[Jag Daddy]

OK I want to buy a medium size generator for the shop, 3500 to 6000 watts. I want to make the engine on it run fairly quiet when running. Could I make an adapter for the exhaust and use a car muffler to get the noise level down? Or maybe even make something custom. I'd like to get it to where it's almost undetectable. Any ideas?

Regards
Mark:thumbup:

 

[julmer]

cheap = noisy, expensive = =quiet.

Much of the noise on a small air-cooled engine comes from the cooling fins and there isn't a lot you can do about that. If you really need quiet, look for a generator built for RV usage. Most of them run at 1800 RPM verses 3600 for the inexpensive ones and are designed from the beginning with quiet in mind. They will also outlast the cheaper units by several times. New ones are pretty pricey but used and takeouts can be has for a lot less. Check a local RV junkyard.

You can add a bigger muffler to the original and soften the bark a bit but it won't help all the other noise it makes.

 

[Canadian Charlie]

To buy a quiet generator you will be spending major cash

 

[Kevin45]

Hey JagDaddy...why are yo wanting a generator for the shop? Don't you already have electricity or you wanting it for backup? Just curious.

Kevin

 

[Jag Daddy]

Well a couple reasons backup for sure, in the summer out here if the power goes out your in 100+ weather it's nice to be able to fire up an air conditioner. Second and probibly the biggest, is I want to run my Christmas light disply off it. Figure I could save a ton of $$$$

Regards
Mark

 

[daimon1054]

Expensive does not mean loud. I would go for the largest you can afford and a car muffler is not a good idea the size is to large. Most of the noise it not from the exhaust but internal mechanical. Build a sound enclosure to block noise from the building then look for a motorcycle muffler to add to it.

 

[julmer]

Be darned careful about putting any kind of enclosure around an air cooled engine assembly. If you keep all the sound in, you may keep all the heat in also and you will end up with an expensive crispy critter.

I was at an RV site the other night. 5KW RV unit brand new is about $3000, Used should easily be less than 1/2 that. Also, all the RV style ones are electric start - that's a nice feature.

If you were to use a car-sized muffler, you would want to leave the stock one in place to generate the proper back pressure for the engine.

 

[fourbyfourblazer]

I use to build 1400amp movie generatos and we enclosed the motor & generator with an aluminum housing with one 1" layer of foam with vinyl or urethane barrier and 1" felt. I've seen another successful generator company use felt exclusivly on their generators to reduce sound. Perfect for big diesel/turbo motors so smaller generators will not be a problem.

On certain generators a sound baffle is made from several levels on top of each other at 45 degree angles for incoming air, covered with felt, this reduces noise significatly on the intake side. On the exhuast you can do what one of our competitors did by making a hole through the housing for the exhaust pipe and put a rain cap over it. Electric acuators open up doors on top when the motor starts for proper intake and exhaust of air. Here are some pictures of generators I helped build. These generators were so quiet you didn't know they were operating when you were only 75 feet from it.

 

[daimon1054]

Be darned careful about putting any kind of enclosure around an air cooled engine assembly. If you keep all the sound in, you may keep all the heat in also and you will end up with an expensive crispy critter.

I was at an RV site the other night. 5KW RV unit brand new is about $3000, Used should easily be less than 1/2 that. Also, all the RV style ones are electric start - that's a nice feature.

If you were to use a car-sized muffler, you would want to leave the stock one in place to generate the proper back pressure for the engine.

Your right about locking in heat, I was a litle vague. All you need is 3 sides and a partial top to reflect the sound away from the shop. Keep the walls about 1 foot from the generator so the air can move.