yeah, as I mentioned I looked at a tractor muffler thinking it would have done better than my resonator. I recon as long as the muffler is intended for an engine at least as big it's not going to cause any significant increase in back pressure. Use common sense I think.... but of course the canned answer from onan would be don't.
I'll add this....if my generator was mounted in the rear, someplace where something like this would make sense....In a heartbeat I would do a permanently installed "genturi"....complete with secondary inline muffler before it, similar to the resonator install I did.
The only reason I wouldn't be too interested in just routing the tailpipe up there would be that it would get hot....
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