QUIET Exhaust - Listeroid - HOW?

[carlb23]

I took an old 20lb propane tank and cut a hole in the top and bottom.  I welded threaded pipe couplings to both ends and i run the exhaust into one end and out the other.  it acts like an accumulator and allows the release of exhaust gases more slowly.  behind that i have a 2.5"diameter  car muffler and the exhaust pipe goes outside from there.  Outside i transition to a 15" length of 4" pvc that is on the ground with a reducer at the other end back to 2".  You can't hear the exhaust 25 feet away at all.

[George A]

Since my wife.........and the neighbors.........object to the sound of my 6/1, I've been thinking about using a propane tank also, but with a slightly different setup.

Note: The wife's objections are toned down a bit when we still have lights/t.v. and everyone else doesn't.

My idea is to run the exhaust into the side of the tank, at the top. Then, a second pipe will be located at the top and extend all the way down to the bottom, but about one inch from it. The idea is to have the exhaust enter and begin swirling a bit, as it travels to the bottom where it can begin exiting back up through the other pipe. A rain stack and condensate drain would complete the assembly.

I have no proof that such a setup would be better or fool proof, but it WOULD circulate, cool and let the gasses expand before exiting. Somewhat like the old cyclonic air filters worked. At any rate, it HAS to be better than that "pepper pot" muffler that came with the engine!

[gadget]

Saba, thanks for the pic and drawing. I was thinking it could be done with one chamber but I see you had 4 in the drawing.

If temps are low enough, I wonder if egg krate foam shape could be used to line the inside of the box. The foam is great at absorbing sound waves and the spikes shapes are good at breaking up the sound waves.

There is also the air pulse to deal on top of the sound waves. I'm guessing from everyones comments, the key elements are a large chamber(s) and some sound absorbing material liner.

[George A]

Why not try some R-max instead? R-max is a stiff, foil covered foam available at most lumber yards and is used as insulation. It comes in 4' x 8' sheets, 1" and 2" thicknesses. Easily cut and either glued or fastened with clamps inside your muffler.

[gadget]

Why not try some R-max instead? R-max is a stiff, foil covered foam available at most lumber yards and is used as insulation. It comes in 4' x 8' sheets, 1" and 2" thicknesses. Easily cut and either glued or fastened with clamps inside your muffler.

The foam should help dampen sound waves since we are only dealing with a low frequency noise. I like the idea of rock wool

[Jordan]

There's drawing from a Lister SOM booklet that shows an exhaust system that could be excellent.
Also, it looks like it would be cheap and easy to accomplish.

Jordan

[saba]

Hello Jordan, if you have a garden or place to dig a hole for sure that's the way to go.

[veggie]

Yes, the official Lister design using an underground concrete chamber is very effective.
https://www.youtube.com/watch?v=B2682AwYJ7w

[glort]

As long as the exhaust is as quiet as the mechanical clatter, that's all you need in most cases.

I really think the pit system is complete over kill. Get a decent large car muffler and you wont hear anything either especially if the engine isn't as enclosed and soundproofed as the one in the vid. I put a Muffler off a Subaru on my roid and you couldn't hear it and it's not even a big Muffler.

Other thing if the engine isn't enclosed is the intake noise. That was a lot more on my engine than the exhaust even when I just had 1.5M  of large Diameter pipe stuffed with a few pot scrubbers and necked down.  Again, used an airbox and filter from a car with the factory moulded and tuned intake ( for a 4 Cyl) and it hushed the intake up a LOT.

Intake and Exhaust are pretty easy to get so you can't hear them over the mechanical clatter these engines make.

[Hugh Conway]

I tried a few different mufflers, guess I didn't get the right one.
Dug a hole. the "pit of doom" works great for quieting things down.
Here's a link to an old thread about the "Pit" that contains 38AC, Bruce and others......
https://listerengine.com/smf/index.php?topic=7773.0
An air compressor intake filter works great, screws right in. Makes a huge difference with not very much expense.
Now, that noisy valve-gear!
Cheers
Hugh

[Hugh Conway]

Re the intake side of things:
An ancient thread that already has that solution, It works very well. There are other ways too, but this is as simple as it gets....just get a Solberg and screw it in.
Here's one:  https://www.solbergmfg.com/filters-traps-silencers/inlet-filtration-silencing/fs-ps-series/fs-19-150

Or different Mfg:  https://www.ecompressedair.com/eca-pfs-19p-150-air-intake-assembly-w-silencer.aspx
I 'm using that one.

Cheers
Hugh