Genny Exhaust

olley · 02-14-2006, 10:39 AM

Hi Is there a reason genny exhaust's are not ducted up to roof level? instead of making the coach smell if the winds in the wrong direction.

Olley

olley · 02-14-2006, 10:39 AM

Hi Is there a reason genny exhaust's are not ducted up to roof level? instead of making the coach smell if the winds in the wrong direction.

Olley

Cajun Paul · 02-14-2006, 10:58 AM

Hi Olley

I don't know why the manufacturers don't take care of this. I've seen after-market devices you can purchase that ducts the exhaust up to the top of the RV, but you have to put it up and take it down everytime you move the RV. I have also seen posts about this on this website concerning a do-it-yourself fix:

Purchase a length of flexable metal conduit at Lowes, Home Depot, or your favorite supplier. The inside diameter of the conduit should be a little larger than the outside diameter of your exhaust pipe. Cut a slit in the conduit length-ways, about 2 inches long, on one end. Slip this end of the conduit over your exhaust pipe and clamp tightly with two hose clamps. Run the conduit up along your roof access ladder with a goose neck bend at the top to prevent water from entering. Clamp the conduit to your ladder every foot or so. This should work just fine, but be carefull climbing the ladder while the conduit is hot.

This particular project is on my list of things to do.

If you try this before I do, post your results. I'd like to know how it turns out.

paul

edgray · 02-14-2006, 01:10 PM

I can only tell you that the genset factory reps put on a seminar at an FMCA convention I attended, and ALL of them said they could NOT recommend the practice of extending your genset's exhaust. Their concern is increased back pressure, and how it MIGHT affect the load on the motor.

CAJUN PAUL: I would think that any extension "a little larger" than the tailpipe which is "tightly clamped" directly to the tailpipe would be a most restrictive design. The aftermarket products I've seen use a much larger pipe, which allows a "genturi" effect which sucks in extra outside air and flows straight up from the tailpipe. This would seem to create little additional back pressure, but the factory reps WOULD NOT endorse ANY type or design of exhaust extension, no matter how hard those of us in attendance pushed for them to say OK. ED

**RV Wizard** · 02-14-2006, 10:50 PM

To answer one of your questions, Blue Bird did and may still exhaust the generator up through the roof. This design incorporates the length of exhaust and they size it accordingly. They do the same on the engine exhaust.
The Genturi design will not hurt the generator as has been stated; the opening at the bottom of a larger pipe does great a venturi effect.

Cajun Paul · 02-15-2006, 04:21 AM

Wow!
I guess I'll have to investigate more before doing anything.
Thanks for the info, Ed.

**Gary RVRoamer** · 02-15-2006, 06:42 AM

I'm uimpressed with the factory's back pressure argument - that dinky little pipe the motorhome manufactureres put on is already creating back-pressure. But maybe that's why they worry about even more lengths of pipe???

At any rate, extend the fixed pipe with flex tubing that is larger than the existing pipe and leave an opening where it attaches to the pipe. That opening lets cooling air flow in and pretty much eliminates and significant back pressure on the fixed pipe itself.

If you want, you can add a fixed chrome exhaust to the side of yur ladder but only couple it to the exhaust pipe when needed. Use a flex tube, e.g. the rubber ones used in auto shops, to couple the two when needed.

olley · 02-16-2006, 08:51 AM

Thanks guys, now that the question of back pressure has been mentioned, I will use a bigger bore pipe, maybe 2-3" I favour fitting it up the back wall of the coach not on the ladder, all I have to do now is source some pipe and stand off clips.

From previous comments on here, you seem to be able to go to your local store and buy enough gear to build the golden gate bridge

here in britain its a bit more difficult

Olley

charliez · 02-16-2006, 09:23 AM

Also be aware, galvanized conduit or galvanized anything is not intended for exaust pipe. When the galvanizing burns, it creates a toxic gas. I'm thinking sianide (sp?). If your going to do this, get real muffler pipe.

And if you run it inside a wall. make sure it's doubled wall pipe. A hot pipe will leave you with a possible fire inside your coach walls. Not a good thing.

olley · 02-17-2006, 02:10 AM

Hi charliez no I am not intending to run it inside a wall, I think the coach builders could have done that, it would have looked very neat.

I am going to fix it to the rear of the coach with "stand off" pipe clips.

Olley

NeilV · 02-17-2006, 02:23 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by olley:
Hi charliez no I am not intending to run it inside a wall, I think the coach builders could have done that, it would have looked very neat.

I am going to fix it to the rear of the coach with "stand off" pipe clips.

Olley </div></BLOCKQUOTE>

Some Coast Guard rescue ships are made that way with the exhaust pipes running quite a ways under the decks to get them to the back of the boat and even with the high grade stainless steel insulated pipes they still have to replace it all at great cost on a regular schedule.

You may want to consider a stainless steel exhaust stack/snorkel from a big rig junkyard.

Regards,

Neil