I am building an all motor B18C1 with a fully ported/polished GSR head, ITR cams, portflow valvetrain, I/H/E, hondata s200, skunk2 IM, fpr, ...now as far as the bottom end goes, I am contemplating on either the oversized JDM ITR slugs (11:4:1 cr) or using oversized CTR slugs (12:1 cr). The question is will the hp be that much greater going with CTR's? (Not sure if the extra power is worth worrying about valve clearance and octane requirements) Also, will 310 cc injectors for this setup be overkill with the hondata? (270's are the same price as 310's so i dont want to have to buy injectors later on if I decide to go 2.0) Thanks and input is much appreciated!

 

1) IMO, if you are using ITR cams it is not necessary to use the CTR's, considering they run well on USDM's w/ 10.6:1 and on JDM's w/ 11.1:1. Also, you are in Cali. and can only get 91 octane, so that should be considered, although I don't know how much of a difference that will make since I get to use 93 on the East Coast and my 12.4:1 .

2) 310's will not be too much.

 

By going with the CTR pistons you will probably gain an extra 5 hp or so. If you have good tuning you will be able to get away with the 12:1 but you are on the edge. 11.4:1 would probably be better if you are too worried about detonation.

Since you have the Hondata system, the 310's probably won't be overkill since you can adjust them.

 

With Hondata you would have no problem running 13:1 compression on 440's on the street all day long with stock timing on 91 octane. All about the tuning. Now whether the ITR cams would make power with that set-up is a little tricky. Me personally same money go 12:1 with Hondata.

 

I would go with the CTR pistions since they are about the same price. Yes you will make more power throughout the entire powerband NOT just in the top end. i personally would go with 12.1cr because we have 93oct up in MN.

*i would get the 310 over the 270cc. Don't worry about it so much since you can fully tune it w/ hondata

 

I believe if you run a basic all motor or mild boosted system, Hondata recommends that you run a RC 440 injector.

Stay away from 2 or 12ohm independence.