"Real" gains from exhaust?

[Niki]

I'm only going to do an exhaust if it's a definite gain in performance and economy, the truck makes enough noise as it is . Is a complete 4" system going to be any better on a truck w/ stock turbo/injectors than just a straight pipe? For that matter, does a straight pipe do anything? At what point(turbo, injector, pump) does an exhaust become a necessity? Thanks-Nick

 

[McLaughlin]

I didn't see much improvement on my second gen when I had my turbo back 4in installed (turbo spooled up faster). Fuel mileage was about the same. Power didn't seem noticably different. Noticed more imporvement with an injector and fuel plate swap.

 

[rlyons]

A straight pipe or oversize exhaust will lower your EGT's when increasing your power levels. At stock levels you will only gain exhaust noise. That is not a bad thing though.

 

[JLEONARD]

When I installed the 4 inch system (w/3 inch downpipe) I saw a 3 psi gain, much quicker turbo cooldown time, much quicker spoolup. And that's with the muffler in the system as well.

My truck is pretty quiet really. No drone at all on the highway.

I think I already had the performance injectors though.

Jay