I got off topic in a couple other threads on this so am gonna start a new one..

My goal was to increase flow while keeping it quiet but didn't succeed. I used a muffler I don't think anyone has tried yet and felt it would be good to not only share my findings but ask opinions also on a second change.

This is what I did:
4" down pipe into 5" pipe then into the new Donaldson "Silent Partner" 51" muffler that is 5" inlet/outlet.
At 3" of water it measures 2652 airflow cfm and at 1" it measures 1630 cfm.

With a 5" inlet and outlet I used a 5" tail pipe so increased flow I am sure I managed.
Light unloaded cruise is tolerable on the flat is ok with a deeper note, WOT runs are ok too in the upper rpm's but hills or any towing fills the cab with a deep horrible drone at the 1600-1900 rpm range that has to go!

So now I gotta change the dang thing all over and am looking at these options all of which will keep the 4" down pipe:

• Rips Diamond Eye Louvered straight through muffler
• 51" Donaldson or Nelson straight through design 4" in/out
• Banks 4" in/out

Which one do you all think would be more quiet while towing?

Any thoughts on those or suggestions for something else?
I would go back to a 4" tail pipe. I hear the Banks is too loud for towing and the first two are ok for towing but surely don't want to do this again!

My truck is a short bed and that may have something to do with the drone as my current 51"er extends well up under the cab where as the OE muffler was at the end of the cab.

 

The Diamond Eye was my first muffler. Terrible. Airish ricer sound.

The 51" straight through 4" without baffles seems to be the ticket. I'm sure someone here that has one will chime in with a part number. Donaldson or Nelson. Folks are happy with both.

 

AK RAM,
Since you have had both and besides the "tone" you didn't like with the Diamond Eye...which one produced more noise under load 1600-1900 rpm's with windows up?

 

Matt400,

I am extremely pleased with the Nelson 86131M. It is a 51" - 4" in and out, with no baffle.

 

My Donaldson is the 34" model. The Diamond Eye was a good bit louder at cruise, even with the windows rolled up, but no drone per say, just loud. Never did pull with it. It only lasted about 3 days and went bye bye. Now a friend of mine has a Diamond Eye muffler on an 03 HO with the stock 3.5" piping and it doesn't sound too bad. My piping is 4" all the way. Maybe that made a difference or maybe there are two different models floating around out there. Might be better to steer away from this one (too many unknowns) unless you are feeling lucky. Besides, it is more expensive than the standard straight through Donaldson and Nelsons.

It is usually resistance or very un-smooth air flow in the muffler that causes vibes that equate to drone. Is your current muffler welded on or clamped? Depending on how much effort you are willing to put into it, the funky baffles in most of the Donaldson and Nelson mufflers (the ones that have them) are just lightly tacked into place. If you were to take that muffler off, you could probably knock those baffles out. Then again, they are not a big ticket item either. It would probably be easier to just buy a different one.

I would definitely recommend the 51". My 34" is getting louder as I bomb. I will eventually have to do something to quiet it down. Love the tone though. Sounds awesome.

There are quite a few threads where we discussed flow ratings, sound characteristics, etc., of the different Donaldson and Nelson mufflers. Have you done a search in the 3rd Gen Performance forum on keyword "Donaldson" or "Nelson"? A lot of good reading for you there.

Good luck.

 

Alot of people pleased with the 51" 4/4 mufflers are running the stock 3.5" or 4" downpipe. Your 5 inch plumbing might make things alittle bit more noisier even with the 4/4 muffler.

I'm shopping around currently for the 51" 4/4 to use with a Banks or ? full 4" downpipe. I hope to have it installed by the end of next weekend. Then it's time to commit on that feuling box or injectors.....

 

It never lasts long, does it?

 

I recently installed the diamond eye dual exhaust set up on my 03 Dodge cummins and a dual set up on my friends 03 d-max and in both cases sound is unbeleiveably QUIET, outside truck it sounds nice, inside is quiet not towing and when towing you can hear it but NO DRONE just sounds clean
I was really surprised about the outcome, I went into this thinking I would be adding a donaldson 51" or a second muffler to control noise but to my surprise it wasw great, heck my wife even likes it, and that dont happen often...

 

Big Brother Dodge is watching!!! They probably busted at least one person over at the TDR when they ran an EZ and then had problems with their tranny. I might speculate what I'll do to my truck in public, but I'll never confirm it.

Yeah, there's been that controversy on being your own warranty station, but I don't want Dodge just putting my warranty on restriction from what they read here. I feel that I would be responsible if I broke something and take care of it out of my own pocket, like I've done in the past.

>AK RAM wrote:
>It never lasts long, does it?

 

I have the same one and also love it, no complaints from the wife either.

 

Yes, maybe but what I have is a 4" down pipe that is pretty long and only has a 12" section of 5" pipe before the muffler then a 5" tail pipe.

Thinking the the noise was echoing in the big tail pipe I pulled it off just for fun and the drone was several times worse with only 12" of 5" inlet remaining.

The thing about the 51" Donaldson Silent Partner is when studying the design its hard to believe it could present a problem.
At 51" there is a good two feet of it right under the cab on a short bed and I am beginning to wonder if that is not a good spot for a sound absorbing devise that could transmit sound waves to the floor board.

What ever I do I will make it all 4" but hesitate on another 51" cuz it looks as though the ones that like it have long beds which put it much farther back. There could be some reasoning why the OE muffler is short to keep it away from the cab.

 

Its clamped in 3 spots and welded in the others. Good thought on the baffles as those could be vibrating and even transmitting sound waves to the muffler housing.
Yep thats where I originally started but it was difficult as so many who change their systems want more noise and it was the quiet 3rd gen that was a major selling point for me.

 

Like Matt I would like to hear from a short bed owner and how the donaldson sounds.

 

4" Magnaflow. A little louder at idle. It gets louder as you get up in the rpms but not too bad....

 

I like the Banks 4" turbo back system I just installed. I eliminated the cat. and the sound is wonderful, lower throaty tones without the dreaded droan. With windows up not much of a interior difference. Fit and finish of the system was outstanding.