Generator exhaust

[Tim Walsdorf]

I have an 8kw Kubota diesal generator in my front drivers side bay,is there any limitations on length for exhaust pipe?and should the muffler be close to the generator or close to the end of the run?
I want to  run the exhaust either to the front or the back of the bus for normal use and make a portable bracket to run up to the top of bus in certain situations.

[Nick Badame Refrig/ACC]

Hi Tim,

No, Not a problem at all. But, as with any long run of pipe you should increase the diameter of the pipe to compensate the added

legenth. Now, I would determine how many "turns" you plan to design in the exhaust because the more 90's, the more restriction you create.

Maybe someone here knows a formula to use as rule of thumb. And I would concider running it to the rear as you may want to operate it

while driving at times.

Good Luck
Nick-

[John Z]

I agree with not wanting the exhaust at the front. And i don't know if there would be problems with moving the muffler, but i have only seen them mounted close to the generator.

When i bought my buy the exhaust was run to the back axle. I did not like that, because it is too close to the bedroom window which opens.

When i replaced the muffler i had the exhaust shortened up to exit about half way back under the window where the bathroom is. This window is sealed and paneled over, so it made more sense to me to put the noise there.

[Utahclaimjumper]

Hi Tim, I have a 12.5 KW Perkins diesel gen. and I have the exhaust all the way to the rear of my 06 with the muffler about 5 ft. from the end ahead of the bus engine. Works perfectly, but high centering is an issue, I've munched the flex pipe connector from the engine to the runner twice in nine years.>>>Dan

[HighTechRedneck]

Just curious, has anyone run the generator exhaust through the roof to reduce the ground level fumes and noise?  Aside from another hole in the roof and the sound/heat insulated space for the pipe, would there be any downsides to doing that?  It seems like a good plan but I haven't noticed anyone mention doing it so I am wondering if I am overlooking a pitfall.

[Prather]

It is best to keep the muffler as close to the gen as possible, if the muffler is too far away you get moisture buildup in the muffler and the exhaust heat will not dry it out. Therefore the life of the muffler is decreased.

Prather

[Dreamscape]

We have an Onan 12.5 kw. It is mounted in the front bay drivers side. Exhausting to muffler that is mounted in the rear of the wheel well, running under the side, coming out to just in front of the driver axle. I did not install the unit, it works OK though. Pipe size is about 2 inch, I think.

Good Luck,

Happy Trails,

Paul

Dreamscape

[DavidInWilmNC]

Just curious, has anyone run the generator exhaust through the roof to reduce the ground level fumes and noise?  Aside from another hole in the roof and the sound/heat insulated space for the pipe, would there be any downsides to doing that?  It seems like a good plan but I haven't noticed anyone mention doing it so I am wondering if I am overlooking a pitfall.

I believe Christy Hicks and her husband ran their exhaust through the roof.  She's a member of this board, so maybe she can give you some info.

David

[Tom Y]

Redneck, I looked at one thru the roof. Is all they did was put one pipe inside another.  The outer pipe is open from below to above so the air warms and escapes. The gen exhaust is cut in and must go up. No insulation between the two.  Tom Y

[kyle4501]

If you run the exhaust up thru the roof, there are more issues to deal with.
- exhaust temps can get very hot, so you need to address this, most common is double wall pipe for the exhaust. You really don't want to take any chances here. Waking up to a fire is not a good way to start your day.

- exhaust gasses are toxic, so you want to be real sure the chase is sealed very well to keep the gases out of the coach. I'm planing on sealing a pipe from the gen compartment thru the roof & run the double walled exhaust pipe thru that. Waking up dead tends to have a negative impact on your productivity.

-water leaks from another hole in the roof, I guess I'll deal with it as best I can.

Personally, I don't like any exhaust at ground level, stinks up the campsite more than my attempts at cooking. 
If I can figgure out a good way that looks good too, I'll run the engine exhaust thru the roof too.

[pipes]

My generator will be mounted in the front bay.... I installed a 4 inch square steel tube up thru the aft end of the left front wheel well
(05 Eagle) up thru the floor and roof., close to the side wall. I made two aluminum flanges one inside roof one on top, sealed both sides with butyl rubber caulking and riveted.Then install 1.1/2" exhaust pipe inside that. thru the wheel well bulkhead and up..

My thinking is the 4 inch tube is large enough to draw the ambient air from the wheel well to cool the the inside pipe .The 4 inch tube in the living area is directly in front of the 14 foot slideout so it wont be be in the way.
                                                        .Due to rounded roof the exhaust pipe will not be higher than the roof top.


OOOPS That 4" tube is 3" !!!

[Tony LEE]

Another thing to consider is the proximity of roof hatches that could allow exhaust fumes inside.

[akbusguy2000]

One of the major concerns I had when installing an 8KW generator was the exhaust system connections when the generator is mounted on a slideout and the exhaust system is fixed to the coach body.  What sort of marrying gadget do you put between the two?  I couldn't find anything that would work satisfactorily, since the generator is mounted lengthiwise in the old condenser compartment, and the exhaust manifold is on the outer side of the unit (GM 4106).  I could have mounted it in the opposite direction, but all of the service points are on the wrong side for that - oil check, pump, controls, etc.

I originally tried an 8-ft flexible exhaust pipe that ran down through the floor of the slide-out and to a muffler attached to the underside of the body.  But it was stolen by an inconsiderate railroad crossing.  I ended up with a muffler and short exhaust pipe mounted on the slide mechanism between the generator and the outside screened door.  The exhaust pipe comes straight out, and terminates at a hole I cut in the screen.  It works well while under way and I have an exhaust extention that I add while parked -- which goes straight up the side of the coach.   

[boogiethecat]

TomY has the right idea.  I've got my genset exhaust running thru the roof, happy as can be.  I used a piece of 1-1/2" EMT conduit tubing for the exhaust and it runs centered through a piece of 3"EMT that is open to both the top and bottom.    My roof is steel so I simply welded the 3" to it for no leaks.  Any rain that gets in just runs to thr ground and never causes any problems.  Three  screws on the top and three on the bottom center and hold the inner pipe .
Convection between the two pipes cools the 3" to the point that you can lay your hand on it inside the bus without getting burned.  It works well and best of all, the stink and noise all goes straight up.  I got a little weighted automatic cap for the center pipe from Grainger so there's no rain problems there either, and i'm a happy camper~!

[DrivingMissLazy]

My generator exhaust was constructed using a fitting similar to what a Model A car is if you know what that is. The genset was on a pivot that swings out for service. When it swings back in the two parts of the exhaust system mate up in a compression type fitting that provides a perfect seal. A lock screw maintains the genset in position and pressure between the two exhaust components.
Richard