Drag racers used nitromethane in the "top fuel" events but they used pure alcohol in some classes. Octane of pure ethanol is about 110. Less heat content but when using turbos or superchargers they can raise compression and pack in more fuel and make up for it. It does burn really clean. Some pit crews have been seriously burned from alcohol fires when they couldn't see the flames.

Have an '02 Lexus that I drive long distances. Supposed to run mid-grade. Ran ethanol-free initially because the engine was not designed to run on 10% alcohol. Then I noticed my mpg go from 28 to 31. Win win. Sheetz usually best source for price/octane. I find this site helpful when traveling:

https://www.pure-gas.org/maps

I now run ethanol-free in vehicles '08 and older. Mine don't get driven often and the ethanol-free with stabilizer will last a year. I have no fuel system issues.

I recommend all gasser coach owners to consider. I certainly wouldn't be running the 87 garbage.

Alot must depend on the car and its engine, had a Cadillac SUV with a 3.6 V6 engine that did not seem to care if it got gasohol or unleaded gas milage was pretty similar. Did not really do a really close study though.

My Mecedes on the other hand is supposed to run on 93 octane or E85, I only put E85 in it a few times and it ran terrible, tried running straight unleaded 87 octane and it pinged badly so I quit that. Now I run 10% gasohol only Shell and it runs pretty good, and saves me over $1.50 from 91 0ctane, 93 octane is not readily available here in Iowa. By the way here in Iowa most 91 octane contains 10% ethanol. Discount stores have it leadfree.

Next spring when ole 71 hits the highway, here in Iowa it will probably get 10% gasohol and elsewhere unleaded if it is less expensive, will try to keep a milage record, am really curious how it will respond to each fuel.

In the old days we used alcohol in race engines because it allowed higher compression (hence more horsepower) and ran cooler, and cleaner. Usage was about twice as much and tuning was at much more advanced on timing. if you ran a comparison test of gasoline and gasohol and adjusted your timing to take advantage of the slower burning (getting the highest and best use of both fuels) your mileage per gallon would be closer to 5% less than pure gas. It is due to the fact that you are tuned for gasoline and using a mixture that wants a different tune is why you are getting a full 10% less miles per gallon. The reason that pure alcohol is not allowed in most race rules is that in case of fire the alcohol burns so clean that the flames cannot be seen by rescue workers.

I add lubricant to our diesel and mostly run non-ethanol in my 86 F150 and 2004 Jeep Wrangler .