Different Donaldson Muffler (M091046)

[TexAndy]

Ok, so I've been looking at buying a muffler for my deuce for awhile now and I really love the work some folks have done here giving their reviews of various mufflers.

Originally, based on the reviews of performance I've seen here, I was going to buy the Donaldson M070028.

But then I got to worrying about back pressure. Does better flow = less back pressure? If so, why not the M091046?

http://www.donaldson.com/en/exhaust/support/datalibrary/056799.pdf

On page 3 it lists three different mufflers of Style 1 (inlets on center) with 3.5" inlets. The M091046 has 25% better flow... and better noise attenuation listed.

The big downside I see is size. It's fully 7 inches longer and 2 inches wider.

Ok, two downsides... cheapest I can find the m091046 is for $131.56
About double the price of the m070028

 

[dozer1]

I think your biggest problem with that muffler would be the 2" bigger diameter. Already @ 7" the Donaldson M070028 required a slight mirror bracket mod for me. (see post #25 on attached link) http://www.steelsoldiers.com/deuce/54990-muffler-installation-db-comparison-3.html I imagine it could be done if you dont mind the extra work. At the time of the other thread, I was trying to coax someone into buying a Donaldson M070050 . It was like 6" longer and had a little higher flow ratings. I dont know if anybody tried it, but I no longer see it listed on the link you posted.
Now I see the M070050 listed 2nd from the bottom on page 55 of your list. They have NPT by the inlet and outlet diameter. As they say in the muffler business, that has me baffled. What does the NPT mean?

 

[dozer1]

Looking at my own picks on the other link and refreshing my memory, I would highly recommend sticking with M070028. Size constraints would very likely be a problem with the muffler you listed. I personally believe that the M070028 has ample flow and you will be happy with it.

 

[shenkmen]

Tex, I approached the muffler install the same way you are. I decided to keep it simple and go with the M07002. I'm glad I did as it...

1. Was easy to install. You can reuse the top clamp/mount point and add a new clamp to the bottom.
2. Looks good. I cut the top stack so the assembly is the same height with the muffler installed. I also looked at pics from other installs and did not care for the look of taller mufflers. The M070028blends right in with a coat of high temp paint.
3. Sounds good. Guessing it decreased the sound by 50%. Allot less yelling in and around the vehicle. The neighbors and wife are happier.

 

[goldwing2000]

Now I see the M070050 listed 2nd from the bottom on page 55 of your list. They have NPT by the inlet and outlet diameter. As they say in the muffler business, that has me baffled. What does the NPT mean?

That would be National Pipe Thread. Apparently it's a muffler that has HUGE threaded ends. For industrial applications, I would assume.