Well im lookin into doin some Itbs on my gsr motor....I was lookin for some insight on compression....should i have the head milled for higher compression or will i be good w/ the stock gsr comp?

also cams just some stock itrs? or maybe like some skunk 2 st2?


rest of set up
jdm Type r header + CAT, es oval exhaust
tein, spoon, recaro.....

 

yeah im curious about the compression recommedations for itb's, im running 11.5 with stage 2 cams and i wonder if thats high enough?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ekfoe &raquo;</TD></TR><TR><TD CLASS="quote">yeah im curious about the compression recommedations for itb's, im running 11.5 with stage 2 cams and i wonder if thats high enough?</TD></TR></TABLE>

ITBs dont dictate what compression you need...cams do.

 

Compression/boost is needed for real performance with aftermarket cams, however... the cam is what's needed for real performance increments for ITB's a bad mixture causes backfiring out the intake... not pleasant... looks cool though haha

 

Well you should build the motor for a specific peak RPM or better yet an intended for use RPM range. If you look for some graphs of ITBs that float around here, you'll notice that they scream in the top end even after the cams max out their initial max RPM. Yet, low end shouldn't be affected with them either. So if you build the motor per say capable of 9500rpms with cams that peak that high with a regular manifold then the ITBs will add a nice little touch and may even create more power until 10000rpms. But, if you lengthen your powerband many other things have to be taken into consideration. The B18's 1.54:1 RR for one is made for a tad bit more low end torque than that of the 1.75:1 RR of the B16. So the B18 should be built with cams with a little more duration and less lift while the B16 on the other hand shouldn't have as much duration but more lift to create a nice amount of power. Spinning a motor high will create a lot of stress. Gearing needs to be changed, rotating mass needs to be lighter among other things. But, if done right then you shouldn't run into problems. These are just a couple things that I have gathered.

Someone please correct me if I am wrong.
-Mike