Which performance muffler on the market is quietest. I've had my 4 inch system on my truck for about 7 months, but I think it's time for a quieter muffler. I feel bad for my neighbors when I fire up my truck at 4:45AM. The muffler I have now is a off brand. I read a thread about the Donaldson Muffler. Any suggestion????


Thanks

 

There is a 51" Donaldson available that I would think would be fairly quiet. I'm looking for something louder than stock myself.....and I'm considering the 34" Donaldson (among other things).

 

I have the Nelson 86131M. It's a straight though 51" muffler with no baffle. It sound real good, not too loud, but loud enough for you to hear in under throttle and while cruising, it is nice and quiet like the stock muffler. I put a 6" Stinger on the end of the tail pipe and it gave it a real deep tone! Much better than the stock tailpipe.

 

Where did you get the Nelson Muffler and how much did it run you? It seems the longer the mufffler the quieter. My current one is '30 long. I guess I will need to cut some pipe off. Thanks

 

I don't like loud mufflers at all. My 34" Donaldson sounds real good to me, but if it were ANY louder, we would have issues. I only have two beefs with mine: (1) 1500rpm drone. Not present just below or just above 1500, got to be spot on. Local muffler shop said it is caused by vibration and if I weld all the seams in the piping (mine is pieced together with scrap) and add a few more hangars for rigid support, that will stop the drone. If that is the case and it is my setup that is causing it, then no one else should experience drone with this muffler. (2) Sounds absolutely great at idle, cruise, and light acceleration, but when you let'r rip, EVERYONE hears it. I guess that could be a good thing though.

The 51-inchers may not flow quit as good, but if your goal is quiet, that is the way I'd go. If your not too concerned about feeling the need to light'em up at 4am in front of your neighbor's house, then the 34" will do you proud.

 

I have the 51" Donaldson and am very happy with it. With the windows up, I hear virtually no exhaust noise. I can hear the turbo spooling up better than the stock, but I also have an AFE on. Put the window down and it sounds low and sweet. If I bounce it off a guardrail or a ricer is beside me advancing to the rear, it is noticealble but not objectionable at all. Sounds like a big rig at a little distance.

 

Where's the good (cheap) place to buy?

 

I went with the 34 inch Donaldson. I talked to Bob at Air Flow Inc and he said they sell way more 34' than the 51's. Also, he advised the 51 inch is a lot more restrictive than the 34 inch. At $73.00 its not that expensive...I guess we will see......

 

I'm considering putting in a straight pipe for a while. I'm sure it will be loud and I want quiet. I want to see what full flow is like. That will tell me if the shorter louder one will be worth the noise. Sorry to jump on someone elses thread. Seems like many of us are going through the same hoops on these things.

 

The Magnaflow XL muffler, IMO, is quiet.

 

The folks at Air Flow Inc. are just plain o'l good people. I have purchased a bunch of misc. stuff from them for my experimentations and have never gotten grief when I wanted to return stuff I didn't use. However, if you use the dealer lookup function on Donaldson's web site (Nelson's as well) and find a dealer in your area, you will save some cash. The Donaldson web site pointed me to a local Freightliner distributor in town here and sure enough, they ordered the muffler for me from Donaldson for suggested retail, which is $50.00, took three days and no shipping charges. Air Flow Inc. also has the BHAF I'm looking at, but they want about $150 for it. Donaldson makes it, so I can get it locally from the same Freightliner distributor for suggested retail, which is $101.00. I'm rambling again....The point here is, use Air Flow Inc. for the hard to find parts, because they have all of them, but their prices are a little inflated. You will save money, potentially a good bit, if you can get it locally.

 

Just got back from putting on the straight pipe. Sounds pretty good. Not too loud but that's with nothing behind me. I might be pulling a boat down to San Diego and back Monday or Tuesday. That will be a good test. It is considerably louder when on the throttle. I'm heading down to SD tonight but I'm not towing anything. Right now, it seems to cover some of the noise coming from the engine compartment.

 

I got the 51" Nelson 86131M at Cummins Northwest for $63.00 plus tax.

 

I saw a link to a website showing the 51" muffler flowed very well, at least a heckuva lot better than stock. It was in a post somewhere. If a long muffler still has a full 4" opening all the way thru the middle I don't see why it couldn't flow well

I rode in Big Bob's truck last weekend and even with his box cranked and the pedal to the floor it wasn't that loud in the cab.

Vaughn

 

I added the Magnaflow 20 inch to my 4 inch dual system. It got rid of the 70-80 mph drone and is straight through with no restrictions.