Generator Muffler Mods

Gdetrailer wrote:
The OP started this thread back in the beginning of Dec, only posted once and most likely has left.

I'm still here, just reading the post and thinking.

its a basic box.. if materiel is fairly strong.. just glue or make thin frame from wood.

think of a dog house... many plans for them... just adjust for size.
flat roof or peak... also hinge roof and front door..

I made one for Home generator.. hinged front and roof.. for running generator..
I used angled roof... for better rain-off.
I attached roof to front with hinge... and both lift up and hook up forming a A shaped roof when open.

because I did not care about weight... I used plywood.. and vinyl siding for looks. an real roof shingles for roof.

I bought some fiberglass insulation board from our local hvac store, its the stuff they make heating duct out of. I think it will work good. i'm now searching for ideas on how to build it. I have one of the good highly respected Champion generators.
Jay D.

Is there a link to SoundGuy's quiet box?? It will not fix a crummy generator, but it will mitigate the problem.

I found for my needs that having two different gens is a better way to go.

I have a 10yr old Chinese knock off 4Kw gen (similar to a Champion) that I take with me on my camping trips. Noisy but much quieter than the old Briggs type contractor gens.. It has 120V only output which makes it ideal for my TT. I use it only while traveling for food stops at rest stops or parking lots and sometimes to cool down the trailer for an hr at a WM parking lot for the evening..

Never would consider firing it up in a campground but public places like rest stops or parking places are fair game..

Due to my water well requiring 240V the 4Kw gen just won't work so a yr ago I finally bought a HF 8Kw gen to power a transfer system with priority circuits like lights, furnace and water well.

Fortunately I have a separate small one stall detached garage that I was able to place the HF gen in. The garage building is uninsulated but is all wooden structure. The garage does a great job of shielding the noise and with less than 20 feet between the house and garage you cannot hear the gen inside the house.

Totally happy with the setup.

Now if I was planning to camp in a campground and run a generator, I would then have to consider going with an inverter type..

I am not into ruffing it, and specifically look for camping with at least electricity included mainly because I don't feel like dealing with feeding generators or spending tons of money on solar for the short amount of camping I do per yr (two weeks tops).

My vacations are for walking away from hassles, not making more work or hassle for myself.

Just be aware, use of your contractor gen might make you very unpopular in a crowded campground.. NASCAR race, you might be able to get away with it, but busy campgrounds, not so much..

Yeah, unpopular is minimizing the effect. I don't know what the combination in this genset really entails but the result is a very aggressive noise floor. On the few occasions I've used it at the house for power outages, I park it on the far wall of our detached garage. It is still noisy but is tolerable, considering the circumstance.

When power is restored on the lines and I turn the beast off, my ears and brain experience an almost 180 ringing. Hard to describe but it's not just the sound of quiet inrush again but as if the atmosphere became almost like a vacuum. It's probably due to the subsonic vibrations conditioning my brain after days of operation.

I may have to sell this genset to recover some of the price and get a Champion inverter set. That way, I can bring it on the road for camping, should the need arise. The Workhorse is dependable and it's hard to get rid of something that works so well.

Right now, my batteries, inverter, and solar are my power plant when away from a pedestal. That system works very well, is silent, and eliminates the need for carrying fuel. Heck, I may just get more battery and solar generation. That doesn't cure days in a row of bad weather, though

westend wrote:
I own this same generator. I use it on job sites and at home for emergency power. There are no heroic measures that are going to quiet this beast. It is one of the loudest generators I've owned.

A muffler retrofit is going to quiet it some but there is still going to be a racket. A better solution might be to use a long, heavy cord and park it at a distance.

The OP started this thread back in the beginning of Dec, only posted once and most likely has left..

Westend is correct, the noise from the muffler is such a small part that it will make virtually no change to the sound level of this type of generator.

I have a 8Kw Harbor Freight gen for my whole house setup, I connected a short flexible tail pipe to the muffler to vent the exhaust outside my separate garage building.

The sound coming from flexible pipe that exits the building is extremely quiet, in fact 10 ft away and you simply would not know that a 13 HP aircooled engine is running 3600 RPM..

Now, if you step foot into the garage building with this gen running you BETTER have HEARING PROTECTION ON. It is extremely loud inside the garage.

You can put the worlds most quiet muffler on it and it will not change the noise level, all the noise coming off this type of gen is mechanical in nature and is completely normal and expected.

The bigger gen, the noisier it will be, just the nature of the beast.

Smaller low noise gens often have special design considerations which are implemented in the body of the engine. Often vibrations are dampened via certain reinforcements in the correct places internally in the engine block..

Something that cannot be added after the fact.

Extremely long extension cord and or a structure like a three sided box can often provide some noise reduction..

Just be aware, use of your contractor gen might make you very unpopular in a crowded campground.. NASCAR race, you might be able to get away with it, but busy campgrounds, not so much..

I own this same generator. I use it on job sites and at home for emergency power. There are no heroic measures that are going to quiet this beast. It is one of the loudest generators I've owned.

A muffler retrofit is going to quiet it some but there is still going to be a racket. A better solution might be to use a long, heavy cord and park it at a distance.

I like Champion 5500 more than Generac. :)But I would buy Generac. However, portable ***Link Removed***generators take a lot of abuse. If you don't know EXACTLY how well it has been maintained it is a gamble. I'd get the Generac and take care of it from day one.:D

generacs are good until they need parts or a tech issue comes up. their cs is horrible from what ive read on other boards. look at ratings, go to the 1 star list and see why people give that 1 star. with generac its typically a parts / cs issue. i called champion once with a couple of questions they couldnt have been nicer and i got all the info i was looking for.

1stgenfarmboy wrote:
I built a quiet box many years ago for a friend, I used egg foam on all sides and put some furnace filters on the top, I installed a small fan to run off the genny for cooling, as well as a good small car muffler, I made the sides twice as tall as the ganny was.

It was alot quieter and made it OK to be within 50 ft of it, however this is big and bulky and not very practical for RV use, and it will still make your camping neighbors want you gone.


It would be good for your home back up genny.

With the high sides directing the noise skyward probably was the most help. It is difficult to absorb the sound so a simple folding structure for directing sound might be something for the inventors on here.