Big Giant Donaldson Muffler installed today

[RTillery]

Thanks Jman. Went to Perfomance Muffler in Denver today and they put on my 51" Donaldson Muffler. Nice Folks. Scott was very cooperative and knew just what I wanted to do. I like the results. The muffler is at least as quiet in the cab but I am riding around with the right side windows down, bouncing the sound off of anything overthere. Sounds cool. The truck feels smoother and feels like it is running easier. I can hear the turbo winding up, but with the window down it has that big rig sound. Like my daughter says, If a semi and a pickup had a baby, that would be Dad's new truck! At least it sounds right now. Now if I can just keep the accelerator pump (right foot) from working so hard, maybe I can do a mileage check. Oo.

 

[boonsur]

I 'll ask the usual questions...



Does this go in the stock location?



Is it a straight-thru?



What is the p/n & price? How much additional plumbing did it take?

 

[RTillery]

It is mounted back where the stock one was but extends way forward. Body is 44. 5" long with overall 51". 9" diameter. Fit it right to the 4" over the axle piece. Adapted the 3. 5" to 4" at the inlet. Cost $65. Install was $75. Donaldson part # is MU90544. It is a straight thru but has a coned shape baffle about 18" down from the inlet. Going to do about a hundred miles tomorrow so will get a better feel for it then. So far I am very happy with it.

 

[BIG BOB]

How about an update?



I just ordered an 51" Nelson from FleetPride, $53 for the muffler and with shipping to my door it was $66.

 

[Matt400]

Sure would like to see a couple pics of the hanger points for that big torpedo!



I was thinking of getting the 51" Nelson by Fleetguard #86514M. Same thing but has a 5" outlet for a bigger tail pipeOo.



Found it here

 

[BIG BOB]

Before you installed the Donaldson, did you happen to look inside the muffler? Was it straight through or did it have a baffle in it?



How about anyone with a 86131M Nelson? Was there a baffle in the 4" pipe?

 

[BIG BOB]

Originally posted by RTillery

It is a straight thru but has a coned shape baffle about 18" down from the inlet.

Opps, I missed this.



How about the Nelson 86131M?

 

[RTillery]

Matt 400, don't have any pictures but the muffler shop welded a hanger towards the back similar to the original and put another one up towards the front that tied into the original pipe hanger bracket. Works great. I have a couple of hundred miles on it now and am very pleased with the quiet sound with just a little hint of what the mighty Cummins is doing.

 

[Matt400]

Originally posted by RTillery

the muffler shop welded a hanger towards the back similar to the original and put another one up towards the front that tied into the original pipe hanger bracket.

Cool, I was thinking that would be they way to go to just cut off the factory hangers at the old stuff, leave em dangling then fit the big muffler and weld the hangers where they fall.

 

[BIG BOB]

I installed the Nelson 86713M today, however before I did, I took a 1. 25" pipe and proceeded to enlarge a hole through the baffle. The baffle is made as part of the inner liner but bent or formed to form a 4 piece cone in the middle of the muffler. There was only small holes in the cone. By taking the 1. 25" pipe I make a pretty good size hole to open it up.



It is installed, throttle response is much better, and more power at higher rpm and speeds.



It's a little louder than stock, but you only notice it a low speeds. Cruising on the highway, hardly any difference from stock. I think I going to like this!

 

[RPosey]

muffler

Is it ok to weld with the computer hooked up? I need to attach a bracket to my frame crossmember and was afraid too.

 

[Matt400]

Re: muffler

Originally posted by RPosey

Is it ok to weld with the computer hooked up? I need to attach a bracket to my frame crossmember and was afraid too.

Gas weld= ok but electric weld you should disconnect the neg battery cables.

 

[RPosey]

Thanks for the tip.