exhaust

[93turbo_animal]

Ok I am thinking of changing my exhaust and wondering if you really need to upgrade the downpipe if all your planning is a chip or tuner. I can see why we need to on the IDI and the OBS psd's but the down pipe on my 03 looks like its already the same size as what I upgraded to on my 96

 

[BJS]

from my understanding you do not need to upsize the downpipe on a SD truck however the big restriction in the SD trucks is the cat (if equipped) and the muffler. They went from a straight through design on the OBS trucks to a convoluted path on the SD.

 

[CSIPSD]

A 4" down pipe will help as well, its not NECESSARY but it does help.