I called my local Fleetpride dealership and gave them the 51" Donaldson p/n and they crossed it over to the Fleetpride p/n of M4490 (Nelson equivalent). Ok, I went to pick it up and it has the baffles in it.....I thought no big deal.

I installed the muffler, then came on DTR and discovered that I apparently got the incorrect muffler .

I then went to Cummins Filtration's website to compare flow rates of the Nelson w/baffles -vs- the non baffled Nelson. Anyway, the baffled Nelson (86713M) flows 1450 CFM in 2 inches of mercury and 1750 in 3 inches of mercury. The non baffled Nelson (86131M) flows 1670 CFM in 2 inches of mercury and 2000 CFM in 3 inches of mercury.

Ok, here's my question.....does it really matter with a stock truck if it flows at the lower CFN numbers (baffled Nelson) -vs- the slightly higher CFM numbers (non-baffled)? My main goal is to remove the restrictive stock muffler and reduce EGT's.

 

It's still probably a lot better than stock. My 03 muffler had 3.5" stubs but they choked down to 3" just inside the shell. What does your stocker look like inside? Craig

 

I don't know...I haven't opened up my stock one yet.

I'm probably overreacting to the whole baffle thing anyway. I'm certain that in order for it to ever be viewed as restrictive I'd have to add quite a bit more power. By that point, I'd probably need to move to a 5" turbo back system anyway

 

Check out this thread I did a while ago.

https://www.dieseltruckresource.com/...d.php?t=130323