Need to quiet portable generator with additional muffler?

[12pack]

Lost power again.

I have an Onan 6500w portable generator. I need to quiet it down. I am looking to put an additional muffler or something to quiet it down. Some friends where thinking motorcycle, quad, tractor style muffler to add to the stock set up.

Anyone tried this already????

I know one of you guys has this figured out.

Thanks
Scott

 

[kensnelling]

I used a muffler off a Kawasaki KZ440 as an auxilary muffler to quiet down my B&S powered generator. Worked well until my ex-son in law "borrowed" the generator. Still have the muffler, need to buy another generator.

Ken

 

[RobertBrown]

It's cheaper and easier to build a small barrier that will absorb the noise after it leaves the machine.
I have fabricated efficient baffles from stryrafoam. Place it directly in front of the exhaust, with a piece of drywall in front, about 18 -24 inches away. Try to get in between he exhaust and the neighbor that complains the most.
Understand that when the power goes out it becomes very quiet, and no matter what you do your neighbors will hear yourgenerator if they don't have thier own.

 

[kenmac]

I would talk with Onan b-4 replacing or adding a muffler. That muffler was designed for that engine. If you add an additional muffler you could put to much back pressure on the engine causing damage to the engine

 

[Pete Judd]

I have seen people put the pipe coming out out of the muffler into a 55 gallon drum filled with water. Very effective in knocking the noise down.

 

[cqaigy2]

It's cheaper and easier to build a small barrier that will absorb the noise after it leaves the machine.
I have fabricated efficient baffles from stryrafoam. Place it directly in front of the exhaust, with a piece of drywall in front, about 18 -24 inches away. Try to get in between he exhaust and the neighbor that complains the most.
Understand that when the power goes out it becomes very quiet, and no matter what you do your neighbors will hear yourgenerator if they don't have thier own.

Something like this makes some sense. If you have a chance to look at one of those quiet honda generators, you'll notice they have sound absorbing material that enclose the generator. I had them remove one panel while the generator was running and the difference in sound deadening was amazing. My onan 6500 sits inside a smallish plastic building. I open the doors a little and point the exhaust out and the shed style roof opens to provide ventilation. This setup reduces the noise quite a bit.

 

[ray66v]

If the noise is coming from the generator, and not the exhaust pipe, an enclosure is your only hope to quiet it down.

I went through the expense of putting an automotive muffler on my Generac, and it did nothing to quiet it.

I have decided to put it in the barn, and close the O/H door most of the way. That quiets it considerably.

 

[Mickey_Fx]

What attempts have you made to isolate the noise between exhaust and engine mechanical noise? I know that for my Onan 4kw genset in the RV, much of the noise is mechanical. Any change in trying to quieting the exhaust noise does nothing for the mechanical noise.

 

[RobertBrown]

If the noise is coming from the generator, and not the exhaust pipe, an enclosure is your only hope to quiet it down.

I went through the expense of putting an automotive muffler on my Generac, and it did nothing to quiet it.

I have decided to put it in the barn, and close the O/H door most of the way. That quiets it considerably.

Enclosures present a different set of challenges. The biggest one is heat. If this enclosure traps heat, you are left to find a way to dispense with it.

 

[Travelover]

I put a small car muffler on my Coleman 5000 watt generator and it knocked the exhaust noise way down. The bad news is that there is still a lot of noise radiated off the block. My neighbor built a wooden "doghouse" for his generator lined with fiberglass insulation and vents that are staggered to prevent a line of sight exit for noise. He also added a 20 inch box fan to force ventilation. It works pretty well but is awkward to use.