Well after reading many post on what muffler to use. I wanted a muffler that had stock type quietness with maximum flow for lower temps and flowed well for future minor mods. I decided to research more and more and this is what I came up with.

I found that the 51"x9" Donaldson M090544 (same as Nelson 86131) that a lot of people were using had attenuation # 's of 13-18 and flowed 1638 CFM @ 2 HG and some said it was a little louder than stock.

I ended up using the 51"x10" Donaldson M100580 that has atenuation numbers of 19-25 and flowed 2215 CFM @ 2 HG and was said to meet some type of low sound standard. I did not realy care if it was a straight through design or not with those flow numbers, but found that it was a straight through design with a perforated baffle on the inlet end and was 5" in/out. I left the baffle in place as it flows plenty with it and I was again.......looking for quiet. With adapters to mate it to my 4" factory tailpipe and to my Kitty test pipe the installation went just fine thanks to a local friend at a muffler shop. I also install a 13" x 5" stainless tip to keep the black stain from reaccuring on the right rear bumper.

The sound is very quiet when cruising with a slightly deaper tone. The only time I really know I did anything to the exhaust is when I roll down my passenger side windows down and push hard on the go pedal.

For those looking for a quiet system that flows well I can say that this system has been wife ear tested (she was clueless that I had done anything to it) and passed.

I wish I could give before and after exhaust temps. But I will take everyones word that free flowing = lower temps. As for power.....seems no different. As for quicker spool up....seems no different. Will it fit with a Kitty....would be real tight with the adapters.

Disclaimer! Always put your kitty back on after your kitty test has been performed

 

I totaly agree with you on the donaldson/nelson mufflers. I see these guys paying $400 + for these high dollar hi-flow exhausts and then you read a post from them compaining about the horrible drone on the hwy.

My truck had a stright pipe from the previous owner doings and it was ok in the city but HORRIBLE on the hwy. But since I went to the 42" donaldson I have a nice low rumble in the city but I don't hear a thing on the hwy, except for the stereo or the wife nagging. Now if donaldson/nelson made a wife muffler they could make some serious money

 

Wife muffler! I could go on that new show American Inventor and make a million $$$$

 

how much you pay for it?

 

Muffler was $90.00 and each adapter was $13.00. I also used about 3ft ($13)of 5" pipe for a kitty test pipe and connection to the adpater to muffler outlet.

The layout result was adapter, 2ft 5" pipe for kitty test pipe, muffler, 4" section of 5" pipe, adapter, tailpipe followed by 5" exhaust tip.

 

When you talk about Kitty, I would assume the test would be giving it Exlax to clean it out so Kitty has some better flow. If Kitty has no flow, I don't car how big your muffler is, you accomplished nothing.

 

The kitty is still on the bench and I am testing it everyday The test pipe will remain on the truck until I have completed my bench testing The main point I was making was that without the kitty this system is really quiet and flows more than I think I will ever need it to.

 

2" mercury isn't even 1/10 the atmospheric pressure at most places at sea level. 1 atmosphere is over 29" Hg isn't it? Not bagging on Donaldson or the thread but why test at 2" Hg?.....anyone?....just curious.

Mike
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I was using the wrong number. It is 2215 @ 2 HG which is still more than what the m090544 muffler flows and is quieter. I have read other posts that say to use the MR (med. range?) column for general flow comparison. Someone in the know please chime in.

M100580 specs

A - Inlet Diameter (Inches): 5
B - Body Diameter (Inches): 10
D - Overall Length (Inches): 51
E - Outlet Diameter (Inches): 5
Rated Flow LR (CFM): 1565
Rated Flow MR (CFM): 2215
Rated Flow HR (CFM): 2530
Back Press LR (In Hg): 1
Back Press MR (In Hg): 2
Back Press HR (In Hg): 3
Attenuation (dBA): 19-25
Product Type Description: Muffler, Round, Style 1
Primary Application: SVV 4CYC LARGE BORE TURBO ENG
Application Note: MEETS 88 NOISE REQUIREMENTS


M090544 (same as Nelson 86131m)

A - Inlet Diameter (Inches): 4
B - Body Diameter (Inches): 9
D - Overall Length (Inches): 51
E - Outlet Diameter (Inches): 4
Rated Flow LR (CFM): 1158
Rated Flow MR (CFM): 1638
Rated Flow HR (CFM): 2006
Back Press LR (In Hg): 1
Back Press MR (In Hg): 2
Back Press HR (In Hg): 3
Attenuation (dBA): 13-18
Product Type Description: Muffler, Round, Style 1
Primary Application: OFF ROAD APPLICATIONS

 

Towed with this setup today (3000 lbs) and no drone lugging up grade or at anytime on freeway. Have ran 55-80 mph while empty and no drone - very quiet.

 

i bought my donaldson 41" muffler at a local big rig shop for 61.00 bucks.

 

I have the 36" Donaldson of the same series and it is great cruising, gives you a little sound when you get on and according everyone that has heard it, sounds good. Gives the big rig sound to some extent but is still pretty nice and quiet when towing unless you really hammer on it, and even then it is decent.

At 2200-2400 RPM you get a little drony hum noise, but I had that from the factory to a slightly lesser extent. When we brought it home new going 75 on interstate I commented that it sounded like you were "sitting on an airplane".

This truck is almost always hooked to a trailer, and when used, it is usually going a fair distance, so I wanted something that wouldn't be loud and irritate me on long trips, and this unit has fit the bill nicely. I just happen to have one of the trucks that likes to buzz a little at certain RPM levels.

 

I can relate to the sitting on an airplane sound. That is kind of what I hear. The whine of the turbo and the hum of the engine.

 

I wanted to go with the longer one but they didn't have one here locally I could get. I chopped the stock muffler 4 days after I bought the truck because it sounded like a gasser with a spark knock in it when it came home. There are times I wish my 36" Donaldson was a tick louder and gave me more turbo sound like I had on my PSD with the Walker BTM...and times when I wished it was a tick quieter, when I have 13K behind me and I have it hung at 2300RPMs trying to merge into traffic with a carload of people who just don't understand how a real truck is supposed to sound.

 

What is the difference other than the length 36"41"51" The amount of sound?
Joe Z