for a vortech V3 making like 13 psi what size should i go for a test pipes and dual exhaust???

 

3" single or 2.5" true dual.

 

Dont base your exhaust size on your boost pressure, base your exhaust size on your power goals?

but conway is right...3"

 

I run a dual 2.5 to 3 inch exhaust (Motordyne TDX) with my V3 at that PSI personally. Never ran a single exit before but I read that you can loose some low-end to midrange power but get great gains on the topend.