ZoomZ

As a user of 100LL in my airplane, and as an Aircraft maintenance dude, I can tell you, the only reason they use 100 LL (Low Lead) is to prevent detonation in LARGER, high compression piston engines.

There used to be two grades 80/87 and 100/130. The slash represented to the left the lean octane rating and rich rating to the right.

The smaller engines could use 80/87 but obviously the higher compression engines needed at least 100.

In WWII planes they needed 130 Octane for supercharged, high altitude flyers so thats what they only made.

Eventually, someone saw that it was too costly and cumbersome to store and maintain two types of aviation gas, so 100LL was born to be used safely ALL types of engines.

Lead was added as the cheapest form of octane boost and made in only one facility in the world, in England.

As we all know ( or should know) Octane rating does not made more HP. It burns at a slower rate or resistant to early ignition to to high cylinder temps, to prevent detonation. Timing can be adjusted, but gains would be minimal. In fact, 87 octane has the same heat energy as 94 octane. Enter Ethanol and Alcohol.

Back to airplanes. A lot of samller piston engine aircraft owners can and do use 94 Octane. Some airports provide that service known as MoGas. Certified aircraft need certification. However, it ALL needs to be Ethanol free.

Since 100LL was the standard, piston aircraft manufacturers, engine and parts manufacturers did not make airplane fuel systems compatible with ethanol. Dont fix whats not broke or Required.

Here we are in 2023 and the mandate for NO Lead gas has pushed the invention of 100UL. Cost more than AvGas and gonna take a long time to set up. Unfortunately, only a couple of manufactures, and only one really shipping out.

So stick to your 93 or 94 octane and deal with Ethanol.

Canada use to have Ethanol free from Chevron 94 octane and Shell 93. Often same or very close to Aviation 100LL. I just stuck with 100LL for the plane. It would have been nickle and dime and a pain in the A$$ to Gerry can. As of 2022, current Canadian govm't mandated Ethanol to up to 10% in all Auto gas.

The Lead is bad for everything. It's poisonous, it fouls Spark plugs (balls of lead), covers the belly with grey soot (like clay) and we can't use synthetic oils because they do not scavenge the Lead blow-by like mineral oil.

Hope that clarify's a few things about 100LL and 100UL.

__________________
“Action without vision is a nightmare.”