I have access to both stainless 4" and mild steel (sch 8 or 10). Also have a wire welder.

I'm thinking about building my own and insulating it from the turbo to over the axle. This should do two things, keep the exhaust hot, therefor keeping velocity up, helping the turbo spool, and quiten things down a bit.

In looking at the down pipe it appears you need to cut a 90 or use a 45, then of course 90s and or 45s at the rear axle.

And what about going straight out the back with a turndown vs to the side behind the rear tire. I'm thinking simpler and prehaps a bit quiter. Just wonder why no one does this.

Thanks, RJR

 

i have my 4 inch going out the side and when they added a tip to it it got quieter inside. i have seen here on this page where a guy ran it out the back and took away the 2k rpm drone.

 

turn downs seem to make alot of noise in the cab to

 

Here check this out..
https://www.dieseltruckresource.com/...threadid=61905