Jim Macklin wrote:
It's is like the guy who spent $25,000 on tools to build
furniture for his house, to save 25% on the furniture.
During WWII the Army published flight manuals for fighters
(and bombers) for different grades of fuel, 80/87, 91-96,
100/130 and 115/145 being refined. But some battlefields
did not have supplies of all grades. So you might have a 54
In Hg. MAP with 115/145 and only 40 inches with 100/130.

But what octane do you get from home refined mogas?


Not all grades could be used in all engines. 80/87 was not under any
circumstances allowed in many of the bigger engines. And use of
115/145, as was done after WWII (the Navy even ran its jets on the
stuff up through the middle of the Korean War, limiting range and
coating the tailpipes with a lethal (to ground handlers) gray gunk!)
was tough on the Lycomings and Continentals and the gas engines in ramp
equipment.