[tabora]

That Genturi design is interesting... I've used similar tech to vent non-electric composting toilets, allowing the wind to create substantial vacuum to keep air flowing through the toilet without having to use a fan. In my case, however, the exhaust stack ends about 1/2 way up inside the outer diffuser tube, about 6 feet above the roof.

What kind of thimble do you plan to use to get the exhaust pipe through the roof? Or will it just be the larger vent tube itself that goes through the roof, with the exhaust terminating inside the building? That sounds like it might indeed have a lot of exhaust leakage inside the building.

 

[tabora]

Yeah, you would have to be careful how you do this.

Having thought more about this, I think that running an extension of the exhaust pipe right up through the roof with a high-temperature 2" flashing thimble and then adding a diffuser tube (piece of stovepipe as shown above) at the top of it would be the safer approach.

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Acquire the ARLINGTON INDUSTRIES, INC 2 in. Conduit Roof Flashing 725-1, aluminum for use on both residential and commercial buildings at The Home Depot

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[tabora]

Looking at those Camco genturi's on RV's I wonder how many gen's have been nuked with a 2' pipe facing upwards towards the rain and the motor not running...

I wondered this the first time I put one of these 14 foot tall venturi stacks in, since my first version had a small 12V fan inside the stack. Surprisingly, virtually no rain actually makes it to the bottom of the stack; the air flow evaporates the tiny amount that makes it into the inner stack before it becomes an issue.

For a 2" exhaust pipe, you could just put one of these on the top. Has worked well on tractor stacks for the last century.

https://www.napaonline.com/en/p/BK_7033502

 

[tabora]

I was planning to explore running the exhaust pipe a little further up the stack and see if the venturi effect is lost

Actually, it would likely be enhanced. Wind moving across the top of the wide pipe will draw air up around the reduced cylinder area between the two pipes at an accelerated rate.

 

[tabora]

Interesting how the Venturi effect still works horizontally, I imagine the wind effect from the moving car can only assist with pushing the air through the Venturi.

Actually, tail pipe tips have little to do with a venturi effect... It's more about resonating and aesthetics.

As we’ve stated, unfortunately, an aftermarket exhaust tip won’t actually do anything to alter the performance of your car; however, it will change a couple of things. Most notably: the sound.​

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Installing a new set of exhaust tips will make your car produce a stronger, more powerful sound. It’s that deep, throaty roar from an engine which petrolheads often appreciate, and installing some exhaust tips will allow you to replicate this sound. Where a new exhaust system will also achieve the same effect, merely installing exhaust tips lets you do this at a much lower price point.​

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New exhaust tips will also upgrade your vehicle’s aesthetic, too. Since your car’s original exhaust pipe is there to perform a function – namely, removing unclean air – it’s unlikely that it looks very appealing. Aftermarket or branded exhaust tips, however, are designed to let your exhaust system achieve the same result, but look good in the process. From chrome and matte finishes to dual-forked and turndown tips, you can style the rear end of vehicle in numerous different ways which passersby can both see and hear.​