RE: BCMAEngines
Avgas doesn't smell as bad as regular gas, as you have noted. Avgas stays fresher longer than pump gas. Those are the two good points.
Avgas is considerably more expensive than pump gas and is not readily available as pump gas. Will it help engine performance versus fresh pump gas? No. Can it harm a two or four-stroke model gas engine? Theoretically, it "could" cause damage to a two-stroke engine's piston right at the exhaust port. I've never seen this happen, but I haven't ran many engines on Avgas, so I really have no experience in this area. Personally, I doubt it because of the little time we put on our gas engines in model airplanes. I doubt if you would ever see it. Could Avgas be beneficial to any spark ignition/gas/petrol fueled model engine? I don't know. But if there was an engine that could benefit, it would probably be a four-stroke model engine running an ignition system and a high compression ratio, such as a converted glow Saito 1.50 to 2.20 four-stroke engine. But that is only a guess and even then I don't think it would be a readily apparent benefit.
Ed Cregger