Muffler replacement options MCI MC9 6v92T

[neoneddy]

I just got off the phone with C & J Bus repair in Bloomington, MN about a muffler.  Seems they are also trying to source these.

Also I just purchased my bus shell, so I've been getting used to everything.

I managed to back over part of a stump and what was left of my rusting  muffler cracked off, it was toast before, but now I know for sure.

I've been digging around, it seems like there is a company Donaldson that makes a variety of mufflers, but I'm not sure which would be the right one.  Maybe thats up to me to to fabricate  a workable one in there.

I've seen some posts reference a M120131 Donaldson MUFFLER , I don't think that's my current configuration.  Any ideas?

[Stormcloud]

I recently replaced my MCI7 muffler with a Donaldson M120176, which has 5" inlet and outlet on same end.
I scored a new on the 'e' place for $100. I would gamble that yours is the same part number.

Fairly easy to install.....I had to make a new 5" turn-down to replace the 4" that was originally on the bus.

Mark

[neoneddy]

Thanks, by  "Turn down" do you mean the down pipe from the turbo or the  exhaust tip?

In the mean time I have been doing some sleuthing here.  Called Donaldson, and they came to the same conclusion, this is the right muffler.  I'd recommend searching on eBay or Google shopping for one retail.

I also called C & J Bus repair, they did source a bunch more today and will have some in stock if anyone else needs one.

[B_K]

You don't need no stink'n muffler, just put a resonator on it and run a straight pipe out the back!
  BK 

[Jim Eh.]

Another possibility is a Nelson Global muffler P/N 86121M

As with the Donaldson muffler, new hangers will be needed (probably rotten anyway) as they are 10X15 and from what I remember the MCI muffler body is a fair bit larger.

[luvrbus]

Another possibility is a Nelson Global muffler P/N 86121M

As with the Donaldson muffler, new hangers will be needed (probably rotten anyway) as they are 10X15 and from what I remember the MCI muffler body is a fair bit larger.

Wasn't the MCI muffler a Nelson made muffler I know they are a heavy sucker

[Stormcloud]

The `turn-down`is the outlet tip.  The original muffler had a 4 inch tip that had been smashed a few times ( not by me ) and they big truck shop here wanted a stupidly expensive price for a 5 inch. I bought a 5 inch 90 degree pipe and cut it on the bend to make my own. It looks and works fine.
I used the original hangers to support the muffler; they were in OK condition.
..and yes, it was a tad heavy.

Mark

[Jim Eh.]

Wasn't the MCI muffler a Nelson made muffler I know they are a heavy sucker

Probably was OEM. However, even a Nelson dealer cannot order proprietary parts from Nelson. Contract agreements mean only MCI can sell MCI mufflers.

[Scott & Heather]

Ask Sean shanks (seangie). He put on a simple muffler that sounds really good. Mildly throaty and just nice. It was cheap and easy to install.


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[TomC]

I'm running the M120131 Donaldson muffler with my 8V-71 turbo'd engine. This muffler is a free flowing "turbo" muffler and sounds great. I like it so much, I'm going to use another one with my truck conversion with Cat 3406B. If you can use a muffler with the inlet and outlet on the same side... Good Luck, TomC

[Iceni John]

I also have the Donaldson M120131, and as Tom says it sounds good.   My bus originally had the Nelson 86121M according to my Crown Parts Catalog  -  I don't know if other there are other makes of 10" x 15" oval mufflers with 5" inlet and outlet on the same end.   The Donaldson has less back-pressure than the Nelson, and its sound attenuation is 8 to 12 dB.   If you can fit it in your MCI, it may be easier than trying to get an MCI-specific muffler.

John   

[neoneddy]

Thanks everyone, this has been very helpful.

I am concerned about external noise.  I love the sound of my DD, but I want to be courteous as I can of our neighbors.

So, what's the Pros and Cons of the Donaldson vs Nelson?

[Oonrahnjay]

... I want to be courteous as I can of our neighbors.
So, what's the Pros and Cons of the Donaldson vs Nelson? 

    In my opinion (yeah, I know what it's worth ...), how you choose to use your right foot is a lot more important than the manufacturer of your muffler.

[neoneddy]

Well, in this scenario it would be fast idle, so I don't think my foot would be involved too much.

[Jim Eh.]

Muffler noise and performance work a lot like build time and money. Sometimes they even out ... but rarely.