High Flow Muffler for a 2004
Diesel Enthusiast
Joined: Mar 2007
Posts: 127
Likes: 7
From: Northern Va
Actually your exhaust "should be" 3.5" all the way back to the tailpipe. After a few inches of tailpipe it flares out to 4". I have read, however, of a few of the later 04 305HOs getting the bigger turbo elbow and 4" exhaust from the factory. Maybe you got lucky.....
Diesel Enthusiast
Joined: Feb 2009
Posts: 121
Likes: 0
From: pittsburgh
It is an 04 (build date is last quarter of 03), but it's got a 4" stock original exhaust system on it with no cat. I've got some sort of half-breed, mutt of a truck. When I originally bought the truck, I had trouble registering it because the VIN didn't compute as an 04. The other thing I've been told is it is basically a 3500 series but is listed as a 2500. I've got one ton springs on the thing. I'm thinking that as it came down the assembly line it was put together with a mix/match of parts before they switched over to the 04.5's. Damned if I know? Anyway, about my muffler question.....
Seriously, an tips, pointers, "I wouldn't do that if I were you"'s would be greatly appreciated.
Seriously, an tips, pointers, "I wouldn't do that if I were you"'s would be greatly appreciated.
Diesel Enthusiast
Joined: Oct 2008
Posts: 286
Likes: 25
My 04 305/555 has a 4" exhaust,3.5" down pipe and no Cat. Built 09/03.
Last edited by torqctd; Mar 28, 2009 at 01:11 PM.
Diesel Enthusiast
Joined: Mar 2007
Posts: 127
Likes: 7
From: Northern Va
I cannot comment on the HP increase either but I can attest to the EGT drop. When I had my 03 I pulled the elbow off the turbo and got a Banks 4" Downpipe. Once I installed that along with my 4" exhaust my temps dropped 100 degrees immediately.
I'm getting ready to do the same on my current truck except this time I'm using a newer 4" in/out elbow and a downpipe from a later truck. I'm also gonna use a 6.7 muffler and tailpipe and see how that sounds. It's a straight thru muffler so it should sound pretty good.....
I'm getting ready to do the same on my current truck except this time I'm using a newer 4" in/out elbow and a downpipe from a later truck. I'm also gonna use a 6.7 muffler and tailpipe and see how that sounds. It's a straight thru muffler so it should sound pretty good.....
