Is it possible that since the person in this story got this fuel from a military base, it might not even be gasoline but maybe jet fuel - such as JP-8 ?
As mentioned, anti knock additives suppress knock (detonation) by raising the autoignition temperature of gasoline - i.e. the air fuel mixture in the combustion chamber can withstand higher temperatures/pressures before it ignites on its own. The higher the level of suppression, the higher the octane rating.
Since fuels like diesel or JP-8 are not designed for (SI) spark ignition engines, the prevention of autoignition is not really a concern (the engines that use these fuels actually depend on autoignition, right?) Therefore, the octane rating of these fuels is extremely low. I found one site that put the octane rating of JP-8 at 15. It did not specify if this was RON or MON, but either way the point is moot, as the octane rating is essentially in the basement.
If a fuel like JP-8 was used in a conventional SI engine, I could see how the engine could experience severe levels of detonation. If run for any length of time this could lead to internal overheating and permanent damage.
WRT to 100LL, if someone can explain to me exactly how it will run perfectly fine in an engine with 10:1 CR and "destroy" an engine with 7:1 CR, I would really like to understand the specifics of how such a thing can happen.
As also mentioned previously in this thread, many have run 100LL in low compression engines without experiencing any damage. Due to its lower vapor pressure, I can see how its use could lead to cold weather starting or drivability issues, but I have a hard time believing that it will cause catastrophic engine damage.
Best Regards....
