I am thinking about getting a bigger down pipe for my greddy kit (95 single cam vtec, greddy tdo4h turbo) the down pipe that comes with the kit is tiny. Anyway my question is if my catback exhaust and test pipe are 2.5'' in diameter is there any advantage of having a 3'' down pipe or should I just get one that matches my piping diameter? I know down pipe diameter can effect gas flow greatly, but would an over sized dp work better or just cause the bottle neck effect?
-Derek-
.afterdark.

 

i would probably run a 2.5" down pipe for that turbo, it is on the small side and 3" might be a bit on the overkill side. a while back i had a 2.5" downpipe made up for a 1st gen dsm fwd and it made a huge difference and that turbo is a lil larger that the td04 that comes with the greddy kit