I have searched the forums, but havn't found what I'm looking for.

I went on my first trip pulling my 8000lb travel trailer after installing a new home made exhaust system and it was WAY too loud in the cab.

My current set up is no cat, a 24" body lenght Magnaflow muffler, and a side pipe. (I'm not trying to break the rules by talking about not having a cat, but I thought it's important to the discussion to say it).

So, here's the questions: how can I modify the exhaust to make it a lot quieter (as quiet as stock if possible), but still have free flow characteristics? I have read that a 51 inch Nelson or Donaldson muffler makes things quiet, so is this the best solution? Any suggestions for making this truck quieter while towing? I'm open to almost any option at this point!

If a Donaldson/Nelson muffler is the best choice, where does one get one? (I couldn't find that searching the forums either.)

Thanks a bunch for any help. I'm really in a world of hurt trying to keep my head from exploding when towing!

 

to get a little quieter you can throw that cat back on there. but my opinion if your looking for the same thing im looking for, which is not loud but just a little more throatier and deeper tone than stock is go with the 51" nelson or donaldson mufflers. these can be ordered from cummins or just go to your local freightliner dealer and they can order them for you... hope this helps

 

HorseHauler, do you have the part #'s for the Donaldson & Neslon 51" mufflers ?

 

the nelson part number is 86131
the mufflers are pretty much the same so if u can find a freightliner dealer i know they carry the nelson 51" muffler. ill try to find the part number for the donaldson

 

found it 51" Donaldson Part number M090544

 

ditch the side exit and get a tailpipe on there!

 

I have a 51" donaldson and a 30" magnaflow and I think the magnaflow is quieter and has a deeper tone.

 

I agree with Forrest on putting the tailpipe back on. You can also add an Aeroturbine right off the downpipe and those are supposed to help alot, especially to reduce drone....

 

I agree with the above, put a tailpipe on it and try it,I had a side pipe on before the stack and the drone was unbearable, also you want to be sure to use some good quality rubber insulators to hang it all on or the vibration will be real bad. I think some times the vibration is confused with exhaust drone because of a solid mount?..........

 

Ya, I was kinda thinking the side pipe may be part of the noise problem, but I liked having a more unusual exhaust arangement, BUT I think I'll like not having to wear ear plugs better!

I used a Summit universal eshaust hanger, which is mostly metal and has a little rubber section in it. Is this one alright?

So, it looks like the best answer is to try a 51" Nelson or Donaldson. My budget is a little tight so I think I'll just add the 51" now, and then try an Aeroturbine if it's still too loud.

Thanks again for the help!

 

Put your cat back on....it doesn't affect performance.....many dispute this, but show me numbers to prove it. Afterall, if you put it back on, you won't have to deal with invalid warranty issues.....I guarantee they will come up if the dealer spots that bad boy missing.

Also, the aeroturbine will definately help.

I also left my rear tailpipe in the stock location but added a RIPS SS tip which will give it a different tune as well.......

I'm happy

 

Besides warranty and law issues, putting the cat back on will make it quieter, right?

That's a good idea. I think I will put the cat back on. Is there much of a difference in EGTs with and without it?

 

Just been looking around and found this. Do any of you have a thought on putting this resonator in the line somewhere? It says it's straight through so good flow but not much silencing maybe?

 

I see you have a SWB. If you choose to go with the 51" muffler, and put the cat back on, I dont think you will have enough room for the resonator. I wouldnt worry about it though, I havent heard anybody complain about drone with these mufflers. I would check the room you have available anyway.

 

I did not know you could order a muffler from a freightliner dealer, THANKS for the info since I work for the freightliner tmp I will look into it monday.