Hello; Years ago I bought an Irvine 40 Diesel around about the time when a cold snap with lots of snow occurred. I wanted to run the engine but couldn't do it outside. I found an old high-start,(a surgical rubber tube about 1/2 inch ID) and a little ice cream bucket half full of floor dry. I clamped the high start onto the muffler and ran it into a garbage can that had the floor dry in. I put a big Taipan prop on it and plumbed up a fuel tank. Then I moved it all near a door so I could put the garbage can outside and run the engine inside.

I fired it up and was amazed at how quiet the engine ran without any exhaust sound. It would idle nearly silently. I learned about tuning a Diesel while running out those first few tanks through. Eventually the heat from the exhaust melted the high start, which made a mess, but I just cut off the melted part and started again.

I don't think you can get away with confining the exhaust gasses in an alcohol engine like you can a diesel, I haven't tried this with a glow engine, but it works great with Diesels.