Rusty,

I think the pipe you purchased will work. I got the thin wall PVC at Lowes.

Bill G

I checked three Lowe's as well as five contractors' and plumbing supply places - none had the 3" thinwall, although 4" was plentiful.

The Selkirk flue has, of course, the most important feature, in that it can be painted to match the coach, and the paint will stick....

Liberally stealing from Bill G's design, I've about finished my clone of the BillGenturi clone. Rather than use steel, I used 3/4"x1/8" aluminum (because that's what I had). I made the venturi itself detachable from the elbow; the elbow itself attaches to the genset tailpipe, but when not in use a 6" stub goes onto the connector, which is now permanently attached. The 3" Selkirk gas vent pipe fits nicely into a 3" PVC coupling.

I'll post photos when finished.

BTW, I installed a new muffler (slightly oversized), and an Onan resonator (about $60), and the reduction in, and alteration of, the noise is remarkable (the genturi hasn't been tested yet, although I suspect it'll make little difference).

Rusty,

Sounds like you have improved on the design. I'll be looking forward to seeing your pictures.

My genny is powered by a four cylinder Kubota diesel and I would really like to quiet it down. I have wondered if a different muffler would make a difference.

Good luch on completing you project.

I'd guess that, with contemporary emphases on sound "pollution", that Kubota has improved mufflers available.

I have a really good RV dealer locally, and they suggested the resonator, and I'm sure that helps.

Diesels of course are more susceptible to exhaust back prssure, so I'd be inclined to stick with OEM recommendations.

Off to the workshop to finish the brackets and to paint the pipes...(gonna be very careful about overspray and runs - we know why )

Yes Rusty,

The folks here at BM.com insist on high quality work. Make sure that you take hi-resolution photos so that I can enlarge them and inspect your work .

I emailed Power Tech today and asked if they had any improved mufflers for my engine. I also noticed that for new applications, they offered a sound proof case into which the generator is placed. This is not applicable for me, but quieting the operation of the generator is now on their minds.

Bill G

Here are pix of the nearly-finished ripoff of the BillGenturi. Yet to be done is installing the correct screws and bolts, radiusing the rest of the bracket corners, painting, and applying foam to the inside of the bracket.

A note on vibration - the pipe vibrates slightly, but this isn't transmitted to the coach's skin - absorbed by the suction cups. I intend to line the clamp's side where it contacts the pipe (in a fit of insight, I made the clamp radius large enough to allow for this) with high-density foam.

The pipe fits nicely into the 3" PVC coupling; a 1.25" EMT conduit coupling forms the bottom and the exhaust outlet.

The EMT sweep ell attaches to another 1.25" EMT coupling on the tailpipe (which is permanent). A 5" stub replaces the ell for cruising to get the exhaust beyond the coach side.

This was done to get the rig closer to the coach (see below).

The heart of the matter. The 1.25" coupling has six lands along its length; the top ring between pairs of these was filed flat to provide a base for the straps.

The notches in the lower bars are for clearance with the suction cup housing, since the bracket attaches forward of the front post radius.

The diagonal bracket was added because even with the clamp tight, the pipe would rotate in the PVC coupling. Since at the Nebraska Star Party and the Mid-South Star Gaze last year, we had winds above 40 mph, I didn't want this to move.

This is also why I made the assembly closer to the coach (4.5") than Bill G's - less stress on the suction cups in a high wind. I sized the bracket to be mounted higher up for the same reason - less torque moment...

quote:

Originally posted by Bill G:

I emailed Power Tech today and asked if they had any improved mufflers for my engine. I also noticed that for new applications, they offered a sound proof case into which the generator is placed.

Bill G

That is interesting. Is there a link or something where I could learn more?

bill h,

I haven't heard from PowerTech as yet, but here is a link to their website. http://www.powertech-gen.com/

Rusty,

You're genturi is coming alone nicely. I used "S" bends in the stainless strapping on my genturi to absorb the vibration. It works very well. The power of those suction cups is amazing, you'll really like them.

Did you say that you were going to paint the tube as well?

Bill G

I suspect that my Kohler LPG-fueled genset vibrates less than the Kubota (as would be expected) - it's actually quite minimal, such that the foam will absorb it quite handily.

Naturally, I have to paint the bracket and the pipe, based on critiques certain members have received from certain other members about runs and overspray...fortunately, light colors (bright white epoxy) show faults less than darker colors....but I'm not going with 27 hand-rubbed coats of lacquer....

As an aside, the BillGenturi did quiet the engine noise somewhat, so that the main noise comes from the genset compartment. I'm experimenting with a baffle (nothing elaborate - just a shield behind the louvers), and that shows some promise. Basically it's just a sheet of insulation between the louvers and the engine, with plenty of clearance for cooling air. So far, it appears promising, but I think I need to determine a useable size, then order some Accousti-Mat. I may end up just with a bit of Accousti-Mat over the exhaust header, which seems to be where the main noise is coming from.

i have the 86 regency .. enjoying like your re routed exhaust but im running the three cyclinder kubota gen.. thinking of linning the interior walls with fireproof sound absorber .. my gen is located center front between driver and passenger..new owner sept 30th ... 1300 miles already but improvements and repairs necessary .. this is a cool sight n ..

Update - Lowes has the thinwall 3" back in stock - it's "sewer" or "sewer/drain" pipe. Couplings are labelled DWV-SD, as the 3" Sched 40 is bigger due to the sidewall thickness of the pipe.

I got two 10' sections with the belled end for coupling, and so need only one coupling to replace the one on the base...straight stock, followed by the two pieces of belled. 38" long each, they fit into brackets on top of the genset housing.

Per earlier posts in this thread, I replaced the Kohler with a used Honda EV-4010 gaso inside a soundbox, and it's substantially quieter and burns gaso at a rate significantly less (.33 gph, 1/2 load) than the Kohler propane unit (.85 gph, 1/2 load).