Quiet your noisy truck generator

Quiet your noisy generator with an automobile muffler
Having a cabin in a remote area of Utah, I depend upon a generator to provide electricity. I
have a solar electric system, but for the high power tools I run the generator. I don’t mind filling
it with gas, restarting it, or even the maintenance. But the noise drives me crazy.
 
I have read articles in BHM about generator sheds to reduce noise, but I didn’t want to go to
that much work. Plus my generator needs to be portable as we work about the “ranch.”
 
Determined to try anything, I sought a new fresh approach. I thought, “Okay, if the small engine
dealers can’t (or won’t) come up with a solution, I’ll try someplace else.” I reasoned that the
small mufflers just don’t have the capacity (volume, size) to do anything about the noise.
What about taking an automotive muffler and somehow hooking it up? As an engineer, I
knew there could be dozens of technical challenges, not only in “hooking” the parts together,
but getting them to work t o g e t h e r effectively.
 
http://fastonline.org/CD3...0muffler...By%20Jo.PDF

A muffler will only go so far. Not all the noise from an open frame "contractor" can be silenced by a muffler. You also need to build a "sound roofing" enclosure.
 
Soundproofing a Generator is a good starting place. You don't need to buy their fancy foam, You can use products from Home Improvement stores. I have seen many enclosures that use the same principle that previous link uses.  I also downloaded the book the article references. (freebie) . Interesting read. Based on what I understood: A plywood box lined with "asphalt impregnated sheathing" like Homosote, Soundboard or Quietbrace (brand names) to give the impregnated sheathing support and a "soft" insulator (like one of the foam house sheathings)  over the impregnated sheathing would do the job. My interest in this is to quiet down an open frame contractor generator on our bus conversion. The 6K/6.5K generator I plan to install under our bus has a rating of 76dB and it costs under $400. Since the generator would be mounded under the bus under our sleeping area, I would like to quieten it down as much as possible. For us, I would enclose the outer part of the box and use screened vents in place of leaving the outer end open to the air.
 
Loud, open-frame, contractor style generators are big no-no's in the RVing world. I cannot see paying $2K to $6K for a generator that we will most likely only use a couple times a year. And most of the time only while traveling down the road.
 
For a small fairly quiet generator... I would put this one out there. We would (and will, once it's needed) buy it for the food cart. It should power the A/C unit and we have heard one run. We spoke to some folks who had one (for a couple of years) and they liked it. We were standing about 3 ft away from the generator while it was running. We did not have to yell over it and only raised our voices slightly.
 

Here's a link for some more info on isolation systems, don't forget about isolation mounts. Anechoic or acoustic foam may be an alternative also, but just make sure you use only materials that are fire proof, sorta obvious but thought I'd mention it:
Some info found here-
http://www.soundown.com/S...03%20PDFs/Handbook.pdf