass. I have to run 20~22ish psi before the car even feels alive at all. The thing was faster and funner to drive with stock pistons running 12psi.

Rollerwaves is where its at.

Re: 8.1:1 CR?
 

I was running 8.0:1 in my d16z6 and I didn't have complaints. although I would reccomend staying in the 9's

Re: 8.1:1 CR?
 

Maybe I'll invest in the expensive headgasket after all.

Re: 8.1:1 CR?
 

Invest in ARP headstuds too. Probably more important than the gasket itself ;)

Re: 8.1:1 CR?
 

I just got my ARP's today actually.

I recalculated the c/r and since I had the head milled I will be at around 8.6:1 so maybe I'll go with a stock HG after all. I am still undecided though.

Re: 8.1:1 CR?
 

What you plan on buying one of those expensive HKS gaskets? I'd mill the ---- out of your head and get some cam gears to pick up the slack. Because super low compression sucks imo.

Re: 8.1:1 CR?
 

I was debating on it but I'm not 100% sure. How well do OEM HG's hold up to boost?

Re: 8.1:1 CR?
 

With a set of studs and a few coats of copper spray the stock hg should be ok. It's not a MLS gasket, its just the standard composite style :-\

Re: 8.1:1 CR?
 

Alreday doing this and ya, I'm staying above 9-ish for CR

Re: 8.1:1 CR?
 

Even at higher boost levels (17-20 psi)?

Re: 8.1:1 CR?
 

What does the HKS Gasket Cost? Isn't it like 200-300 dollars?

Re: 8.1:1 CR?
 

It's like $115.00

http://www.overboost.com/obs/product.asp?pid=28683

Re: 8.1:1 CR?
 

I'm at around 8.1:1 in my zc with some rollerwaves and there is a HUGE difference compared to the stock pistons. The T25 was more reponsive and the power was a lot better with the stockers. I am running 16psi on a t3/4 and it feels as fast as my stock pistons ~9.3:1 at 9psi.

Re: 8.1:1 CR?
 

get head studs from ARP and ..keep the cilinder pressure down(not running too much ignition) so you don't lift the head.

Re: 8.1:1 CR?
 

Apparently, D-series don't lift heads. They shift bores.