Pics man! We need to see pics!!

MikeyB

 

All right guys, here is the low down on the M4490 FleetPride muffler.

I ordered one from FleetPride and just received it today. The Nelson part number is on the box and also the muffler is stamped with the Nelson part #. The part number is 86713M. The specs on this muffler are:

2" HG = 1450 CFM
3" HG = 1750 CFM

These numbers are according to Fleetguard's website.


Nelson Muffler Spec's

The thing that upsets me is that I ordered a Nelson 86131M, FleetPride didn't have any in Auburn, WA. but had some in Klamath Falls, OR. The sales rep in Auburn called Klamath Falls about the muffler. To make this story shorter, I called Klamath Falls and they said they had the muffler but it cross-referenced to FleetPride #M4490. Well like I said, I got the 86713M Nelson muffler.

Doug, looks like you are going to have to change your flow numbers on the M4490. Do you feel that this muffler will flow enough for a 420 HP Cummins?

I noticed that there is a baffle that restricts the flow of the 86713M. I was considering knocking it out so there would not be any restiction through the 4" pipe inside the muffler. What do you think about that?

I was going to put this on tomorrow, was pretty bummed when I saw the part number. What do you guys think, should I knock the baffle out and install it?

 

Bummer Big Bob.
I'm going out on a limb but it appears from the spec that the only difference between the two mufflers is the baffle. A slight decrease in flow rate with the baffle. And it's probably quieter.
What you could do is have the muffler installed but don't weld the joints, just use the clamps. Drive it for a few days, and if you don't like it, then remove the muffler and knock the baffle out.


MikeyB

 

Has anyone looked inside the Nelson 86131M or the Donaldson M090544 to see if there is a baffle in the 4" pipe?

 

According to a post on TDR the Donaldson has the cone shaped baffle in it.

How about the Nelson 86131M?

 

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!

 

Cool Big Bob.

MikeyB

 

Well, after reading here I no longer have confidence in Fleetpride's ability to properly supply the correct muff when asked for a Donaldson M090544 or a Nelson 86131. They've told me the donalson M090544 crosses to the Nelson 86131 (which is correct in my opinion) but they've also told me it crosses to the Nelson 86108 (really bad cross) and now BigBob gets an 86713M (better than the 86108 but still not correct).

So FleetPride gets a raspberry from me.


For review, here are the donaldson M090544 numbers:
1638 at 2" Hg
2006 at 3" Hg

Ok, can you guys at FleetPride read? I have the Nelson catalog and application guide in front of me and the numbers agree with what BigBob found: The Nelson 86713 numbers are:

1450 at 2" Hg
1750 at 3" Hg

That doesn't meet the Donaldson spec. And, according to the catalog, the 86108 numbers are:

1350 at 2" Hg
1600 at 3" Hg

Which is even worse. What you really want is the Nelson 86131, which specs out as:

1670 at 2" Hg
2000 at 3" Hg

Which is clearly equivalent to the Donaldson.

Now, Big Bob, to answer your question: you have a muff that allows 1750 CFM at 3" Hg backpressure instead of 2000 CFM. As a practical matter this probably will be a very small difference. The design point which this thread was exposing is this: A 5.9L turbocharged, aftercooled engine running WOT at 3000 rpm and 1200 degrees EGT delivers 1600 CFM: So pick a muffler that presents no more than 2" Hg backpressure at that flow rate. That design point is rather conservative -- I developed it after talking with donaldson -- they told me to take the engine operating CFM and target 2" Hg. I took the maximum possible CFM of 1600.

So BigBob, your 86713 is within 10% of the desired flow rate for 2" Hg backpressure. So I think you'll be fine -- its just that, had you had you known this earlier you might have held FleetPride's feet to the fire and compelled them to ship you what you asked for.

The only other things of interest I can add from looking at the Nelson catalog, is that the 86131 is widely used on Mack, Navistar, Detroit Diesel, Caterpillar, and Cummins engines up to 475 HP.

The 86713 has no engine application data in the catalog and is listed simply as a "EM" (economy muffler), and with a note that the outlet end of the muff is domed for vertical installation.

 

I'm confused.... cross references have always been a gamble anyway when going from one manufacture to another so why use a Donaldson part# to try and come up with a Nelson?

It's a better idea to use the Nelson catalog if you want a Nelson product.

 

Oh Wonderful! I installed the domed end as the inlet not the outlet! I thought with the dome, it would keep dirt and grime from collecting on the front of the muffler. I looked for directional arrows and any indication of which way it was suppose to be installed and found none.

Do you think I need to change the direction of the muffler?

 

Bingo. This came up because a someone here went to FleetPride for a Donaldson M090544 muff. The M090544 has from the beginning (of this inquiry) been the targeted product. Well, in this particular example, FleetPride complied and said they could supply the M090544 muff, and then the device arrived in a box that said "Nelson M4490" on the side. So then the search was on to find out what on earth FleetPride was suppling against the request for the Donaldson number and if "M4490" was a good muff. We discovered that M4490 is not a Nelson number, and is some FleetPride number that maps to something else. ok, not to panic. this kind of thing happens all the time in the industry. In all likliehood, FleetPride sourced a Nelson muffler, but can't publish the Nelson part number. Hence M4490.

My initial contact with Fleetpride was reasonable and I was told that M4490 was a good Fleetpride number and that they sourced a Nelson 86131 against it. So in response to what FleetPride told me at that time, I posted that Fleetpride M4490 = Nelson 86131 and gave the numbers. I looked up the Nelson numbers, according to what FleetPride had given me, and voila, everything looked according to Hoyle.

Now we learn that BigBob ordered an FleetPride M4490 thinking that he would get something equivalent to the Nelson 86131, or ultimately our original design point, the Donaldson M090544. Now he has, not an M4490, not an M090544, not even an 86131, but a Nelson M86713.

and so my confidence in FleetPride is gone now because they have demonstrated that they will supply most anything that some moron thinks is close to what the customer requested, and that all you can count on is that the muffer you get will have the same exterior dimmentions as what you requested.

So in the course of this whole happy experience we have discovered that either a Donaldson M090544 or a Nelson 86131 are the muffs of choice for this application. I remain convinced that these are good numbers and quality mufflers. What is the FleetPride M4490? now I'm convinced its a one-off, not reliably crossed (as I was told berfore) to what we were wanting originally, and that somebody at FleePride isn't playing with a full deck.

so you're right Matt400, the right approach would have been to seek out either the Nelson or the donaldson parts instead of the FleetPride numbers. Actually I reccommend not even using FleetPride unless they can supply a box with Nelson 86131 or donaldson M090544 printed on the side.

 

If you are after super quiet exhaust with decent flow, you might want to consider Donaldson's "Silent Partner" series. These muffs are 50% quieter during acceleration and engine braking than any other muffler on the market, including their own standard muffs, like the 51 incher you are focusing on.

Here's some info:
http://www.donaldson.com/en/exhaust/...ary/000369.pdf

http://www.donaldson.com/en/exhaust/...ary/000371.pdf

Just thought I would throw that out there since most of you indicate the noise factor is a big issue.

 

Well Doug, being that there was no directional instructions on the 86713M, do you think that it will flow either way efficiently? or am I going to have to change the direction of it?

 

good question! Just my guess, but I think it would depend on the orientation of that baffle in there. one direction might flow better than the other. If you decide to take it out, then it won't matter.

 

Thanks for those links AK RAM.
That was some interesting reading for sure. I see they mentioned that these are for vertical installation only and that a horizontal model is planned in the near future. This brings question why one cannot use a vertical muffler in a horizontal application? Well...I guess you can but what is it about a vertical vs a horizontal that they need to build different models.

I think the focus is on a straight through design that is the most quiet and thus the reason for a 51 incher that many are after. Lots of flow with the least amount of noise.

The Silent Partner sounds like a good one for use with a 5" system but I question a horizontal install when they say its only for vertical.