,,,Ok everybody,,,I'll throw in my 2 cents worth!!,,,LOL,,,I have been flying avgas in my engines since the late 70's,,,before there was an IMAA,,,By the way,,I'm #120,, the main reasons,,,better fuel quality,,,longer lasting,,,(avgas will remain "fresh" for 3 years),,don't have to de-fuel after each flight,,, a full tank lasts longer,,,I can't honestly tell if there's more power,,,but the throttle response is much better,,,in other words,,the carbs we use on ALL our chain saw,,and chop saw type engines,,,(let's face it guy's,,,doesn't matter WHAT anybody say's,,,that's where they come from,,sure,,some machine special crankcases,,and that's good,,,but ask yourself,,,where do they get the jug and crank assembly's??) are either walbro or tilotson, and I've seen a few zama's,,,they where designed to hold the engine at idle,,,and transition to full power,,,no mid range,,,but we're fortunate that they do!!,,, you might hear of the term,,"flat spot",,refering to a point somewhere between idle and full power,,,on the control,,I've found out ,,with avgas,,it's greatly deminished,,,better linearity on the throttle stick,,, As when doing any fuel change,,,you reajust the needle valve. Yes you have to richen it.,,I have seen guy's that are scared to death to touch the needle valve!! I ALWAY'S make sure I can make ajustments,,, WHILE the engine is running in the SAME configuration as it will fly!!,,,meaning with the cowl and spinner on,,,it DOES make a difference!!,,,Car gas is junk.,,,Plain and simple.,,,Stop and think about it,,,modern day cars all have computer controled engines that constantly are ajusting the mixture through the fuel injection,,,sensors for exhaust,,,pvc valves,,electronic igntion ajustments (timing),,they can run trash and you'd never know!! It's said that car gas is supposed to last a month??,,,my expereince say's 3 weeks,,,if your lucky!! Here in Ohio,,we don't have a fuel quality standard,,,I won't pursue that,,,,anyway,,,I'll stop rambling,,,it's just my opinion,,,