On an SR running a T25, what would be a decent size for the IC piping? Ive heard 3" would cause too big of a drop in pressure? Is this true, or?
yeah, 3" would be huge for “normal” power levels(200hp-400hp)
I think greddy kits have 1 3/4" hot pipes, and 2.5" cold pipes? something like that anyway. if you go too big you loose pressure and air velocity(torque).
I went with 2 inch on hot and cold pipes and it has been working great for me at 12 psi.
Pm’s ya back.
Just make the transitions smooth.
Cold side on my greddy kit is 2.25, hot is 3
What kind of kit do you have?
Or is it custom made? If so, who made it?
2’’ and 2.5 would be best for response. Im kinda regretting having gone 2.5 and 3…I hate the fact full spool come on so late @ 3000RPM.
GO NA … dont worry about late spool or even supercharge it …
turbo lag like 3,000rom is not bad at all dude … that is like stock on sr20/ca
Take a look at the exit of the compressor side of your turbo… then think about how big a pipe you should use. 
No bigger than 2.5" for sure. I usually go 2" hot and 2.5" cold. I can do it all for you if you want.