PISTONS ??

[rickylsi]

How can i find out the compression of my pistons that I am going to install in my car???? I was told they were high compression but is there anyway to tell exactly????? Thanks Ricky

[TheChosenOne]

First, the compression of a piston is not necessarily the the pistons actual compression, but rather the compression ratio that will be yeilded by the cylinder itself when the piston is in your motor. The same piston will yeild different compression ratios depending on the head/block combo.
First, you need to figure out what kind of piston you have: PR3, PR4, P72...ect. As far as oem pistons go, Ls yeild the lowest compression ratio, followed by GSR pistons, then ITR pistons, then b16 pistons, and the higest are ctr pistons.

Here is a rough estimate of the compression ratios that your specific setup will yeild with the different oem pistons.

(information from b20vtec.com)

B16A block, B16 head and:
GS-R pistons 8.7
USDM ITR pistons 9.5
92-93 GS-R pistons 9.56
JDM ITR pistons 9.9
B16A pistons 10.2
CTR pistons 10.8

B16A block, GS-R head and:
GS-R pistons 9.0
USDM ITR pistons 9.9
92-93 GS-R pistons 9.94
JDM ITR pistons 10.3
B16A pistons 10.6
CTR pistons 11.3

B18C block, B16/ITR head and:
GS-R pistons 9.65
USDM ITR pistons 10.6
92-93 GS-R pistons 10.64
JDM ITR pistons 11.0
B16A pistons 11.36
CTR pistons 12.0

B18C block, GS-R head and:
GS-R pistons 10.0
USDM ITR pistons 11.0
92-93 GS-R pistons 11.1
JDM ITR pistons 11.5
B16A pistons 11.9
CTR pistons 12.6

B18B (LS) block, B16/ITR head and:
GS-R pistons 9.8
USDM ITR pistons 10.8
92-93 GS-R pistons 10.84
JDM ITR pistons 11.2
B16A pistons 11.6
CTR pistons 12.3

B18B (LS) block, GS-R head and:
GS-R pistons 10.2
USDM ITR pistons 11.2
92-93 GS-R pistons 11.3
JDM ITR pistons 11.7
B16A pistons 12.1
CTR pistons 12.85

[TheChosenOne]

P.S.

Keep in mind that the common misconception that the higher the compression, the more the horsepower. While this might be true, 93 octane pump gas has a threshold at about 12.5:1. And really, any motor in the 12's has some serious tuning done to it.
As far as street applications go, keep it between 9:1 and 11.5:1. Anywhere above that will cause your engine to detonate and/or lean out which will be bye-bye to your setup.

...................rep's please;)

[rickylsi]

I guess i should have said what i had to make it a little easier. SORRY. I have a d16z6 block with JE SRP cutom made pistons(as i was told). The only thing the pistons have on them is SRP and the number 10. I am buying a ZC head that has been built with cam valve etc and port and polish plus he has the ecu chromed for a high comp motor. I wanna make sure i do this right though.

[TheChosenOne]

Damn you just knocked my black ass back down to earth. This is what I get for getting cocky. Lol.

Na, but foreal. Either contact the dude who you got the pistons from, or call the company. Are you going boost, spray, or N/A?

[rickylsi]

Goin NA. Tryed callin JE(THEY SUCK) The guy said whats the part number and without that he couldnt help. The guy I got the pistons block and rods from said his head was shaved and he was running 13;1 which mine is not shaved. The one im gettin the head from hadthe ecu programed for 12;1. By the way I really appreciate the advice.

[TheChosenOne]

Goin NA. Tryed callin JE(THEY SUCK) The guy said whats the part number and without that he couldnt help. The guy I got the pistons block and rods from said his head was shaved and he was running 13;1 which mine is not shaved. The one im gettin the head from hadthe ecu programed for 12;1. By the way I really appreciate the advice.
No problem man. I know, when your building a motor, you always want to try and do everything perfect to limit the number of things that could go wrong. Well, with the little information the guy gave you, your probably going to be in the high 12's. Did he have the d16 block with the zc head, too? Honestly, the safest, and only way your gunna be able to tell is to find out the exact number of cc's in yor combustion chamber and work the math yourself. There is a web site that has the equation, but honestly... its tough shit.

[rickylsi]

Cool thanks again.

[koukis14]

P.S.

Keep in mind that the common misconception that the higher the compression, the more the horsepower. While this might be true, 93 octane pump gas has a threshold at about 12.5:1. And really, any motor in the 12's has some serious tuning done to it.
As far as street applications go, keep it between 9:1 and 11.5:1. Anywhere above that will cause your engine to detonate and/or lean out which will be bye-bye to your setup.

...................rep's please;)

isn't the compression ratio in an S2000 12.5:1?

[TheChosenOne]

isn't the compression ratio in an S2000 12.5:1?
hahaha... honestly, I couldn't tell you. But consider this....:thinking:....If it does come off the assembly line at 12.5, then I assure you that HONDA tuned the SHIT out of that motor. But I would like to see somemore info on this racing spec S2000 you speak of.