im building my 98 gsr, and im using blox b's with supertech valvetrain, boring .20 over, using stock GSR rods. I have a jdm itr 98+spec 4-1 header and a thermal R&D exhaust. Planning on also using a blox IM. What pistons do you guys think i should use. I herd the p30 would boost up my compression but then agian they arent great to use in a gsr motor. Can anyone help me out?

 

ctr. a little more compression.

 

Either the P30's or ITR pistons. The P30's will work just fine. CTR's will make the compression ratio close to 13:1 and you probably wouldn't be able to get away with that high compression with pump gas. I would shoot for a 11-12:1 compression ratio with that setup.

 

go with jdm itr pistons with gsr rods add some arp rod bolts. if you use ctr you have to mill your head which you probably won't. jdm itr are safe. i'm usin jdm itr piston in my car

 

yea im going to be using 93 pump gas, and im loking for like 12:1 compression, maybe 12.5:1 but nothing more than that. I was thiking about just using the jdm itr pistions, but i wasent sure witch pistons would be best for my set up. And how much power to you guys think ill be making?

 

you can you jdm itr piston if your plannin to tune your car , you just have to tune your for 93 octane. you planning to use flat surface valves

 

yea flat face valves

 

you'll be almost 11:8.1 cr

 

okay thanks, any one else have any opinions?

 

ctr in a gsr will be over 12:1 for sure. pretty close to 13. i would recommend o/s itr . good power , good compression, great street gas motor. p30 would be awesome as well.

 

if i were to put itr pistons in a 96 <U>USDM</U> gsr (stock CR 10.0:1 i believe) with in/in mani/TB/header/exhaust and cams, would i have problems. Plus i also have a mugen hi-comp headgasket(raises comp by .4 cr)i think with the headgasket my compression should be like 10.4:1. but if i put the pistons would i have and fitment or valvetrain problems?? and also could i use regular pump gas?? any help is appreciated and i dont know but would using underdrive pulleys help me gain power??

 

11:8.1, Nice.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 401tuner &raquo;</TD></TR><TR><TD CLASS="quote">yea im going to be using 93 pump gas, and im loking for like 12:1 compression, maybe 12.5:1 but nothing more than that. I was thiking about just using the jdm itr pistions, but i wasent sure witch pistons would be best for my set up. And how much power to you guys think ill be making?</TD></TR></TABLE>

go with jdm itr pistons, and with your setup I would guess around 180-190whp... it all depends on how good you get the car tuned.

 

Sounds like the same set up I'm currently working on..... From my research though, people including tuners would rather see people use itr or p30 pistons on a gsr just because they said you can tune it out more. I'm still going with jdm ctr oversized pistons and hopefully find a tuner who can set it up so I can run on pump gas. We'll see though