I do not understand why gennys are so loud, even the so-calle quiet ones. My car can make 200HP and is so quiet from idle to 3,000rpm that you have to stand right next to it to know it's running. So why are gennys so loud? I know it's the exhaust as I can momentarily put my hand over it and the sound is almost non-existent. I realize a larger muffler system would make for a larger over all genny, but wouldn't that be worth it for stealth?
To that extent, I put my Honda 2000 on my RV roof and ran it there, comparing the sound to the noise it makes when on the ground. Amazing how quiet it was. Standing next to the RV in my driveway, I could barely tell it was running.
Maybe a good after market product would be an add-on muffler to quiet a genny?
I think I may just strap my genny to the roof and put a lock on it, leaving it there!