Converting a Generator to Propane

[JayArr]

I followed all the examples I could find for air flow and mass loaded vinyl but in the end I think my big error was that my box was too small. It barely fits over the genny and so there wasn't enough volume of air around the genny to cool it. The ratio of air space to genny is probably 70-30 under there and that's just not enough. I could add more fans and more ports but that solves thermal issues at the expense of noise. There isn't any more room on the tongue to make it any bigger.

One simple idea I had was a "stack" on the muffler. I currently have the largest muffler Briggs and Stratton make for that motor but it exhausts to the left. I wonder if I could decrease my dB reading if I got a 90 degree elbow and six feet of pipe to send the exhuast UP to above the roof of the trailer?

I see youtubes of these venturi stacks for RVs but I don't know if they are to reduce noise or just to get rid of the exhaust so it doesn't leak back into the RV.

 

[Lou Schneider]

I see youtubes of these venturi stacks for RVs but I don't know if they are to reduce noise or just to get rid of the exhaust so it doesn't leak back into the RV.

Both, though their primary purpose is getting the exhaust above the trailer. The venturi stacks work by sucking cool air into the bottom of the stack and letting it propagate upwards with the engine exhaust. This reduces the velocity of the exhaust in the stack, smoothing out the airflow and reducing the exhaust noise a bit.

 

[JayArr]

Maybe I should go the other way, more like an automobile, use some flex pipe to route the exhaust down and under the trailer to a muffler mounted below aimed down at the earth.

 

[Ex-Calif]

More muffler would also rob HP but not a huge consideration. It would also add back pressure and retain more heat under the box.

The basic problem is cooling airflow and the only way to fix that given the box size constraints is to open the inlet and exhaust sides of the box more (perforations e.g) and increase airflow (bigger fan(s)). Muffler might help but the more you open the box up the more mechanical noise that will escape the box.

You could duct the airflow exhaust under the trailer if you have ground clearance, or as you suggest duct the airflow exhaust up the front of the trailer. This would give you a permanent airflow exhaust run and the air/noise that came out would be ducted skyward.

 

[Lou Schneider]

Maybe I should go the other way, more like an automobile, use some flex pipe to route the exhaust down and under the trailer to a muffler mounted below aimed down at the earth.

That won't solve the problem of CO seeping into the trailer. Hot air rises.