bought a new-to-me older dp coach - with diesel generator - this summer and parked it in my driveway. fired up the gen and within a few minutes received a txt from my neighbor that even with their doors shut and air conditioner on my gen diesel exhaust was infiltrating their house. ack!

immediately shut down the gen and reviewed what i'd previously read about the genturi, then ordered the unit + the extension (tall coach) and suction cups. genturi + extra parts arrived promptly (as expected), assembled / installed in ~10 minutes and fired the gen up ... seems a bit quieter inside the coach and the exhaust is vented up and away from our driveway and the neighbor's house.

it's a great product and using it is a no-brainer ... storage is made simple and easy-peasy with the (included) storage bag.

Ordered on 7-22-2017 and installed 7-26-2017 in about 5 minutes with the generator running. Should have shut it down and allowed to cool, but it was hot out and I wanted the air conditioning to stay on!
The exhaust fumes had been pooling around the coach for about 2 weeks, so I ordered and installed this on my 2001 Fleetwood Expedition 34n. It is a simple install with only a 9/16" wrench to secure the clamp on the exhaust pipe.
Instead of drilling into the coach to install the mounts, I purchased the suction cup mounts for $11.31 here on Amazon https://www.amazon.com/gp/product/B00PAIMXLQ/ref=oh_aui_detailpage_o00_s02?ie=UTF8&psc=1
I did get a "whiff" of exhaust fumes, so I am going to add the optional extender.
Bottom line, while you could fabricate your own setup, unless you use the right materials and the right air gap for the venturi effect, you won't make a better product and quite possibly could make your situation quite unsafe. These should be included with every RV that has a generator. Camping World has them in store ( at least here they do), you should get it when you buy your RV there.
Update, I've added the 18" extender and now there is not even a whiff of fumes from the generator. It does bump against the coach when I walk inside or there is a light wind. I will add something to work as a standoff for the pipe and that will take care of that.

I do not know why RV manufacturers do not consider the generator exhaust fumes when they design them. In my Class A gas coach the generator exhaust vents in the rear of the coach. MY bedroom window and Basement A.C. are within 5 feet of the exhaust. I took readings on my CO2 detector and when the generator is running the levels are in the unhealthy range in the bedroom (even with the window closed). This product fixed the problem!!! It is a bit of a hassle having to use it, but can save your life!!!
Buy it if you boondock and sleep with the generator running. You will be glad you did.

This will not quiet your generator in any way, shape or form. You would purchase this only to get the exhaust fumes away from your coach or the folks next to you. I like it. I can now keep my windows open while the generator is running. It is easy to install. I purchased another suction cup to hold the extensions to the coach.

This thing is sweet! It's solid as can be. My generator tube was small so the smallest shim needed tightened at first to clamp on to it. If you do this, you'll need a deep well socket

During tightening, i snapped the "u" shapped exhaust bolt. I went down to Auto Zone and picked another up for $2. So watch out for that if you tighten it too hard.

I still have no idea what these 4 pin looking things do? I am going to upload a picture of them. They are not listed in the instruction video.

I feel like 4 screws should have been included. If anyone figures this out, let me know!

All these issues aside, it still gets 4 stars for working as designed. This thing does the job and no fumes are below the vehicle which is what I was going for. Seems sturdy and easily removable when I need it.

Just let me know how to these these pin things? Someone said it was a screw, but it has no threads.

Oh yeah one last thing. The transport bag was missing the flipper to the zipper. I tied a piece of string around it so I can actually use it.