http://www.alpharubicon.com/altenergy/gensetquiet.htm

When the lights go out here in Virginia, you can hear the generators run for miles away. I looked around for ways to make mine more stealth because I dont want to advertise that I have power at times when times are bad.

I found this to be the best option and you can get a old car muffler from any junk yard for next to nothing.

More things to think about: If you worry about the smoke/steam from the exhaust giving you away in cold weather, even if you've managed to effectively silence the generator, run some more hose from the muffler output into some nearby bushes, where it will dissipate. Or run it up and connect it to the same point where your dryer vents, so it's not something your neighbors wouldn't be used to seeing.

I once saw how to plumb the exhust into a 55 gallon drum that was buried and had about 20-25 gallons of water in it. It was quiet, quieter than this set up.

WOOOOO Cowboy. I need to see this setup. How did you do it? I guess its a pipe that feeds down into the water? Then its just a bubble sound for the most part? I like that idea. I got a stock tank I can run it into now that I think about it.

You got it right. Bury the drum upright. Ad the 'intake' pipe down inside the drum so that it is just a couple of inches above the bottom of the drum. Add enough water to cover the opening by about 6" maximum. Add the exhaust pipe so that it is above ground about 6".

The exhaust enters the intake pipe. When the pressure gets just high enough it bubbles up thru the water, which cools and dampens the exhaust. It then exits thru the outtake pipe with little to no noise or smoke. If it starts to get a little noisy, simply add more water.

It can be improved by burying the drum about 15' from the generator and making sure that the entire exhaust pipe is also buried about 6".

Placing the generator in a small equipment shed will further lessen the sound.

There is another way to increase the sound absobing of the unit. BOth pipes are inserted into the drum and both openings are below the waterline. I'm not too clear on how far below the line they are.

Good to know Rudy. I think I am going to go with this method and I have a few 55gal drums to play with as well.

I That is a pretty darn good idea, I wonder what if any problems you might have with the resistance of the water pushing back on the outflow of exhaust?

That's why you only partially fill the drum. The deeper the intake pipe is in the water, the more pressure needed to operate.

Too much water and it would be like the old potatoe in the exhaust pipe trick.

Yeah that was my concern, had a thought of me standing outside shaking my head because my main power source was down... Thanks

Yep. The other part of it is that the longer the pipe, the more time the exhaust gas has to cool, and thereby the more tendency it will have to fall. When it contacts the water (which will presumably be cooler than the gas), it will (in most cases) become sediment, instead of exhaust gas/smoke, and settle to the bottom of the water naturally. Or at least part of it will. I think.

*gets his engineering book*

So in theory then I would be able to run in the middle of winter and not give off any heat signature?

In Europe, you could find the CPs by looking for the only barn in the town without snow on the roof.

You got to think about both heat and noise - sandbags are a wonderful thing.

Right, so you would cover your shelter with an extra insulator (ie: sandbags or Sod)? Or just better to dig in and use earth bearmed style. The genny itself can be dug in as well, which should cut down if totally eliminate the noise factor.

And keep in mind you'll want to add some antifreeze to keep your water from freezing or your whole setup is useless. Great ideas though. Many commercial generators wrap the exhaust pipes in thick insulation to lessen noise too.

It works.
The water does indeed deaden the sound.

Thanks for the reminder of the antifreeze.