Update - (Mission Fail) - Generator - Improving the muffler - ideas anyone?

[joe_momma]

My 11hp Briggs & Straton works fine as my emergency power supply. (Granted it is gasoline rather than diesel.)

The drawback is that the "stock muffler" from B&S does very little to quiet the engine. It is considerably louder than a lawnmower, and noisy enough that not only would it attract "unwanted" attention, but is literally too noisy to have near my house as a reserve power supply. (I first got it to use at unpowered construction sites.)

My thinking is to go to a muffler shop and have them weld on a secondary (automobile) muffler to reduce the exhaust noise.

I'd prefer to keep the existing stock muffler on (less machining to attach the secondary suppression system) and assume that the back pressure will remain unchanged (since an auto muffler handles much higher volumes and velocities of the waste gases).

Here's a link of the current muffler (for what it is worth)

http://www.amazon.com/Briggs-Stratton-491626-Lo-Tone-Horizontal/dp/B0038U3KB0


Do any of the BMs have experience or thoughts on how to approach this?

[StackerKen]

Joe; My generator is kinda loud too.
So I hope you get some good replys here.

I was thinking making an insulated box to put over it in a SHTF situation, when I didn't want to draw too much attention.

But I can't hear it when Im in the house so it isn't really necessary now.

[Heimdhal]

Joe; My generator is kinda loud too.
So I hope you get some good replys here.

I was thinking making an insulated box to put over it in a SHTF situation, when I didn't want to draw too much attention.

But I can't hear it when Im in the house so it isn't really necessary now.



Make sure it can still get air while in that box, or youll have to keep going out there to turn it back on.


(i am also interested in the quieting aspect as well)

I actualy need to go fix mine before the a 'cane comes along. My mom left gas in it for 2 years a few years back, come to find out.........

[Korbin Dallas]

A few years ago, my brother in law bought a 5000 watt gas powered generator to power a Christmas light display. He put it in the corner of his backyard, but it was still pretty loud.

We made a sound deadening enclosure for it using Plywood and sound dampening wallboard 3 layers thick with 1/2 inch air space between each layer. We created baffled air intake and exhaust ports as well.

It reduced the noise somewhat, but the vibration was too much, as the ground carried it to the house. At that point we gave up, and the kids used the materials for a fort.

[hoarder]

One way to quiet a generator is to build your house on several hundred acres and then put your generator as far away from your house as needed so you won't hear it. ;D

[Quixote2]

Google listeroid muffler and get ideas from the listeroid fans.

[Ironfield]

One way to quiet a generator is to build your house on several hundred acres and then put your generator as far away from your house as needed so you won't hear it. ;D


only problem with that is the sound would still draw undesirables even if you couldn't hear the noise in the house.

Regarding the vibrations carrying, rubber mounting pads should less the effects of the tremors. As others have suggested automotive muffler and sound deadening enclosure could help to mitigate the sound to a more tolerable level.

-Ironfield

[Saul Mine]

The usual tactic is to put the generator as far as possible from the house. Second best is an earth berm all the way around it. But the best way is to get a unit that is not so confounded noisy!

[undgrd]

Here's some good information. Also comes with a video to show how quiet it is. He should have done a before and after IMO.

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

Real Player Video Download (http://www.alpharubicon.com/altenergy/genset-noise.rm.ram)

[joe_momma]

Here's some good information. Also comes with a video to show how quiet it is. He should have done a before and after IMO.

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

Real Player Video Download (http://www.alpharubicon.com/altenergy/genset-noise.rm.ram)


Thanks undgrd - this is what I'd had in mind - good to see someone had taken this route!

[hoarder]

Some things to factor in...

When I worked offshore production platforms the exaust systems on engines were often piped a long way from the engine. So, for example, if we had a 3" exaust line from a 471 Detroit Diesel they would install a 3" to 6" adaptor near the engine and run 6" pipe the rest of the way with a gigantic 6" muffler. This is done because flow restriction is calculated on a per foot basis.

Also I noticed in the engine rooms of large work boats that they would wrap the exaust systems with a woven fiberglass tape about 2" wide and 3/32 thick. Then they would secure it in place with stainless steel wire to keep it from unraveling. This was done to transfer as much heat outside the engine rooms as possible but it also helped quiet things down. This is for interior applications only because the tape will hold water and cause exaust tubing to rust out faster.

[Liquid]

Excellent ideas in this thread. You could combine them all, muffler idea, building a containment box, ie...small engine room insulated with auto insulation, and have the exhausted piped out. Just make sure you have ample air intake, a vent somewhere.

[joe_momma]

Thanks for all the help!

I'll post pictures of my outcomes in next week!

(Ordered a sound level meter off Amazon - want to capture before and after effect.)

[undgrd]

Consider this as well. For maximum discretion, put the generator in your laundry room and use the flex tubing from the dryer, connected to the end of the muffler, to pipe the exhaust outside.

;)

[Heimdhal]

Consider this as well. For maximum discretion, put the generator in your laundry room and use the flex tubing from the dryer, connected to the end of the muffler, to pipe the exhaust outside.

;)


You'd have to have a pretty good seal, no? ;)

[Liquid]

You'd have to have a pretty good seal, no? ;)


You'd probably want a ventilation fan as well, and perhaps a co detector.

[undgrd]

Consider this as well. For maximum discretion, put the generator in your laundry room and use the flex tubing from the dryer, connected to the end of the muffler, to pipe the exhaust outside.

;)


You'd have to have a pretty good seal, no? ;)


You'd need an AIR TIGHT seal. It would be undetectable though.

[hoarder]

An air-cooled engine in a laundry room would over heat after 45 minutes. If the laundry room is 150 degrees a circulation fan would only circulate 150 degree air. Hot air would have to be removed from the laundry room.

A dryer vent in a masonry home would be OK but in a framed home it might be a fire hazard.

Or maybe I'm full of hot air! :D

[Liquid]

An air-cooled engine in a laundry room would over heat after 45 minutes. If the laundry room is 150 degrees a circulation fan would only circulate 150 degree air. Hot air would have to be removed from the laundry room.

A dryer vent in a masonry home would be OK but in a framed home it might be a fire hazard.

Or maybe I'm full of hot air! :D


If you installed a fan to vent the hot air out, you'd be OK. You'd have to allow the air to get pulled from the rest of the home.

Might be an issue during the colder months.

Either way...fire extiguishers are your friend. ;D

[joe_momma]

I don't have a laundry room :(

Safety comments -
I would not advise keeping anything like a generator or kerosene heater inside a residence - Carbon Monoxide kills people all the time - odorless & tasteless - you can be in trouble an not know it. I strongly encourage people to not use gasoline equipment (or charcoal) indoors.

Another issue is waste heat - a gallon of gasoline is about 36,000 kW - burning it in a hour releases 122,000 BTUs of energy - at least half of that is heat - the air cooled engines could easily overheat in a modern (air tight/well insulated) home.

[undgrd]

I agree with all of the safety information posted. I didn't mean to imply I've done or attempted these things. More or less just thinking out loud.

[Rockbrother]

what about putting the containment box underground? How much room do you need to give it to keep from overheating?

[joe_momma]

An update for any interested -

1) Got a new exhaust gasket
2) Purchased a sound meter - sound levels 1 foot from exhaust (110 dB) and at the plugs (108 dB)
3) Welded a flange to the muffler
4) Bolted on a car muffler (spent $10 at pick-n-pull)
5) rechecked sound levels - 1 foot from muffler (105 dB), 1 foot above the original muffler (110 dB), and at the plugs (110 dB)

Conclusion - putting an additional muffler on the engine did nothing to dampen the sound levels - presumably the thin walls of the OEM muffler are the issue.

Next steps - I may remove the OEM muffler, and weld a flange to to the exhaust pipe/muffler assembly to see if that improves the issue.

Additional findings - the exhaust pipes get REALLY hot very quickly! (ouchie)

Thanks all for the help!
:)

[Book]

only problem with that is the sound would still draw undesirables even if you couldn't hear the noise in the house.



http://www.gedyn.com/media/product-solar-collector-aet.jpg

Sell the generator and use that money to buy solar panels and batteries. WTSHTF you won't have generator fuel and even if you did the noise will attract zombies.

|--0--|

[hoarder]

On aluminum air cooled high RPM engines, no matter what you do with the exaust, you will still have engine noise.

[LuckyStrike]

The Honda Quiet generators are super quiet, we have a 2000 watt unit at work for running hand tools and stuff. It has a built in throttle that reduces RPMs while the unit isn't under load. You can easily have a conversation standing right over it. It's rated at 53-59db according to this site anyway.

http://www.hayesequipment.com/honda/generators/honda_super_quiet_generators.htm