i am building my ls/vtec high compression/ nitrous motor and i have a couple questions for the honda tech's out there, i am going with a 82mm b18b1 block and im running ls crank and rods, also i have a gsr head i bought off of bigmike here on tr and now im stuck on which pistons to go with? now i heard anything over a 12.5:1 compression ratio isn't a good idea to run on pump gas so i am going for about a 12:1 or so so when i put my info into a compression calculator on c-speedracing and i put some pr3's on it my numbers come out to 12.135:1 with a displacement of 1880.235 cc's but will the pistons hit my head? i heard from a pretty reputable builder here on tr that they will but other tell me it wont? lmk tr i need to get these pistons ordered asap since im taking my motor to the machine shop this weekend lmk thanks tr, john

 

Go for the P30 JDM B16 Pistons. If your using LS Rods you shouldn't have nothing to worry about. I'm not too exprienced on it, but i'm building one right now and it's going fine. you will be able to press them right onto the LS rods. My friend Also done a LS/VTEC with CTR pistons with a higher Dome height and He used a GSR head and had no problem of the piston hitting the head. It basically based on Measurements. You'll have to worry more about the Spark plug hitting. I hope i answered your question.

 

you'll be fine either way you go...you only worry about clearance problems w/ BIG cams and BIG compression....i have ran almost every piston you have stated, i even had a set of endyne rollerwaves that were damn near identical to a CTR...i have never had any problems.

if it was me, i would go USDM ITR's....that way the compression isnt outstanding.. that way you dont have to run 93 all the time...but im a cheap bastard.

 

^^That you are.

 

lol its good but since im going to be using 93 all the time anyways would it be better to run usdm b16 pr3's or jdm b16 p30's lmk what you think tr

 

either are good its only like .2 diferance.

 

yeah but is there any clearance problems with the jdm p30's? lmk asap

 

+1 to that

 

last time i checked oem pistons only go .25 over unless RS makes 82mm pistons your gonna have to go with aftermarket psitons

 

yeh i am going w/ nippon pistons... why i heard they were good pistons