The Cessna 120-140 Association Forum

Looking at the G100UL STC, seems like our planes will cost $175. Anyone bought the STC?

https://www.g100ul.com/

What's the availability and cost of G100UL fuel compared to 100LL? I for one haven't seen any FBO's or airports in NW Florida advertising it.

We have Swift fuel UL94 here at KUSE, Fulton county OH.
They charge $1 a gallon more for it but I don't care.
That is all that I have used on my C-140 and the plugs are perfectly clean.
Runs great.
I am very happy.

Rick

I read, when available, it will be about 80 cents more per gallon... but the upside is a cleaner engine (combustion), and i can stop using TCP in my fuel to scavage the lead out.

i am of the opinion that we do not need to buy the STC since our TCDS states explicitly 73 min. octane aviation gasoline for my little stock engine - re: G100UL is 100 octane which exceeds the requirement. I do not plan on purchasing the STC for either of my airplanes.

rominoff wrote: ↑Sat Jan 14, 2023 5:16 pm i am of the opinion that we do not need to buy the STC since our TCDS states explicitly 73 min. octane aviation gasoline for my little stock engine - re: G100UL is 100 octane which exceeds the requirement. I do not plan on purchasing the STC for either of my airplanes.

Not that I'm an authority on it, but that's my interpretation of our fuel limitations as well. The C85-12 TCDS (E-233) also specifies minimum grade 73 octane aviation gasoline. I haven't looked to see what some of the STC'd engine replacements might have for limitations there, but it's probably worth checking to make sure Lycoming didn't specify something more stringent if someone has an O-235 or O-290 installed.