I just put a bid on a huge intercooler on ebay.
It has 3 in inlet and outlet.

I had originally planned on running 2.5 in pipe for the whole system. But is there any reason not to run 3in for hte whole system.

 

Are you going to be running a large turbocharger with decent boost levels? If so, then the 3" will work great.
If you are running a mid-sized turbocharger and lower boost, then you would probably be better off with the 2.5" or 2.75" piping.

 

As long as at no point in the piping you go smaller than the Turbo Outlet, - you're fine.

2.75 piping is hard to get (read $$$). You can get different sized transitions, that go from 2.5 to 2.75, 2.5 to 3.00, etc..

 

im going with the bnr stage 4, 60-1 compressor. 15 psi on 93 and 20 psi on 100

Im thinking 3in with that.

 

Sounds to be too big. I'm running 2.5" with a full 60-1 turbo, and many people seem to do the same. I think 3" is going overboard here -- you'll end up with more difficult pipe routing as well as higher cost and more lag most likely.

-Manolis

 

well I lost the bid on the intercooler anyways.

Anyone got a large style npr intercooler they want to sell. That would be perfect. I want to go overkill on this part.