dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
6670
share rss forum feed

cjski
The Wheel Weaves As The Wheel Will
Premium
join:2001-01-04
Sun City, CA

Help w/generator noise

To go along with all the other genny threads we have in here...

I have 1 of those inexpensive chinese gensets. Normally I don't care about the noise it makes, because were out in the desert, but tomorrow the wife and I are going to take the trailer to the beach. The setting is a large parking lot, and the spaces are 1st come 1st served...

Packed in like sardines!

What I want to do is make a full 5-sided enclosure to throw over the genny to kill a lot of the sound. I went down to HD to get an idea for materials and I can't decide whether I want to use doubled-up ceiling acoustical tiles or 1" rigid insulation for the box...I'm leaning towards the rigid insulation-even maybe doubling that up too.

What do you guys think?

What would you guys recommend for air flow? Maybe a 12v fan connected directly to the genny's 12v outputs? Can I extend the exhaust with a small peice of PVC? Keep the box a couple of inches off the ground for air flow?

I'm trying to do this quickly, and on a budget, so any ideas you guys may have...??

Oh, and where can I find a small, cheap 12v fan?



Ken
Premium,MVM
join:2003-06-16
Markle, IN

rigid insulation is flammable and releases toxic smoke, I would not use it at all. Use something that is more fireproof like fiberglass or rockwool. Ceiling tiles are generally fiberglass so that would probably be better, but check out how fire proof they are before you commit to this project.



tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
kudos:5

You do NOT want to use PVC or anything plastic connected to the exhaust.

However, you could make a pretty cheap glass pack muffler for it... If you are familiar with sheet metal, all the better.. You`ll need a set of sheet metal shears, 2 feet of 3" galvanized pipe, 2 feet of 6" galvanized pipe, and 2 6" caps. Drill a lot of 1/2" holes in the 3" pipe, then cut 3" holes in the 2x 6" caps. Trim the 6" pipe so its 2-3" shorter than the 3" pipe, insert the 3" pipe into the 6", then stuff lightly with fiberglass insulation (no paper backing). You`ll need to run this and heat it up to burn any oils off before taking it to the parking lot.

Attaching it to the generator is another thing, but I pretty much guarantee this muffler will bring down the noise at least 50%

-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!)


TheMG
Premium
join:2007-09-04
Canada
kudos:2
Reviews:
·NorthWest Tel

1 recommendation

reply to cjski

There really is only one proper solution: buy a quieter generator.

Building an enclosure around the generator is a bad idea, there is a fairly high risk of overheating. With a high airflow fan, the risk of overheating can be decreased, but not eliminated. Also, much of the efforts to dampen the sound will be lost since noise will escape through the ventilation openings.

Quieter generators generally:

-operate at lower RPMs
-have vibration dampening mounts for the motor
-have better mufflers
-are enclosed in metal panels with high temperature sound dampening material, designed to allow proper airflow to the engine using forced air cooling

IOW, there is no substitute for purchasing a quieter generator to begin with.



chamberc
Premium
join:2008-08-05
Irving, TX
reply to cjski

Have used fully enclosed boxes over generators for 15-20 years for tailgating... works fine, no worries. Just leave a small port for intake and exhaust and you'll be fine.



John97
Over The Hills And Far Away
Premium
join:2000-11-14
Spring Hill, FL
Reviews:
·Bright House
·ooma
reply to cjski

They do make quieter mufflers primarily for generators that fit various small engines. Assuming your generator has one of the Honda clone engines, you may be able to find a quiet muffler for a Honda that will fit.

That's the approach I would take and I would consider that a proper solution.
--
So put me on a highway, and show me a sign.
And take it to the limit one more time...


bemis

join:2008-07-18
Reading, MA
Reviews:
·Comcast

said by John97:

They do make quieter mufflers primarily for generators that fit various small engines.

While not a bad idea, it may not solve the problem because a surprising amount of generator noise is unrelated to the exhaust... the intake, valves, heads, alternator itself--all make a pretty good racket.


Kramer
Premium,Mod
join:2000-08-03
Richmond, VA
kudos:2
reply to cjski

See this guy's mod. »joelsgarage.blogspot.com/2006/03···ler.html

I'm not recommending it, but linking to it to emphasize the fact that even after attaching a huge muffler he still experienced a good degree of noise coming from the engine itself. The noise isn't all exhaust. If you build a box, you might consider attaching a frame of aluminum right angle bars or steel for something heavier but cheaper. Attach panels of 1/4 inch cement tile backer board possibly backed with some support like sheet metal. You can easily cut air intake and exhaust holes. If you restrict air flow enough, you are going to overheat it. I would think you would want to pump a lot of air into the cabinet to keep it cool. The problem is, how do you do this without making a hole so large as to defeat your goal of keeping it quiet. I don't see a 12v fan being anywhere near adequate. An inline fan attached to some 4-6 inch round duct may provide enough outside air to keep it cool. »www.google.com/products/catalog?···0CA8QrhI a 6 inch cut in the panel is going to release a lot of decibels of noise. You might try looking for a smaller fan.

The experts at keeping generators quiet are in the movie industry. I worked for a company that rented a generator panel truck that ran a huge arc light used in cinema. The truck was filled with 75% muffler and 25% generator. I would just wildly estimate there was hundreds of cubic feet of muffler winding back and forth. They run so quiet you can barely hear them ten feet away. I'm sure the generators are water cooled. There is probably a lot of good info on the net from RVers too.

Be careful with heat here. You want to use 100% fireproof materials. It is one thing to burn up a generator but a lot worse to start a major fire.


laserfan

join:2005-01-14
Texas
reply to cjski

said by cjski:

I have 1 of those inexpensive chinese gensets... tomorrow the wife and I are going to take the trailer to the beach. The setting is a large parking lot, and the spaces are 1st come 1st served...Packed in like sardines!

Well the OP is gone, but I hope I'm not parked next to him, because it doesn't matter whether he buys an expensive new generator, or just attempts to sound-proof his own. I'm gonna be pissed if he runs it at night.

The joy of camping--people w/gensets!


shibbyshabaz

@shawcable.net

Based on The OPs description of the setting... large parking lot, first come first served.... I don't think anyone has the right to complain about anyone else. If it's just pull in where you want and camp for free then one guy has his music going, the next a generator, the next a barking dog.... it's just the way it goes.

We random camp in the mountains and for the most part it is empty where we go. Every now and then it is busy though and everyone has no choice but to be tolerant to how everyone else does it. I do run a generator sometimes, I also have a couple dogs that like to chase some of the wild life around and I like to rock out with my tunes for a good portion of the day. I don't feel one bit guilty about it because I'm not giving my neighbor a hard time about his two stroke dirt bike and 97 kids.

One thing I don't understand though is those who feel the need to run their generators 24/7 while camping. My cousins do this and I think it is unnecessary, we will fire up our gen if we need to charge our phones or give the quads a quick pressure wash but other than that we are happy just chilling out with whatever the battery provides.


nonymous
Premium
join:2003-09-08
Glendale, AZ
reply to cjski

I had never been camping and went this summer with my son. Yes generators at night kill the camping experience.
The waves on the beach or the animals and insects other places just not the same.
For night and low use generator to batteries to charge then an inverter and shut off the generator.



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting
reply to cjski

The first best option, as someone already mentioned, is to get a quieter generator.

The second best option is to add a real muffler to the one you have.

A generator enclosure should be fire proof and adequately ventilated. This doesn't work well for air cooled engines at all. Normally enclosures are reserved for water cooled engines.
--
I just might be the most "licensed" S.O.B. you know.



beck
Premium,MVM
join:2002-01-29
On The Road
kudos:1
Reviews:
·Stablehost.com
reply to cjski

Even those of us with quiet generators hate the noisy ones! Especially in the desert. The noise carries for many miles.

Get a nice quiet little honda generator or something. They are so quiet nobody whines about them.
--
Some people are like slinkies - not really good for much.
But they bring a smile to your face when pushed down the stairs.



AVD
Respice, Adspice, Prospice
Premium
join:2003-02-06
Onion, NJ
kudos:1
reply to nunya

said by nunya:

The first best option, as someone already mentioned, is to get a quieter generator.

The second best option is to add a real muffler to the one you have.

A generator enclosure should be fire proof and adequately ventilated. This doesn't work well for air cooled engines at all. Normally enclosures are reserved for water cooled engines.

It would also need to be water resistant
--
Standard disclaimers apply.
Atomic batteries to power. Turbines to speed.


jjoshua
Premium
join:2001-06-01
Scotch Plains, NJ
kudos:3
reply to cjski

Look at your owner's guide for ventilation requirements.



AVD
Respice, Adspice, Prospice
Premium
join:2003-02-06
Onion, NJ
kudos:1

"required is ventilation compiant with special publication 22.76.2011 of PRC Directorate of Cumbustion gadilanes."
--
Standard disclaimers apply.
Atomic batteries to power. Turbines to speed.


CTMustang
Premium
join:2007-09-10
France
reply to cjski

»www.youtube.com/watch?v=T5V_MU2SxQA


The problem as shown in this video is what I face.

It's not the exhaust that's loud, it's the rest of the machine.....unless you go with a honda that I assume has roller bearings in every little nook of moving parts, you really can't fight the noise


Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand
reply to cjski

said by cjski:

To go along with all the other genny threads we have in here...

I have 1 of those inexpensive chinese gensets.


I own the houses on either side of me as investment property.

This last bout of power issues with Irene got me thinking about something to power all three if another power failure should occur (which is most likely) . . . .

In the past, I have worked with generators in ship board installations and favored the Kohler solutions over the competition, so I started looking their.

I narrowed the choices down to a 20 KW industrial diesel which produces 68 decibels at 7 ft. I believe that should do the trick but I'll have to question the engineers first to determine if it's the correct choice.

Crescent
Premium
join:2003-01-22
canada
Reviews:
·Eastlink Cable
reply to cjski

You have the generator, I hope it was cheap.

Best is a quiet quality generator, but yours works! No need to get one.

Heavy boxes absorb more sound. Lighter construction methods, done on expensive industrial units are expensive to build.

Build a cheap heavy box out of what ever. Try to keep the cost down.
If it works, great! just have a mounting spot for a fire extinguisher, they are cheap, and good to have around.

If it kills the gen set, you now have an excuse to buy a quiet gen set.



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting
reply to Coma

I've always been impressed with Kohler stationary sets. They are definitely a step up in quality.
On the other hand, I used to have their old 4.5 kW air cooled units on 2 trucks for hydraulics / generator. They sucked dirty butt. Those things blew through control boards like they were going out of style.
--
I just might be the most "licensed" S.O.B. you know.



iknow

@optonline.net
reply to cjski

2 large car mufflers in series, and reduce the outlet size to 1'', and the exhaust sound is GONE! a few feet away. then if needed, COMPRESSED fiberglass inside a metal enclosure will take care of the rest, you'll need one side open for air circulation, but the compressed fiberglass will still absorb the sound. BTW, fiberglass that is not compressed makes a good thermal insulator, because of the air that is trapped, but for sound proofing, it HAS to be compressed to work the best.


Crescent
Premium
join:2003-01-22
canada
Reviews:
·Eastlink Cable
reply to cjski

»www.smokstak.com/forum/showthrea···?t=58379
I owned one of these, based on the Wisconsin 30 hp V4 gas engine, it was converted by Schramm so 2 of the cylinders pumped air, as a air compressor, the other side was the gas engine.
It pumped air like a mofuckr
Fine pic of American Iron! 1957 unit, I did a complete restoration on it, making air valve parts for the now defunct Shramm conversion part.
Maybe there were parts, but this was 1995, I was too busy polishing the brass on it to know much about the Internet.

It was LOUD!
One car muffler made it so I only needed ear plugs, not ear plugs and ear muffs.
2 car mufflers made it not so bad in outside the 3 sided box I made from scrap refrigeration truck panel boards

2 car mufflers, 2 flex couplings, and a bunch of other supports, it still broke the substantial exhaust manifold.
Something else to weld up AGAIN! gosh darn pile of rust!
Wonderful machine!
I abandoned it like the last owner.



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to iknow

Internal engines are designed for a certain back pressure from it's exhaust system and altering it by installing homemade exhaust systems will effect the performance and life of the engine.

Manufacturers would put big mufflers on their engines themselves to quiet their engines if it was that easy to do.



49528867
Premium
join:2010-04-16
Fort Lauderdale, FL
kudos:3
reply to cjski

said by cjski:

What I want to do is make a full 5-sided enclosure to throw over the genny to kill a lot of the sound. I went down to HD to get an idea for materials and I can't decide whether I want to use doubled-up ceiling acoustical tiles or 1" rigid insulation for the box...I'm leaning towards the rigid insulation-even maybe doubling that up too.

Personally I think ceiling tiles would be a major mistake as the vibration of the generator will tear them up long term.

I have built a few generator housings and found Owens Corning 703 FRK to be very good at providing a substantial level of noise isolation.

»esh-docdb.fnal.gov/cgi-bin/Retri···tion.pdf

The 703 FRK is a 2” foil back backed sound absorbing material which can be installed to the inside of a plywood or fiberglass shell housing using standard two part marine grade epoxy resin.

I installed it with the foil Kraft side facing the engine to preclude the absorption of oil and the joints can be sealed with standard foil duct tape providing a nice tight oil resistant enclosure.

What would you guys recommend for air flow? Maybe a 12v fan connected directly to the genny's 12v outputs?

I used an attic ventilation fan that I re-motored with a lower speed 240 volt motor, since you want to run 12 volts you would probably do best with a small automotive radiator fan, remember air cooled engines like a lot of air to keep cool a small 12 volt fan is not going to cut it .

Can I extend the exhaust with a small peice of PVC? Keep the box a couple of inches off the ground for air flow?

Absolutely not! You will need steel tubing for the exhaust and while we are on the subject of exhaust consider buying a muffler for an Onan camper generator they have small inlets that are considerably easier to match up to the existing exhaust tubing.

Wayne.
--
It is sobering to reflect that one of the best ways to get yourself a reputation as a dangerous citizen these days is to go about repeating the very phrases which our founding fathers used in the struggle for independence. - Charles A. Beard

itguy05

join:2005-06-17
Carlisle, PA
reply to cjski

You may want to spend some quality time with this thread:
»www.rv.net/forums/index.cfm/fuse···1645.cfm

It's from the RV guys who also want powerful and quiet generators. I've been reading it on and off for a while and there are quite a few that have made enclosures for their generators.



battleop

join:2005-09-28
00000
reply to bemis

I've read several sites that were about taking motorcycle mufflers and fitting them to generators. Most of them say that you can reduce the sound a little but it wasn't worth the effort because of the noise the generator makes.


laserfan

join:2005-01-14
Texas
reply to cjski

We've not heard from the OP but maybe he's gone for the weekend.

I'll say only that many campgrounds have rules that gensets should not be run after X o'clock, and I will call the management if anyone violates those rules.

If no rules exist, then I'd say that common courtesy applies. If you're down South and it's 90 at night and all your neighbors are locked-and-loaded (with A/C and gensets going full blast) well that's one thing. If you're the only genset user among a camp-full of tents, then you respect their quietude (and turn your genset OFF of course, no matter how quiet you might think it is).


bemis

join:2008-07-18
Reading, MA
Reviews:
·Comcast

said by laserfan:

If you're the only genset user among a camp-full of tents, then you respect their quietude (and turn your genset OFF of course, no matter how quiet you might think it is).

+1 on this, running in your back yard during a storm is one thing. A recreational campsite is a whole other ball of wax.

No matter how quiet your generator is, if it's not 100% noiseless it will be VERY noticeable at 11PM when the only other thing making a noise is wildlife...

Crescent
Premium
join:2003-01-22
canada
Reviews:
·Eastlink Cable

+ 2

There are so many sites I know of, and go to, that there is no engine driven anything for 5 mile radius.
I might have them, but they are off!

It keeps me from "doing something" about the thing I was getting away from, NOISE!

Am I fortunate to live in an area that I can find these places?
NO, at a great loss in income, I moved here from the other side of Canada.


CTMustang
Premium
join:2007-09-10
France
reply to cjski

yeah, for sure, dont use a generator at a damn camp site!