Anyone know if I swapped out the gsr pistons for USDM type r pistons, which will raise the compression from 10:1 to around 10:8(gsr higher compression head) and along with a mild port and polish with skunk2 stage 1 cams, would pass CA emission? If not, is there anyway to pass the emission? like lean out the fuel with fuel controller or putting on a thicker head gasket etc.. Also, what would be an ideal compression ratio for street daily driven for all motor and wont reguire any octane boosting??? Does anyone have prices on a mildly built gsr head? mildly as in a bit more agressive port and polish then a type r head. thanks

 

I would think it'd pass, probably be close. The USDM ITR has 10.6:1 compression, so the .2 higher of the ITR pistons in the GSR won't really affect much, and the stage 1 cams are CARB legal, so it should pass You'll be fine on pump gas too.

 

how much power do you think that higher compression ratio is worth? just curious

 

So it should be close? but the motor is goin to be smogged as a b18c1 which in stock will have only 10:1 and im raising the CR to around 10:8. Are you saying that the ITR 10.6:1 is pretty close to the stock gsr CR and wont effect much of a difference in emission? What about port and polish, would that take any effect in emission? Also, planning to throw in the skunk2 IM with the setup, is that also carb legal? From higher CR you could possibly gain gain 10-20hp along with good flow like cams and the skunk2 IM. Hopefully this setup goes through.. thanks

 

Skunk2 IM is not currently CARB legal, but they are working on it. Going from 10:1 to 10.8:1 won't give you a huge increase, but it will a little. I don't remember the equations for power increases from compression ratio increase. I was saying that the stock itr of 10.6 is pretty close to what yours will be at 10.8, so that won't be much of an issue passing smog...the ITR passes cleanly. P&P head really won't affect your emissions much either.

 

sweet, Even a valve job wont effect the emission much right? Any suggestions,comments, etc on my setup?
b18c1 with rebuilt bottom end with USDM type r pistons, port and polish head along with 3 angle valve job, skunk2 stage 1 cams, skunk2 retainers,valve springs,skunk2 IM, compression ratio 10.8:1
Should i go with a higher CR? or is 10.8:1 enough? CTR cams or skunk2 stage1 or any others reccomended?
Or Should i go with a complete type r head setup, with skunk2 cams,retainers,valves springs??? thanks

 

10.8 is fine. I'd keep the GSR head and p&p, and with skunk internals you now have a head better than the ITR. Should see some nice numbers with that setup...good luck.

 

hey thanks again...u the man!!!

 

dude if your gonna do all that ****, dont get stage 1s. it would be a waste. go stage2, theyre so much better than stage1 or ctrs. believe me you want stage2. if your worried about passing smog then get the skunk2 stage2s with a stock idle lobe. that way your mileage wont be affected, or your low end power for around town driving. just when you wanna go fast, you drop a gear into vtec and BOOM, stage2 power right there.

 

More&Faster:so you're saying if i could get the stock idle lobe for the skunk2 cams, only the vtec lobes have the agressive duration and lift, but anything else when not in vtec is pretty much stock duration and lift? I'm not really familar on how the aftermarket cams go in conjunction with the vtec lobes. On aftermarket vtec cams do they alter all the lobes including the non vtec lobes? I mean is there any point to increase lift or duration on the non vtec lobes? because in vtec that is where the power is, isn't it? and the more flow you have in lower rpms will hurt the low end power right? Like you said More&Faster i can get stock idle lobe and just have the agressive lift and duration on the vtec lobes. Or if im thinking right, the altered agressive lift and duration in the non vtec lobes give a smoother transition in power to the vtec lobes..Could someone clear me up on this??? I would appreciated it, thanks