4" resonators/mufflers to quieten down exhaust

[Hutch24v]

Anyone have first hand experience and can recommend a good 4" exhaust muffler/resonator for sound deadening?  I need to tone down my 4" exhaust sound some and at the same time not restrict flow. I've seen a few models - Aeroturbine, MBRP Quiet Tone Muffler Resonator. I've got an existing muffler which the PO installed but can't tell the brand. In any event its a bit too loud and showing some signs of rust. Any suggestions?

[Mopar1973Man]

I'm running 4" diamond eye exhaust without a muffler and it pretty quiet most don't notice. The only time it loud is when the loud pedal is pressed firmly then Beast will talk just as loud. I did have the muffler on the truck and it was pretty darn quiet in the cab but still had a bit of a voice with a muffler. 

 

Personally the 3" stock exhaust was quieter with a muffler than 4" exhaust with a muffler. 

 

 

Edited July 17, 2022 by Mopar1973Man

[Hutch24v]

Yeah but I do  need to press the loud pedal often. 😊

[jlwelding]

16" mbrp I got free from my son in law is working good for me on 4". I also put a 45 miter cut on the end to disperse the pop. A little trick we did back in the day on our shovelhead to keep Johnny law off our azz.

Edited July 18, 2022 by jlwelding

[LorenS]

I run the muffler that came with my 4" Diamond Eye system. It's a straight-through and knocked down the noise really well. The front end of my truck is far louder than the back end.

 

Mine exits in stock fashion, behind rear tire.

[Hutch24v]

Yeah not a lot you can do to the front end sound of a 2nd Gen. But I did add a noise suppressing thermal blanket to the valve cover which helps. cuts ~10-15 db’s. 

[LorenS]

7 hours ago, Hutch24v said:

noise suppressing thermal blanket to the valve cover

Fancy!  Is that from ATP?
https://atpwrap.com/2020/08/13/advanced-thermal-products-inc-is-a-manufacturer-of-high-temperature-insulation-systems-for-the-diesel-power-generation-aerospace-and-race-industries/

Edited July 21, 2022 by LorenS

[Tractorman]

7 hours ago, Hutch24v said:

Yeah not a lot you can do to the front end sound of a 2nd Gen. But I did add a noise suppressing thermal blanket to the valve cover which helps. cuts ~10-15 db’s. 

 

That thermal blanket looks familiar.  Did you get it from Advanced Thermal Products? 

 

They installed a 5-pieces set on my engine.  Helps with engine noise abatement, but really keeps the engine bay and passenger side floor much cooler.  The blankets have been installed for almost 7 years and over 120,000 miles now.  There is no sign of degradation of the material or the components the material covers.  The initial cost was high, but for me, it has been well worth the expense.

 

- John

 

 

 

[Hutch24v]

Yup, ATP. Part of the ”quiet dodge” kit. I have the oil pan cover too like yours tractorman. You went all out with it.  I did have the manifold/turbo cover but since took it off when I made some turbo changes.The most effective pieces on noise abatement are the valve and oil pan covers. The owner of ATP was a great guy when I talked to him. Pricey product but it works.

[LorenS]

I see the price for the valve cover blanket is $300.  That's a lot of money, but I drove my truck 3 days this week (have been commuting in my VW Passat TDI) and my ears are already feeling 'weird' again.  My A/C has a leak so I have to drive windows-down.  But even windows up in the winter my ears didn't like the truck.

If my truck didn't leak so much oil I'd get the oil pan cover, too.  "One of these days" I'll get all the leaks fixed; I have the crank seal ready to go in, figured I'd do that when I put in the new A/C condenser, which would also be a good time to install a new cam.... 

[Threadzy]

I was just checking out their website. They didn’t list any prices. I’m wondering if you could put  Dynomat or some other type of other sound deadener around the oil pan and valve cover? I put some on the cab behind the back seat. That made a difference. I had  header wrap around my exhaust  pipe past the transmission. Had to take it off when I put my exhaust break on. Had to weld a flange on to bolt up to the 4” down pipe. Need to put it back on. Especially in this heat. 

[LorenS]

2 hours ago, Threadzy said:

They didn’t list any prices.

I found this on Cummins Forum after doing a Duck Duck Go search.  It's from this spring.

Regarding Dynomat, I just question whether its adhesive would work with the temperatures seen on an oil pan, maybe it'd work on the valve cover.  But Dynomat doesn't offer much mass; it's great for killing high pitched harmonics on a sheet of steel, but not sure it'd do much on something that's already stiff like a cast valve cover. The valve covers already 'thunk' more than 'tink' when tapped.

 

Edited July 21, 2022 by LorenS

[Tractorman]

In late October of 2015, my wife and I were finishing an East Coast Fall Colors Trip with our travel trailer in tow.  We traveled though some southern states on the return portion of the trip.  While we were  passing through Arizona, I told my wife that I would like to stop at ATP in Irvine, CA to check out the engine thermal blanket kit available for our slightly noisy Cummins 2nd generation 24 valve engine.

 

We arrived at ATP about mid-morning and I met the owner Tim Thompson and, as @Hutch24vstated - he is a great guy.  He gave us a tour of his shop and introduced some of his  employees.  The shop is hard to describe.  Basically, it is filled with employees operating commercial sewing machines (like long arm quilting machines, except heavier duty).   He said he got the thermal blanket part of the business going because of the need for it in the car racing circuit.  Now he does custom fitting on engine exhaust systems on the Coast Guard fleet of boats and ships.  He also insulates engine compartments on high end motor homes - such as ones that celebrities drive to his shop and visit with him while his crew install the material.  He said that Ernest Borgnine would stop in with a new motorhome every couple of years to have the engine compartment insulated and while he waited, he would visit with the crew for a couple of hours and telling jokes.  The crew loved him.

 

Anyway, Tim offered to make and install the whole kit (except for under hood) for $1,000 while we waited.  We agreed.  When the job was complete, we test drove the truck.  We were only able to attain about 30 mph in the neighborhood.  We left the windows down while we drove around, it was definitely quieter.  I was trying to not be overly optimistic about the sound difference, after all, Tim told me the product is primarily used to minimize heat transfer.  When we returned to ATP, TIm asked how we liked it.  I told him that we didn't have the opportunity to do try it on the freeway, but it is a bit quieter in town.  Here's the part that impressed me.  He said it will be noticeably quieter on the freeway, but if I have doubts or I am not satisfied with the product, he would happily have his crew remove it and refund the money.  He said he was serious about that statement and that there would be no hard feelings.  My wife said, "NO!  We are keeping it!"  And that was that.

 

On our trip back to Oregon, it was definitely quieter in the cab and as a bonus, my wife said the floor stays cool now when going up those long hills. 

 

One of the benefits so far has been the durability of the product.  It is not supposed to degrade, deform, or lose its effectiveness for up to well over 2,000° F.  So far, it has done its job well.

 

- John

 

  

 

[Hutch24v]

Great story John. Good to see your blankets are holding up 7 years later.  I hope these kinds of quality small businesses like ATP live on.