Yeah! UL94 has been approved since 2015, but there have been numerous hold ups with the FAA for the 100-octane version. Since a lot of the GA fleet requires 100 octane fuel due to higher compression engines, UL94 is of limited use.How common is UL94 down there?
Another company, GAMI, was just given FAA approval for a 100 octane unleaded fuel called G100.
Unleaded avgas is fairly common in the Midwest, but almost impossible to find in California or out West.
The fuel meets FAA specs for avgas, so any engine placarded to run aviation fuel with =< 94 octane rating can use it without an STC. I believe the STCs are for engines that do not meet the specs, but still can run it safely. My 1964 C172 has an O-300D, which is placarded for 80 octane, and happily runs on UL94.Doing some more reading, it seems like you need an STC to run UL94.
Haha yeah. I have had to pick out lead from the bottom plugs many times. Also had several stuck open exhaust valves from lead deposits in the valve guides. I run UL as much as I possibly can now.That TEL is nasty stuff for modern engines! It's nasty enough on engines designed for it. I remember picking lead deposits off a full set of plugs off of a Piper twin when I was in highschool...