Exhaust mufflers under making.

[zlimmy 78]

As i dont find the orginal, i decided to reproduce as close as possible to orginal. 

But i'm thinking of maybe add some silencer fibers on the exit part of baffler inside. I'll see it as a big + to get it as silence as possible without making more heat etc. 

 

Anyone with suggestions? 

 

[Tractorhead 9,122]

Most Bafflers work like frequency Filters.

 

the rotation speed is similar to frequency, but because it can raising or drop,

ther will be just few bandwith filtered.

in case of raisin* or drop rpm, there will be different solutions.

 

If you wanna filter (silence) a longer bandwith (several rpm speeds)

i would try a Bypass (Bandpass) baffler with different diameters in drilling your sieve.

 

Here a baffler i make myself several years ago, that work not bad in silencing.

i just give you the Values i used, no Warranty if this would work for your diameter

i used a 40mm Steelpipe as exhaustpipe

 

edit:

forgotten to given:

bafflerpipe itself was calculated dia * 3 /1.25

you have to add to this length the thickness of your separate rings.

that they ain‘t changing the used length.

2 additionally rings where welded later as endcaps.

:/edit 

 

Exhaust pipe(internal into baffler) is base.

surroundpipe (baffler self)  is Base * 4

Mark your baffler internal in three sections. Produce rings to seperate the chambers later.

the Rings should fit closely between exhaust pipe and surroundpipe.

 

Drill in direction from engine to end  

firstly section 1/4 of pipe diameter, the pipe similar to your Pics.

second section 1/6of pipe diameter.

last section 1/3 of pipe diameter.

each section the internal chamber will be build with a welded ring on the Pipe between the sections later

between chambers no filterwool inserted to dont disturb the flow of gas.

between the three chambers the will be expanding drills on the rings.

from first chamber to  pipediameter / 1.8

from second to third chamber pipediameter / 2.2

they must be mounted 180 deg opposite to inletdrills, to get the delay.

 

How it works?

adequate to your Stereo speakers at home, this work like Bass Reflex tubes, just opposite.

it was a reflection silencer.

 

in first chamber it keeps first time a lot of Gas in because the bigger drills.

in second chamber they will be pressured back, because the 1.8 bypass,

while the first pressure was released, the most gas passed the bypass and will be changed its wave to 180 degrees.

so it will smoothened the Soundpressure while a timedelay occurs.

next step was another damping stage.

The inlet and outlet pipe of the baffler , what they should be longer than the baffler pipe itself is dia * 2.5.

 

 

With this calculations i build my Baffler, normally it should reduce significant soundpressure.

Let‘s have a try. 

 

 

 

 

If you wanna try good luck.

Edited August 15, 2019 by Tractorhead
Corrected formula

[zlimmy 78]

I'll ended up with a copy on the orginal Nelson muffler internalwise. There was 24 holes in first chamber and 20 in second chamber. But these was 1/2 mm wider each. 

 

Bottom outlet has 18 holes with a 6mm diameter. 

 

I do miss tools for making a exact lookalike on the outside. But I'm satisfied so far. Only a little grinding left to do. 

 

I'm aware of a trick using stainless washing spong for pot cleaning inside muffler. Not sure of the effect, but i probably wait with the bottom plug, and see if can test it out a little in last baffle chamber. 

[zlimmy 78]

Here is the finished result. 

[Joker72 64]

How much would you charge to make 2 more?

[andrewLL 17]

Looks good, but does it work well?  Is it nice and quiet?

Andrew

[zlimmy 78]

As i don't have reference, i'm not 100% sure. But i did make it almost exact as the rusty orginal i had. I also used thicker steel tubing, instead of sheet metal so in theory it could dampen more. I think it sounds ok. 

May post a video if i haven't done so already. 

I'm in Norway, so making these for someone in USA will be unessesary expensive...🙂 

[Pullstart 65,391]

Yes, videos in action please @zlimmy!

[MikMacMike 488]

On 12/15/2019 at 5:33 PM, zlimmy said:

As i don't have reference, i'm not 100% sure. But i did make it almost exact as the rusty orginal i had. I also used thicker steel tubing, instead of sheet metal so in theory it could dampen more. I think it sounds ok. 

May post a video if i haven't done so already. 

I'm in Norway, so making these for someone in USA will be unessesary expensive...🙂 

Now you saying that!!!!! lets say there was half a dozen or a dozen members that were interested It will exponentially reduce the cost, well I would think anyways. I did the exact same thing when I 1st acquired Big Red from my Unc....except I did mine out of galv exhaust pipe......NEVER again....youd think a few decades of welding might have taught me to stay away from Galv.....But I was in a hurry and it was cheap.....I got sick for 2 days barfing. I am going to make another muffler but this time straight steel or if I feel adventurous may be stainless???? Mine wont be any use to anyone because Ill be incorporating it into the cooling system so I can draw heat from it for the cab like the old Vulgar vagons...(VW bugs) used to have.