b16a eagles rod, cp pistons, gsr cams, skunk2 IM. that's about it for the setup.
how do i pick the right sized throttle body? is 68mm fine?

 

Its a waste to run a TB that's more than a few millimeters larger than your intercooler piping. I could reference my list of flow rates, but i dont care to type a lot right now.

 

edelbrock 75mm boy!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NA_B18C1 &raquo;</TD></TR><TR><TD CLASS="quote">edelbrock 75mm boy!!! </TD></TR></TABLE>

That may be a good suggestion, but the fact is, if its too large, it may actually hinder performance. The choice of what size throttle body is determined by the intercooler piping, flow rate of the turbo/engine, and intake manifold choice. If one was to go from a 2.5" intercooler pipe to a 75mm (2.95") throttle body, then back down to an intake manifold with a small plenum, the only thing you're going to see is turbulent flow through the throttle body. The best way is for the air to make a smooth transition from IC pipe, to TB, to IM, to engine...

 

so i have 2.5 piping. what size is skunk2 1st gen IM?

 

Well if you're running 2.5" IC piping, then a throttle body in the 64-68mm range will work just fine for you without being too large.