Avgas, Mogas, Swift and Mix ratios

[Radio Flyer]

Calculating octane after mixing fuels is pretty straightforward. Here's a good link that explains it: https://www.sunocoracefuels.com/tech...ulating-octane

[Shadowrider]

I mix avgas with ethanol 91 and find that running avgas mixed with 91mogas it keeps for long term in my snowmobiles. I run it in a boosted snowmobile and it sits all summer and never have a problem with octane the following year. Doesn’t seem to take much avgas to help stabilize the mogas.

I am currently running 91 ethanol in my plane.😬 If I where not flying often then I will put a tank of avgas in it.