Higher compression yields better fuel efficiency and power. But the concomitant higher compression produces higher temperatures pushing the fuel air mixture pas

Higher compression yields better fuel efficiency and power. But the concomitant higher compression produces higher temperatures pushing the fuel air mixture past the flash point. Aircraft engines during takeoff commonly increase mixture to cool things down at the cost of unconsumed fuel. Water-methanol injection was also used in late high power piston engines during takeoff and even in early turbine engines such as the Dart in the Viscount. In the mid '70s I bought a Renault 5. After leaving the dealer I read the owner manual and discovered that it required premium gasoline. A year or two later, premium was displaced by unleaded and I had a knock problem. Being a pilot I found that a couple gallons of 100 octane aviation fuel mixed with a tank of regular fixed the knock problem. Long trips were managed from airport to airport and a carried an Explosafe™ fuel container for when an airport was not in reach. Aviation octane went up to 130,but was phased out when the airlines dropped their piston fleets. 130 octane was a major factor in the Allies winning WWII.