So with this truck (see signiture) that I'm slowly "tweaking" it has a bone stock exhaust system,will I gain much by simply cutting out the muffler and welding a straight pipe in its place?thanx

 

probably won't gain much performance with the rest of the stock pipe in there, but it'll sound a lot cooler

 

On 4x4 trucks the tailpipe is a restriction where it goes over the axle, it gets mashed down to 2.5" or so.

 

You might feel a little less turbo lag, but that's about it. It will help keep your EGT down and sound cool at the same time.

 

I noticed on my 91 W350 that the pipe was smashed where it went over the axle. Seems like the slight lift on the 4x4 should actually make it a little easier to get the pipe through there. Does anyone know why they crush the pipe?

 

my pipe is smashed around the t-case worse than the tailpipe....

 

I had a 3" straight pipe about 18" long from the downpipe connected to the front of a 14" Magnaflow non-restriction muffler, mandrel bent tail pipe for $236.00 complete with labor at a shop that does exhuast for school buses, and firetrucks. I wanted to go 4" but the price was $150+ more. My rig runs great, it's not too loud, has good acceleration (see intake below). Some say go 3.5", 4", 5". I'm not planning to turn up my pump, I'll keep injectors stock for now. I've heard some stories regarding a 'droning sound' at highway speeds with the 4".
Personal preference... Cummins put on a 3" downpipe/exhaust from the factory-It works for me
Patrick.

 

i got my muffler off. i skipped school one day toi go do it. now it sounds good. you can be idling and hear the echo off a building. and i can rev it up and everyone turnes there heads to see. it will sound alot better