Muffler replacement

[Teich]

All i have is a construction drawing, muffler is 8'' wide 11" tall mounts are welded on inlet and outlet are 4" extend to about the middle has two baffles these have a 3. 5" holes the inlet and outlet pipes are perferated as the Donaldson can't tell how ends are made. It is sold as a direct replacement for 2004. 5 up truck. No idea of flow or noise reduction. I would post the drawing but haven't figured that out yet Laurie

 

[RBellah]

Laurie have you got the muffler yet? Waiting to hear what is sounds like and how easy it is to install. Let is know

 

[Teich]

New muffler hasn't arrived yet, hangers supposed to be same as original, will have tomake a new connecting pipe from turbo dn to muffler doesn't look to hard. Photos when this starts Laurie

 

[Teich]

Muffler got here last week,been busy fixn' the tractor,winter's hereand have to move some of it. The muffler looks nice should fit easy, that will happen in about a week, vacation trip. Here are some photo's:

 

[RBellah]

Looks like a chambered muffler. How does it sound?

 

[Teich]

Yes it is chambered, two baffles 3. 5" holes inlet and outlet are 4" open on inside end just passing each other in the middle. Just finished the install tonight,will test tomorow if we don't have our freezing rain !! Will post after the test run. Laurie

 

[RBellah]

Do I hear some Music or is that the Purr from the Cummins Turbo?

 

[Teich]

Well I had truck out for a short run to much ice to really test, music... yes turbo... yes seat don't know yet, in the cab it is quieter out side it sounds good I think the truck pulls the same but too icey to be sure. I think I will like it but need to pull a hill or two to be sure. The muffler did fit nice had to make new pipe down pipe to muffler, has to drop approx. 1. 5" Laurie

 

[Teich]

Test run happened and it was good nice in the cab wife happy sounds good at the back of truck seems to pull the same but have to wait til summer to put the trailer on. I think it may be a little louder than the oem, hard to tell had so many mufflers on! Laurie

 

[JPul]

I pulled the RV out of storage yesterday and am pleased to report that there was no drone at 2100 rpm with the Donaldson muffler. You could certainly hear the growl and even under no load, there is a slightly higher noise level but overall, I'm very satisfied with this muffler. If a clamp with hangers could be easily purchased separately, this would be a very good upgrade but the hanger issue needs to be resolved to make this an easy retrofit.



Regards, John

 

[TObrien]

Lot's of good info in this thread, thanks guys. I replaced my stock exhaust two years ago when the front pipe rusted off of the muffler (03 3500 ST QC SRW 4x4 Auto 3. 73 Van Aaken Smartbox). Had to pull the 5th wheel back from Maine to CT sans muffler. I got the MBRP 4" system from Geno's only to find that the drone and noise in the cab is virtually the same as the straight pipe. Not terrible driving around unloaded, but pulling the 12k trailer requires ear plugs. I saw all the information on the Donalson's and looked into it. With so many choices I started asking questions. Donalson said they needed the exhaust flow rate in order to properly size the muffler. So I called Cummins and they said they need the engine serial number to give me the flow rate, so I gave it to them and they said my engine exhaust flow was 1052 CFM. Now back to Donalson- Their catalog lists the flow rates for their mufflers at 1"Hg, 2"Hg, and 3"Hg back pressure. The technician said that to have a reasonable attenuation (muffling), you need to chose a muffler with 1. 5"Hg to 2"Hg back pressure at the engine's rated exhaust flow. He stated that if the muffler's back pressure is less than 1"Hg (at your engine's rated exhaust flow) then you should not expect to have any noticeable attenuation.
I have seen several posts that the say the Donaldson is quiet, as well as several that say it is too loud- some say the 51" eliminates the drone (as opposed to the shorter versions) and some say it doesn't. My question to the group is, has anyone sized a Donaldson (long or short) to their rated exhaust flow at 1. 5" to 2"HG back pressure, and had good results? I'm just looking for a stock-ish noise level. If I knew then what I know now, I would have just bought a replacement stock system.
Thanks again for your expertise.

 

[BlackBullit]

Just wondering what exhaust you went with, Prairie Dog? I'v been thinking about doing an exhaust on my '03 before i go on a trip to KY in about a month. What brand would be good? I don't want it very loud. If it would be just a bit louder than stock would be OK.

 

[JPul]

TObrien,



I believe that expansion volume has a significant influence on drone. With the MBRP system, the OD of the muffler isn't a lot more than the 4" piping so not a lot of expansion volume. When my muffler rotted out, I wanted a muffler that would replace the stock but have similar volume characteristics to stock, but at the same time, be a little freer flowing to help with EGT's. The offset donaldson muffler I chose, fit that requirement. Donaldson does have some longer offset mufflers that could be used, given the approx 9" of pipe on the front end of the stock and some of these have flow characteristics and attenuation numbers that would provide a lower noise level but overall I'm very satisfied with the muffler I used. Your muffler needs may be different based on replacing the straight muffler as used by the MBRP system but the higher volumes of any of the Donaldson's should reduce drone a bunch. The offset M110012 should fit as stock replacement and provides decent attenuation, the 110189 even more attenuation but, being longer, it may require cutting off at the CAT outlet pipe. The straight through M100464 is the only one that provides more attentuation than what I used but the flow numbers appear restrictive to me and that muffler is long.



Hope this helped you a bit.



Regards, John

 

[Prairie Dog]

Just wondering what exhaust you went with, Prairie Dog? I'v been thinking about doing an exhaust on my '03 before i go on a trip to KY in about a month. What brand would be good? I don't want it very loud. If it would be just a bit louder than stock would be OK.

Me? I haven't replaced it yet but that tail pipe is looking like it may blow out at any time. All this talk about backpressure and attenuation has me head spinning!
I really don't want to replace the muffler only to find the new one isn't any better. Maybe I want too much - better flow and less noise/drone.
From what John (above) says the Donaldson 110189 may be the prefect app. since I don't have a cat in the way. But, with an attenuation of only 1" HG at our flow rate, it doesn't sound like it would "muffle" much.

Scotty

 

[JPul]

PD,



The 110189 has one of the highest attenuation ratings on the list of 4" offset mufflers. The 120197 has higher attenuation numbers but quite a bit lower flow numbers. The 101168 that I used is not bad for noise but the attenuation numbers are much lower and the flow is higher. I think the 189 would be a nice replacement muffler if quiet was desired and the room for a 36" muffler was there (no CAT). but there is still a bit of money and effort required to confirm that, with the risk that it isn't quiet enough. I think the 197 is too restrictive but should certainly be quiet.



Regards, John

 

[TObrien]

JPul,

Thought I'd report back on the Donaldson installation after my annual trip to Maine. I decided to go with the M100466 which is the 10" diameter 51" muffler, 4" no offset (to fit the MBRP pipes), even though the flow numbers were higher than what the Donalson Tech recommended (i was concerned about egt's). This muffler completely eliminated the drone and cab noise. The noise level in the cab is about what I remember stock being like, but the bark outside the truck is a little louder- no objections. Since I had a rinky dink dB meter app on my phone I ran a test with the MBRP, then again with the Donaldson, pulling the 5th wheel full throttle. MBRP = 80-82dB, Donaldson = 68-70dB windows up in the cab. Since I have an '03 with no cat concerns there was no problem fitting the long muffler. I used 2x P206519 Donaldson muffler hangers with nut and bolt into the original rubber isolators at the rear of the muffler, and a 4" pipe hanger at the front mounted to one of the seat frame bolts- had to get a longer one so I could pick up the hanger. A little vibration in the seats now at idle, but it's OK. Besides, how much time do we spend at idle?

Thanks for the help/advice.

Terry