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portable Generator Exhaust mods

wgm

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Jun 4, 2007
Messages
35
wondering if it is possible to add or modify an exhaust/muffler to reduce noise output for a 10k Generac Portable Genset?
-would adding something cause too much Back-pressure and cause operational issues?
-any suggestions to reduce the noise?
 
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Alchymist

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Most of the noise is from moving parts, more so than the exhaust. A sound deadening enclosure will do more to quiet it than muffler mods.
 

wayne55

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Oct 28, 2010
Messages
359
My situation was different, but I will still add this info. I have a 10 hp Briggs powered generator that I bought a new muffler to dampen the noise. It helped only slightly. Even with the "quieter" muffler, it is still pretty loud.
 

2manytoyz

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Sep 20, 2011
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Central FL
Most of the noise is from moving parts, more so than the exhaust. A sound deadening enclosure will do more to quiet it than muffler mods.

+1.

I learned this the hard way also. I bought a "Low Tone" muffler for a 4200W contractor grade model. It did change the sound to a more bearable pitch, but did not change the overall sound level.

Buy once, cry once. I went through $everal before finally buying a Yamaha EF2400iS. Very quiet, and sips fuel.
 

eldirector

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Sep 18, 2008
Messages
608
A lot of the smaller gasoline gensets are air cooled, so you can't really build too much of an enclosure. I have seen folks extend the exhaust into a bucket of water to quiet it down. I suppose that kinda works. I've also seen them plumbed into an car/truck muffler, which also kinda works.

An enclosure with sound-deadening material and baffles/vents, with maybe even a small cooling fan, might work. Add on a better muffler as well. Not exactly portable when done.
 

kbs2244

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Nov 11, 2006
Messages
14,065
Big muffler on a small engine will lower the noise.
The stock mufflers are puilt to a price point.
A small car muffler is big to a 10 HP engine.
 
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2manytoyz

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Big muffler on a small engine will lower the noise.
The stock mufflers are puilt to a price point.
A small car muffler is big to a 10 HP engine.

Well, that was theory many of us believed. However, try it yourself, and you'll quickly discover why expensive generators cost SO much. I'll give you a hint, it's NOT the muffler!

My Yamaha EF2400iS is only 53 dB. Whisper quiet. But the muffler isn't spectacular.

rbgen.jpg


http://www.boats.net/images/diagrams/yamaha/OPE/EF2400IS/IMAGES/EXHAUST.png

Part of the noise is the exhaust. Part of it is the noise of the intake. The rest of it is the mechanical roar of the moving parts. That last piece is where the money is on an expensive generator. Otherwise, we'd all buy cheap generators, and slap big mufflers on them.

Here's one of the previous generators I had:

pic4.jpg


Cheap spark arrestor type muffler. I bought a low tone muffler, which they now sell for $110 at Jacks Small Engine parts online. Take a look at the size of this...

muffler.jpg


37350.jpg


It did not change the overall noise level.

Here's what an airfilter looks like on a Honda 2KW:

airfilter_1.jpg


But many will take the same path I did. Buy cheap, fuss about the noise, modify it, fuss about the noise... later buy a quiet generator. But notice how few people buy a Honda or Yamaha quiet series generator, and wonder how to make them even quieter.

Good luck!

:beer:
 

scooterseats

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Mar 28, 2009
Messages
100
On small generators the noise level is almost inversely proportional to the price. Conversely the life span is nearly the opposite.
Bottom line, you get what you pay for. For occasional power needs buy the "Contractor Grade" units for long term power with noise levels that you can tolerate, buy one of the better brands noted for long life and low sound levels, ie: Onan, Honda, Yamaha, Kohler, etc.
 

malibu101

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Jul 1, 2005
Messages
3,908
Location
Walnutport PA
I was firsthand personally amazed at how quiet the Yamaha generators are,
At the NHRA event at Maple Grove there was a display rig from Yamaha power equipment. They had a big generator running their display trailer setting right next to thier display table. It showed that it was 240V and the load was ~40 amps on each leg.
That thing just quietly purred along. Standing literally next to it and you could barely hear it running.
In my opinion, unless you've seen/heard one of these in action you can not believe how quiet they are! But of course, when you see the price you expect something real good.

Disclaimer- I have nothing to do with Yamaha and I have an old Homelite 4500W generator that is so louder than a freight train.
 

Greatbear

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Joined
Jan 17, 2008
Messages
1,702
Location
Columbia/Fulton, MD
I have a huge Generac 17kW portable, and the exhaust is the least of the noise from that beast. The engine fan, the gen head fan, even the valvetrain noise contribute to the most noise from the thing. My old Coleman Vantage had more noise from the intake than the exhaust. A true "quiet" generator has not only a quiet muffler, but intake silencers, ventilation noise baffling, thick valve covers, etc. Some are also designed to run at "half speed" (1800rpm) using a four-pole generator head, while the best use a variable speed engine and an demand compensating inverter. All that makes for a pricier generator.
 

nehog

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Jan 2, 2010
Messages
7,935
Location
Jaffrey, NH
I have a military MEP-004 with an ASK (Acoustical Suppression Kit). This generator has a 200 CI four cylinder diesel engine. The ASK insulates the entire system, and directs all 'noise' straight up (exhaust points up, air intake and outlet are also straight up too...)

It is quiet, you can hold a conversation while standing right next to it. Open any door however, and the noise level is painful. Exhaust noise is not the problem, it is plain old engine noise.

Even if air cooled, you can build an enclosure for it--simply build one with an air circulation system (fans) so that air is moved as appropriate. It goes without saying that any installation should be sufficiently far away from buildings and flammable substances (tanks, etc.) to be safe.
 

djjsr

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Joined
Sep 4, 2006
Messages
4,796
Location
In the cornfields
I put a motorcycle muffler on the Generac I had in my racecar trailer. It helped a lot but it was still not as quiet as a Honda or Onan. But it was a cheap fix and my favorite color ......... chrome.
 
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