What would be the advantage of this and what is the compression ratio?

 

ttt

 

B18C block meaning JDM Sir-G?

Or the JDM ITR?

 

Yeah b18c=Sir-G or b18c1=GSR. Not ITR!

 

There is no advantage in C/R if you are tryin to boost it up a bit.. As in for NA purposes... The B16/ITR (PR3) cylinder head has a combustion chamber volume of 42.70cc's, the B18C1 (P72) has a CCV of 41.60cc's.. The difference of 1.10cc's on a stock bore motor is enough to drop the stock B18C1 C/R from 10.0:1 to 9.80:1... It's what is known as a poor mans ITR motor... All it would take is some ITR pistons, slight port/polish, ITR IM and TB, and ITR cams to have a basic ITR motor... That's completely worthless to me tho.. If you really want to build a motor with that head for some reason either sleeve the block up and go with forged slugs or go all out with the OE components... ie.. CTR slugs, cams, etc.. I would just stick with the GSR head... I personally like it and the manifold better.. A lot of people don't but this is just my personal preference... Latez

 

i was reading some where that a b16a head is vary simular to a b18c5 only diffence is cams and the port and polish

 

Very true. The B16 head flows better, that's why the Type R used the B16 head over the GSR.

 

So you loose compression when you put a b16 head on a b18c1. Has anyone ever seen a flow test done on either heads?

 

I dunno but all i know is its a basic common honda fact that a B16a head on a usdm gsr block will lower the compression .2 points. Fact is fact...

 

Actually, if you replace your GSR head with a B16 head you'll lose 0.15 compression which isn't anything.

 

0.15-0.20:1 big deal that's not much difference... With a std bore it really is closer to 0.20:1 tho... Peace

 

There are a few posts about this. I have this combo and I love it. I do have PR3 (b16a) pistons though. My CR is 11.1:1. If you use a stock GSR block, the CR does come down to 9.8:1. It is better to change pistons in this situation. Some people prefer the PR3 (B16a) head and some prefer the GSR head, and its just that, preference. Both flow well, but I think that after port work, the PR3 head is better. Alaniz Technologies has some flow charts on this as well. If the PR3 head didn't flow better, why would they use it on Type-R motors? B16A, B16B, B18C5 motors all share the same head, the R heads are ported, have better valvetrain, cams, and intake manifold though.