Don Tuite wrote:

1. If regular mogas is 80/87, like it says on the pump, and you take
out the octane booster (alcohol), what is the octane rating of the
remaining gas?

It depends on the ethanol blend. Ethanol itself is about 100 octane.
When mixed with gasoline at a ratio of 90:10, gasoline to ethanol, (E10)
it raises the octane of the mixture by about 2 to 3 octane points,
compared to the base gasoline.

2. How do mid-grade and high-test achieve their octane ratings? Do
they just add more alcohol?

Different refining of the gasoline as a base, then the addition of
ethanol to boost it the final amount.

What I'm asking is, if your engine is rated for 80-octane, and you
reduce the octane rating below that by taking out the alcohol, is that
a good idea?

No. You should start with a higher octane rating mixture before removing
the ethanol.

3. What is *in* that non-alcohol gas in Iowa now that boosts its
octane? TEL? MTBE? Nitroglycerine?

Iowa hasn't used MTBE for many years. Ethanol was its replacement, and
pretty well any automobile engine is allowed to use a mixture of up to 10
percent ethanol.