Hello H-T,

First a little background info. The motor is a B18C1 (GSR). The head is P/P, built w/springs and Ti retainers, but not milled (just a couple thousandths off to resurface). Cams have 11.8 mm of lift. The block is bored .25 mm over and honed.

I would like to have a streetable high compression motor w/200+ whp (road race/auto X on weekends - occasional drag). I know I can use the JDM ITR pistons and have a 11.4:1 C/R w/no piston/valve clearance issues. I would like to go higher though and I'm well aware that it can be done.

So I have a few questions for those who can answer:

1) What is the comp. ratio for this motor using CTR pistons? Streetable?

2) Will there be any piston/valve clearance issues using these pistons in this motor with cams that have 11.8 mm of lift?

I will have all of the appropriate components for a high comp. motor (VAFC, tuned ECU, J&S, etc., etc.). Any other comments are also welcome. Thanks.

-Shawn

 

hey - you can find lots on this if you search, CTR pistons in general are not that streetable, the CR is just to high -close to 12.4:1 in a b18c1 - i think, but i'm not sure), you might be able to get away with 94 oct fuel, as for the lift on you cams, im not sure (what cams are they), I would stick with JDM ITR pistons, i take it you have either an ITR intake manifold or a skunk2 mani, bored TB, fuel injectors, etc... (when you said you have all the components) - is this a daily driver - or just streetable?
Greg

 

I did a search before I posted - didn't answer my questions.

If I can get 200 + whp w/the JDM ITR piston C.R. w/all of the other components I'm using then I'll do that, but if not then I would like to go with a higher C.R. piston. The cams are Crower 63402's and they like high compression (I'm using Crower springs and retainers as well). With such aggressive cams the higher the C.R. the better.

I do have the Skunk 2 manifold, 64 mm TB, 270 cc/min injectors, adj. fuel pres. reg., etc., etc.

The car is going to be my "daily driver", but I like to have lots of fun with it on a "daily" basis too.

-Shawn

 

Anybody else who can help?

-Shawn

 

No hard core tuners here?

Oh well, at least the knowledge base here is better than a lot of other boards. Thanks anyway.

-Shawn

 

1. Yes you can get away with the higher comp of the CTR pistons and you have the J&S so that is a plus Ratio will be roughly 12.5 -12.6:1

2. No there shouldnt be but you should always Clay the engine just to check, if so you could use a thicker headgasket from Toda to knock the comp points down a few and make the extra space needed.

 

Thanks Mike! That's what I needed to hear.

-Shawn