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To me this reads as the higher compression resulting from better fuels means actually less heat due to less fuel being used to create the detonation and overall greater efficiency. So it would seem that higher performance fuel then means that the same engine properly tuned for greater compression would result in greater power without the need for the engine to be altered in its basic construction, i.e. the DB601E using C3 fuel would achieve 1500 hp (roughly) if properly tuned and compressed without any cooling system changes.A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air-fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, and therefore the energy wasted to the atmosphere.
I always believed that higher octane rated fuel, with lead added to the fuel, actually slowed the burn rate of the fuel. Fuel without lead, overall delivers less power because the ignition is not sustained and much energy is lost in the more rapid reaction of the fuel to ignition. . what us british types refer to as "standard" fuel actually ignites more or less instantaneously, whereas a slower burning fuel, with an ignition inhibitor added burns longer, allowing the full effects of the long stroke of the pistion to be utiilised.
i dont know about heating effects, but i do know if you run standard fuel in an engine tuned for super grade fuel, you will get a ping in the engine, and likley valve or pistion damage. Invariably running the wrong fuel will raise the operating temperature of the engine because it is impossible to get the ignition timing optimised
Well, that article does not disprove my claim: The best fuel economy is obtained at peak EGT. And the problems listed speak volumes of the crappity of Lycocraps and Contishits pretending to be aero engines while being fishnet weights.
There were numerous better GA engines in existence, like Argus, Hirth, Kinner, Jacobs, DH Gipsy. The latter was cleared to 1500 hrs TBO in 1944 in wartime conditions with wartime oils and mostly used fuels well below 100 octane with competitive sfc. My favourite would be a 5- to 7-cylinder radial with turbocharging, liquid-cooling, direct injection and sleeve valves.