[iowagold]

The 2" exhaust pipe does not extend into the Genturi as it is air gapped. The upper part of the Genturi is 4" pipe that is about 10' tall. So, water would simply run out onto the ground. Imagine in the photo for post #15 that the Genturi was leaned to the right. Water would come down the 4" pipe and run out harmlessly. It would look something like this...

View attachment 16326

I sounds as if the way you are planning to install your exhaust is quite different from the Genturi, so comparing it to the Genturi is not really applicable.

i would still do some sort of water trap at the bottom run exit of the gen shed.
condensate from run and basic moisture could run back in on the small one to 2 inch exhaust from the gen set.
maybe a silicone duck bill setup or a deep J trap with water in the trap.

any moisture at the exhaust is a bad day in the making for the next run up.
thinking engine internal rust.

 

[iowagold]

use triple wall stainless steel setup like they do for wood stoves.
or double wall like they use for NG and LP water heater setups.
they deal with the heat issue,
and there is through wall solutions.
PM if you need links for brands and sources.
it is not low cost but it is a real good setup that will last for years.