Inside Pics of 51" Donaldson Muffler

[JohnnyH]

Some people asked me to post pictures of the inside of my Donaldson Muffler. Here they are.

 

[JohnnyH]

The top one is the Inlet and the bottom is the outlet.

 

[Cigar John]

Now take a long bar and a big hammer and open up the "crimp" a little. :-laf

 

[JohnnyH]

Too late. It is on the truck the way you see it. I like the way it sounds as is. I know some people have opened it up though.

 

[ToolManTimTaylor]

Hey Jon,



Can you give me an idea as to how much of a difference in EGT Rise you are seeing? Anything that restrictive has just got to raise the exhaust temps no?

 

[Bugracing]

Johnny;

Thank you for the pictures. How did the sound and performance change versus the stock muffler?

 

[JohnnyH]

Hey Jon,



Can you give me an idea as to how much of a difference in EGT Rise you are seeing? Anything that restrictive has just got to raise the exhaust temps no?

If anything temps have dropped slightly. Not much, but a little. That muffler flows 2000 CFM at 3". 4 times as much as the stock muffler. The flow specs are almost identical to the Nelson 51", which dosent have that crimp, so I dont think it impedes flow too much.

 

[JohnnyH]

Johnny;

Thank you for the pictures. How did the sound and performance change versus the stock muffler?

As far as sound is concerned, it has a deeper tone, slightly louder than stock, and no drone at all. It is not so loud as to be irritating. Performance wise, it is hard to tell. My truck is stock, so the stock system was probably sufficient, but I was after the sound. I have pictures in my gallery of the install.

 

[Hokey]

muffler

Thanks- great information and pictures, nice to have real numbers. I wonder how much that cat is designed to flow or how much backpressure it creates

have you seen any numbers on that? Thanks again

 

[JohnnyH]

No, I dont know what the Cat flows, but I have emmision inspections here in NY, so I left it alone. I have heard that removing it gives negligable benefits, but I dont have any information to back that. I did a full write up on that muffler in the 3rd gen forums a recently, if you want to read more on it.

 

[DBrickel]

Yikes, Thats the muffler I have on mine. I sure didn't know it was that restrictive. I think I'll call Rip and order his Diamond eye. It sould help my EGts

 

[Forrest Nearing]

guys, there are tons of 51" mufflers... that's the standard length muffler in the big truck world... rule of thumb: if you can't drop a grapefruit straight through it, you don't want it on your truck...

 

[JohnnyH]

guys, there are tons of 51" mufflers... that's the standard length muffler in the big truck world... rule of thumb: if you can't drop a grapefruit straight through it, you don't want it on your truck...

Why. Tell me how it is so restrictive when the flow numbers are the same as the rest. It may change the sound, but if it flows 2000 CFM at 3" and the Nelson flows 2000 CFM at 3", you tell me how it is so restrictive.

 

[Hokey]

grapefruit??? How many (GPS) How many grapefruits/seconds will your exhaust handle? I would rather hear a gas flow volume at a pressure. I'm not sure how to do the math in gps. Exhaust gas temps. are always interesting as well as sound clips. but I think the most important factor is owner satisfaction.

Thanks again Johnny for the pictures, looked at your install and like the looks of it as well as your comments.

 

[Forrest Nearing]

Why. Tell me how it is so restrictive when the flow numbers are the same as the rest. It may change the sound, but if it flows 2000 CFM at 3" and the Nelson flows 2000 CFM at 3", you tell me how it is so restrictive.

your eyes ok?



are you telling me you can't look at that and tell it's more restrictive than a straight through?



which part number did you get, there are more than one 4" 51" Donaldson.

 

[Forrest Nearing]

they all have that baffle in them, but if you look at the flow numbers on the 40" without the baffle, it flows 3119cfm. slightly better than 2000, no?

 

[JohnnyH]

If you do a search on all the 51" mufflers used by TDR or DTR members, it is M090544. That is the one I got, and the one of the picture above. It is stamped on the muffler. I know the 51" Nelson does not have that crimp, but it actually flows 6 CFM less than the donaldson. 2000 CFM vs 2006 CFM. The same for all intensive purposes. If I wanted straight through, I would have just straight piped it. I'm happy with the sound of this one.

 

[JohnnyH]

Yes, the 40" flows more, but I dont was after the more mellow tone of the longer muffler. I remember reading somewhere that the 5. 9 Cummins at 3200 RPM pushes something like 1600 CFM. I forget where I read that, but it came up during one of my searches. Anything equal to or over that should be more than enough flow for our engines.

 

[SRadke]

I remember reading somewhere that the 5. 9 Cummins at 3200 RPM pushes something like 1600 CFM.

In stock form I can believe that. There are a few members of this board who's trucks flow just a wee bit more than that though



-Scott

 

[Hokey]

This is the first time i've seen CFM numbers, Interesting, are all these at the same pressure? 3"? 3"'s? Hg,H20?? Forest what is the part number of that 40"

is that a donaldson? Too many questions, going to the search.

thanks