I know Av gas is made differently then auto gas (formulated for longer shelf life ~ airplanes do sit for extended periods ~ and have to withstand higher altitudes & extreme temperatures) something auto gas
is not taken into account for....it's specific gravity is much less than that of auto gas....for it's volume there is less mass, less dense ~ a quicker burn (more lean) for a given injector pulse & would damage valves
& melt pistons ....definitely a longer pulse width for more complete burn....my Arizona speed & marine efi's are of a mid 90's would the ecm need to be tuned?....

Without tuning the ecm, howwould you tell it to change the way it injects fuel???

Fuel pressure. I'm not saying it's the right way or will even work. Depends how far the a/f is off and if the changes needed are linear. That is the crude way that has been done since efi came out.

I personally would get the ecu retuned.

I reached out AS&M and they said first if I could get the #'s on the injectors for identification and start from there and proceed with a tune...

If your reason for using it is longevity ( mine is layed for 9+ months and is just fine so I don`t get the reasoning but okay ) wouldn`t it just be safer and easier to suck the gas out and put in fresh when you`re ready to go? You`re going to change your entire tune to used AV gas only available at airports? makes ZERO sense.

OK... so this is a 12 year old thread. I used AvGas in my Top Gun with N/A 800's from '08 until I sold it in '13 with no issues. We couldn't get non-ethanol fuel in MD and it was a great alternative! I also used it in my lawn mower, John Deere Gator, weed whacker and my wife's Honda Ruckus. Great smell, never went bad and never had to rebuild any carburetors!

What about fuel mileage? (Joking) Ok sorry couldn’t resist.

Carbureted or efi's?.....did you have to run slightly larger jets in the carb?......my injectors would need a slightly longer pulse width for Av gas

Longevity definitely....and availability is close to me.....when you pull an injector and see what gummed up garbage runs through them with ethanol gas yea, I'll definitely tune for Av

Carbureted, No jet changes, no issues....