OK, so here is a question for ya'll. I am looking at quieting down my stack set-up a little bit. If I put a diesel muffler somewhere between the downpipe and the 90* elbow going up to the stacks, am I going to have to worry about EGT's going up due to lack of flow (if at all) Also, does anyone think that might really quiet things down?

If your asking yourself why does he want to quiet them down, the answer is that I am moving locations for work, and I can deal with less than 2 hours of stack sound, but my trip may go anywhere from 3-5 hours.

 

You don't say what size exhaust pipe you're running so I'm assuming 4".


With the above, we're moving right at 1332 CFM through the exhaust system at 3000rpm.

The following muffler is the style 5 type (in/out on the same end). That will allow you to park the muffler under the bed with plenty of room. If you want to go full 5" dig here ~ https://dynamic.donaldson.com/webc/W...?section=10215

4" in x 5" out ~ https://dynamic.donaldson.com/webc/W...15&item=166044

It should hush things up nicely without undue restriction.

Hope this helps, gotta run . . . . . . . .

 

Many truck parts places sell stacks with mufflers in them already. I put a set of 6" stacks on an older W900 we were doing some work too and threw the long mufflers into the scrap dumpster. You might have to special order them for your length and end shape (tip out, bullhauler, etc).

These flow plenty well and take the edge off the exhaust note. They are still loud. I think they are a good compromise of sound and performance.

 

If you want it real quiet, do what BC847 suggests.

Just to take the edge off it a resonator under the cab would work.

 

i put a muffler under mine the drone got worse but while i was checking things out i read that it was quieter in the cab if you take out the internal mufflers but did not try it i just took them off because i got overhead camper