Genset exhaust

[Paladin]

 A couple of questions: Is there any benefit to running the exhaust from the front to the rear? My thinking, or wondering is that I could run it to the rear where the bus exhaust is anyway, I could make an adapter such as others have made to turn the exhaust upward while parked to put the exit up higher where the wind could catch it and disperse it and I guess the sound would be above as well though I just wonder how much there would be. Sure, admittedly this could be done from the front too though.
Another thought is that running down that length the exhaust pulses would pretty much smooth out and supposedly lower the noise.

Also, is there anything to be gained or lost by running two mufflers over the length? I just don't see that my little 6500 genset really makes enough noise to benefit from that second muffler nor would it suffer any appreciable back pressure which I also doubt would really be an issue for that little motor.

The obvious thought is to create a box that would quiet as much mechanical noise as possible and also silence the exhaust note as much as possible too in order to be a good neighbor.   

Lastly, I know that people have placed their genset in their MCI, in the condenser bay, presumable on sliders. Does anyone have any first hand knowledge of being able to put an Onan 6500 commercial in there on rails without too many mods?
Since my (failed) back surgery I don't have the luxury of wrestling the heavy genset in and out trying to see if it will fit only to find out that it won't. If I can't get the generator in there I'll probably just put my battery bank in there.

[Oonrahnjay]

A couple of questions: Is there any benefit to running the exhaust from the front to the rear?  (snip)  

    Dave, there are "benefits" as you've noted but the question is whether it's enough of a benefit versus what you need.  If you can place your gen where the exhaust won't be near the door or windows or near where you plan to be around the bus (planning an awning with lawn chairs and BBQ grill near the side of your bus?), then there won't be much gained by moving the exhaust outlet.  On the other hand, based upon how you intend to use the bus, it may be worth the time, effort, expense and weight of running an exhaust to the rear/top of the bus.  It's kind of up to you.  On my bus, there's virtually no exhaust noise 5 feet from the exhaust outlet but the outlet is in kind of a bad place so I'm planning to put a 1 1/2" flexible pipe (the kind that garages use to stick onto your car exhaust pipe in the winter when the bay door is closed) on the end of the metal pipe and run it up the side of my bus.  But that is more for heat and smell than noise, although it will reduce noise a bit, too.

Also, is there anything to be gained or lost by running two mufflers over the length? I just don't see that my little 6500 genset really makes enough noise to benefit from that second muffler nor would it suffer any appreciable back pressure which I also doubt would really be an issue for that little motor.
The obvious thought is to create a box that would quiet as much mechanical noise as possible and also silence the exhaust note as much as possible too in order to be a good neighbor.  

When you say "commercial", do you mean an air-cooled generator?  If so, there's not much you can do by adding a muffler -- there's so much mechanical and intake noise that having a perfect exhaust muffler won't make much difference -- either to you inside the bus, when you're near it on the outside, or to neighbors in the vicinity.  Having said that, if exhaust noise if the big part of your setup, maybe an extra muffler would help.  Or maybe a better single muffler.  Having the long exhaust pipe will help some, too, if you decide you need to go that way.
You may be able to make a difference in the nearby noise level of your gennie by doing a sound box, making sure all the mounts are flexible or rubber cushion, etc.  But air cooled is hard because the air transmits the sound and you have to have big intakes for cooling air to go in and big outlet vents for the heated air to go out.  All these let a lot of sound escape as the air moves through them.  (Although if your setup allows it, ducting and baffling may help but don't depend on it helping a lot.)
So, I guess the only advice is that if you can "do all the right things" and get the gennie quiet, then you will need a good exhaust muffler.  But if you have a reasonably efficient muffler now, you're probably not going to have any/much need for a second one.  If the one you have isn't very good, changing to a better one (single) may or may not be better than adding one.

(Sorry can't help with info on your bay or mounting locations.  Sorry to hear about your back, I had a big, bad back injury years ago and count my blessings that it healed reasonably well.)

[Lin]

I use one of those flex hoses to route the exhaust to the roof sometimes.  It seemed to make a noticeable noise difference on the Onan I had on the last bus, but it does not seem to effect the noise much on my air cooled Kohler.

[oldmansax]

My old MC7 had an Onan Marquis 6.5 air cooled gasoline generator in the condenser bay. It was quiet a mouse with no extraordinary insulation & the stock muffler. I had a vertical exhaust that attached to the side of the bus if I was camping long term. I really didn't need it much. Mine was not on a slide & exhausted through the floor.

TOM

[wagwar]

I have a side outlet near the rear of the bus and use a "Genturi" exhaust system to vent the exhaust at the roof line when camping. Camping World sells them. They are light, easy to put up and come with their own carry bag. This gives me the flexibility I like to vent it to the side or up to the roof as the situation warrants.

[Oonrahnjay]

I have a side outlet near the rear of the bus and use a "Genturi" exhaust system to vent the exhaust at the roof line when camping. Camping World sells them. They are light, easy to put up and come with their own carry bag. This gives me the flexibility I like to vent it to the side or up to the roof as the situation warrants.

    Thanks, Jim -- I'll look at that.