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Making the genset quieter
#1
Hey all,

I just took delivery of 1234.  This one has the PT 20kW, side mounted.  My understanding is that they did a few side-mounted units in this timeframe (2008ish) and then went back to front-mount, maybe because they didn't get much quietening, and of course because people like having the full second bay.

Anyway, my impression of this generator is that the engine itself is very quiet inside that hush box.  And inside the coach there is very little sound or vibration, which is awesome.

But sitting outside on the curbside, the blower still makes a pretty good bit of noise.  Also, it exhausts straight down under the coach, so warm air tends to come out on the camping side right where we're sitting.  I don't know if it's possible to do anything to make it quieter, but I'm interested in whether anyone else has tried anything.  (I'm also concerned about stirring up silt and sand when we camp in a dusty area -- we dry camp a lot, and some places are pretty dry.)

Thanks,

Ben
2008 Newell #1234
Boulder, CO

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#2
Ben,

I have never heard of a retrofit on the gen exhaust...but the two other approaches are : 1) Run the exhaust to the roof (this is how mine is done). And 2) Meet up with the Aquahot exhaust and take it to the back of the coach.

Where does your aquahot exhaust now? Could they join the exhaust pipe to the AH exhaust?

The folks at the factory redid my AH / gen exhaust when I caught the middle of the coach on the crown of the road. They were able to fabricate all the pipes needed.

Bill
Bill Johnson
2003 Newell #653 Quad Slide Cat C-12 engine with Motorcycle lift 
2011 Jeep Wrangler, 2016 1200GS Adventure BMW Motorcycle
Auburn, Alabama
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#3
You might try putting down a plastic tarp or mat on the ground to park front of coach over.
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#4
bill, i am guessing he means the hot air coming out of the genny compartment, not the actual exhaust. you know how the air comes out from the scoop under ours after it gets blown through the genny compartment?

tom
2002 45'8" Newell Coach 608  Series 60 DDEC4/Allison World 6 Speed HD4000MH

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#5
Tom,

Well duh!  You are correct.  I guess that makes more sense.  But the problem is still out there....does anyone have a solution?  On my coach, I have a front mounted genny and there used to be an elaborate shroud that directed the hot air under the coach.  When I had my "incident" with the tow truck, the shroud was completely destroyed.  Instead of rebuilding it, I opted for a simple guard that directs the air straight down.  The result is that the genny runs about 10F cooler.  

I wonder if this an issue for all side mounted generators.

hmmm.
Bill Johnson
2003 Newell #653 Quad Slide Cat C-12 engine with Motorcycle lift 
2011 Jeep Wrangler, 2016 1200GS Adventure BMW Motorcycle
Auburn, Alabama
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#6
Sorry guys, I was unclear. Yes, I'm talking about the air blowing out of what sounds like the generator area after that big remote fan sucks it in and uses it to cool the engine.

The air movement itself is a bit of a concern, and I will try a mat under there first to see if I can calm it down. The ultimate test will be the salt flats in Nevada at Burning Man next month, so I'll report back how that goes. (Yes, I have taken my previous coach to Burning Man. It made it through just fine with some care and precaution ahead of time!)

(I do have the ceiling exhaust option in my coach, although that exhaust runs up through the rear wardrobe, and we want to turn that wardrobe into a bed for our daughter. So we are going to revert the exhaust to the ground, presumably adjacent to the AH exhaust out the back.)

But aside from the dust, I feel like 90% of the noise outside is fan/air movement. I'm trying to figure out how Marathon gets their genset to be so quiet. Maybe they put the blower/output up on the roof or something to get it out of earshot?

Ben
2008 Newell #1234
Boulder, CO

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#7
Since it's only hot air being exhausted and not engine exhaust gases maybe you could use some type of flexible ducting to direct the air away from your patio area? Of course you would have to make some type of easy connector and that would depend on the shape of the exhaust and how easy it is to access. This site has quite a few different types of lightweight flexible ducts. http://www.ducting.com/hose-types/fabric-hose/
Forest & Cindy Olivier
2004 26.5' MB Lazy Daze
former owners 1998 Newell 45' 2 slide #486 

former owners 1993 Newell 39' #337 
2011 Chevy Tahoe RZR 570LE
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#8
Just so you are clear on the generator cooling system, I believe you have a horizontally oriented radiator with a squirrel cage blower mounted on the top side in a separate compartment.  The fan sucks air in through a louver on the door usually and exhausts air downward underneath.  The cfm requirement is enough to keep the coolant temp at a usable level under full load conditions.  The air flow does nothing to keep the engine / generator compartment cool.  That function is provided by another squirrel cage fans or pair of fans considerably smaller than the radiator fan.

Perhaps the radiator fan has been changed and is the wrong fan which would attribute to the higher noise level.  The fan as installed when new are typically not that noisy.  As to redirecting the output, maybe some sort of canvas boot could be used but that would always be a hassle to install and then remove when traveling.  The blowing sand is certainly an issue and the suggestion of a mat is another perfect guru idea.

I think I have the fan number from #785 (which was a 20KW PT) when I replaced it. if you need it PM me and I'll hunt it down.
Gordon Jones
2000-45'-2slide-#567
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#9
Don't the new ones with front mount gens still have that fan in the same spot?
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#10
Thanks guys. Yeah my impression was that the hot air was coming out of the fan bay rather than the generator bay.

Unfortunately, I listened to a couple of other side-mounted gensets while I was in Miami, and they sounded about the same as mine... so I am probably just sensitive to it. It is not super objectionable, it's just far from quiet. Somehow Marathon manages to make the whole system almost inaudible even when outside! I was thinking I would figure out what they do and copy them. Smile
2008 Newell #1234
Boulder, CO

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