Notwithstanding where the exhaust goes, you might look at schedule 80 plastic pipe available in the electrical section at the big box stores, Lowes, etc. You would initially think it plain silly to use plastic pipe for exhaust, but the schedule 80 stuff just doesn't melt, and it's even difficult to bend after you've torched it with a propane torch! Very tough stuff. I used it for an exhaust pipe for my Honda 2000 that I had installed in a box on the back of my previous fifth wheel. Worked great!! And the price is right.