Muffler installation with db comparison

[TexAndy]

The idea of an audio recording was mentioned earlier today. I used a Canon digital camera in the movie mode to make a brief recording. It was shot with the passenger window closed and the engine at about 800 rpm. The audio meter is recording the volume level with the Walker RV muffler installed.

The Walker muffler fit within the framework of the mirror bracket. I'm hoping to fab up a more suitable bracket for anchoring the muffler. For now, the 7.25" diameter u-bolt seems to be stable enough.

greg

Wow, that's great! Thanks!

 

[number9]

I've got the Donaldson muffler on my truck and have been really happy with it. MUCH quieter than it used to be.

....

 

[dozer1]

Ordered the Donaldson today. Should be here tomorrow or the next day. When I get the install done I will try and get a pic up on this thread as well.

 

[chgofiveo]

Hey MO MV Man,
Great install and great thread... get your heat shield on and camo it up and you will never see the muffler . Thanks for all the research

GREAT JOB !!

 

[dozer1]

As promised, here is my install of this muffler. I am sure its not alot different then MO MV mans and chigofiveos install. I did find it nessesary to do a mod to the lower mirror bracket as seen in the pic. Just a bit more bend where it is bent anyway, then an extension at the end. I used the stock support bracket, but did elongate the holes a little bit to move it as far in as i could. It just seemed to need that little bit more clearance. Now as a possibility for someones future install, I know Donaldson has 1 longer muffler with 3.5" ID ends. I dont have the part # but it was about 30 bucks more. I bet it would just perform all that much better. Lower DB, less restriction (if there is any) OK, I found both on the Donaldson website here is the link for the M070028 https://dynamic.donaldson.com/webc/WebStore/search/item_detail.html?section=10210&item=23070
Here is the link for the M070050 https://dynamic.donaldson.com/webc/WebStore/search/item_detail.html?section=10210&item=23046

You can see all the specs, I would try a M070050 somebody?
My Edit: The taller muffler would require doing something different to that upper support bracket. Not really sure if any gains are worth changing it. You decide.

 

[rlwm211]

I think that the largest contributor to the noise level in the cab of a deuce is the distance from the outlet to the place where you are measuring the sound level. I used the "bullet" muffler approach and did not trim my upper stack at all when I put that together. This raised the outlet at least 20 inches. Another item to note is that most of the stock deuces have their outlet of the stack turned slightly to the rear thereby increasing the amount of noise in the cab. I turned mine so it is straight to the side.

No matter which path you take, quieting the deuce is good for your hearing and it does make us better neighbors in the community which is good for all of us.

Quite honestly, if the neighbors knew a stock deuce has NO MUFFLER AT ALL they would be up in arms and demanding we not have a deuce in the neighborhood.

Great work on the installation and the documentation of the changes in the sound levels. The same goes to all who have added to the discussion.

This adds nicely to the information database that is STEEL SOLDIERS...

RL

 

[Tow4]

I put the Walker muffler on my Deuce about a month ago. Now I can hear the transmission, transfercase, axles singing and all the other stuff rattling. I still use ear plugs going down the road. I plan on putting a rubber mat on the floor for insulation and sound proofing.

My wife was happy to see the muffler didn't cut down on the smoke.

 

[monstermog]

Since the muffler is strapped to the body...If you could isolate the strap, and put up some firewall and floorboard sound deadening, possibly even isolate the cab itself from the frame with rubber isolation dampners or air/shocks you could take out alot of noise. I used to ride along with my frind who had a Deuce and with the short stack...it was very noisy...ear plugs a must! Since I had to do some repair to the Muffler side of the truck...That truck was prime for alot of simple noise cancellation/noise interferance/dampning products. I'm sure a little would go long way. As much as a stack out front looks great...why not take it directly back to the middle of the truck and down....

 

[monstermog]

http://www.maximsilencers.com/standard-chamber-exhaust-silencers-M62.html

Theres several companies that make silencers/mufflers for hospital specs. Level 100, 200, 300 and 400(Hopsital specs).

? I don't think a muffler like above would be necessary as getting rid of one area of noise would then allow you to hear other areas of noise...ie...wind noise, engine noise, chassis noise, tire noise ect. What is the optimum acceptable noise level without hearing protection?

 

[Katahdin]

Since this thread was revived here's my Donaldson install while I was working on a 24087 makeover earlier this fall. Note, I have elephant ear mirrors which did not require any modification. After some careful J pipe trimming I was able to use the original clamp on the top and just add one on the bottom.

I plan to add the heat shield at later date after I get some welding skills under my belt. It's great to not have to wear ear protection anymore!

 

[Autocar]

In my former life, I did the noise reduction engineering for Fabco trucks. What I found was that the simplest and most important method of noise reduction was to fill all holes in any structure between the listener and the noise source. On a truck, this would be the holes in the floor for the shifter and any floor levers(i.e. put a "boot" around the opening) and sealing any holes in the firewall where things go thru the firewall(throttle linkage, cables, hoses). This seems minor, but you get huge decreases(whole numbers of dB reduction-remember, each 3 dB(A) is a reduction of 1/2 the sound loudness) in sound level for very simple changes.
The second thing is to locate the source of the loudest sound and focus on killing that sound by isolating or enclosing or adding sound deadening. Essentially, the human ear only hears the loudest sound and the other sounds are not heard. If other sounds are more than 10dB(A) quieter than the loudest sound, they completely disappear. They essentially have to be within 3dB(A) of the loudest sound in order to add any noise to the percieved sound level. This is why the above comments about hearing tire or gear noise after adding a muffler. The exhaust level dropped low enough that other noise sources can now be perceived by the ear.

If you want to quiet the truck, you work on each noise source one at a time. Move the sound meter around until you find the loudest area or component and figure out how to kill that sound. After you have killed it, some other noise will now appear and that is the new loudest sound. Sometimes, previous loudest sounds will reappear. For instance, if you added a muffler and now you hear gear noise. If you quiet the gear noise with isolators or floor mats or sound deadening, the exhaust may once again become the loudest noise. Until you make the exhaust quieter again, anything else you do will be futile. The exhaust didn't get any louder, the total overall noise level dropped and the exhaust is quieter than before but it is still louder than anything else.

I have an M818 that I am going to be quieting as a future project and I will be posting each change and its improvement .

 

[shenkmen]

Since this thread was revived here's my Donaldson install while I was working on a 24087 makeover earlier this fall. Note, I have elephant ear mirrors which did not require any modification. After some careful J pipe trimming I was able to use the original clamp on the top and just add one on the bottom.!

I added a Donaldson M070028 just like Katahdin posted above. It fits between the mirror assembly and the fender. I guess it decreased the sound by at least 50%. Perfect for me.

Attached is the official Donaldson Muffler spec sheet. Open it and search for the M070028.

 

[shenkmen]

Cross referencing to post - http://www.steelsoldiers.com/deuce-...g/70365-source-donaldson-m070028-muffler.html

 

[cranetruck]

Good thread, missed it completely the first time around. Thanks Gerhart for the reference (sorry I couldn't make it to the rally).

 

[jstier]

I work for a donaldson Distrubitor.
I only use Donaldson Products, Not only since i get them at cost, but because of quality of product.
I have personally seen how much better filters they are then other brands. We put some trial filters @ a steel Mill. Same rating as the other brand. Thier testing came back a couple levels cleaner than the other brand.

 

[bones1]

Autocar, great information. I bought a M353570 muffler (ordered a m070028 and I got a M353570) from Fleetpride. I suppose it is the old # and is dimensionally identical. Installed it last night with a new J pipe.I will get a larger piece of expanded metal and fab a new shield as soon as I figure out which size expanded metal to buy.I see a couple different mesh sizes to choose from.

MetalsDepot® - Expanded Metal Steel Sheet

 

[3dAngus]

To those who might look at that and say, "but that's only 11db......only 4 db....".
db readings are interesting.
A 10db reduction, for example, is HALF the previous noise level!
A 5db reduction is quantified as "a clearly noticable change".

Another good thread with measureable metrics, thanks. One note:

3 db is half, or 2X's if it is a 3db increase.
10db is ten times.

The human ear has a tendency to make compensation so you won't really notice a 10X decrease in noise, but you will notice a significant decrease. A noise meter will measure it more accurately, where you can obtain a weighted average value that can be used for hearing warnings spread out over time, whether instantaneous, or over a 8 hour averaging period.

I hope we see more measuring on these installations, taken from the exact same position or location in the deuce cab. A digital sound meter can be purchased from Sears or Kmart for about $40. Thanks for the data. Looks like a muffler install is a great way to go. I would love to see some numbers on sound absortion material, or rubber matting on the floorboard, firewall as well.
I'm going to be installing some rubber matting from Tractor supply for this purpose, and when done, will post some numbers. Thanks!

 

[andytk5]

I have the large walker RV muffler and just purchased an exhaust diverter that will let me select the open stack or the muffler which I am routing out the back through the muffler.

Does anyone have any readings of muffled exhaust out the back of the truck? I would think this would cut down noise even more like somebody said, the distance from the outlet. I like this since I can keep the open stack, yet tone down the noise.

 

[gringeltaube]

.........(sorry I couldn't make it to the rally).

No excuses for not spending at least two days there... and better be prepared...; next year someone WILL go, kidnap you...!

G.

 

[Heath_h49008]

Bumping this up because barring unforeseen problems, I will be doing this mod tomorrow. Pictures to follow as well as an attempt at a before and after video with audio.

Edit: No joy. I need to grab an adapter to put the top back on. Maybe sunday.