Octane ratings have been being discussed since the 1920's. In the USA they add RON and MON together and divide by 2 to get the rating posted on the pump. It appears the rest of the world uses RON rating today posted on the pump. I find it fascinating that Octane numbers are provided by testing in CFR engines designed back in the 1920's and 1930's. Back in those days those engine were not equipped with High performance High pressure fuel injection systems, computers and sensors or emission controls PCV, CCV and EGR. Has anyone on this forum done and reading about fuel aeration (Takes place in the fuel tank) or fuel cavitation that takes place in the fuel system and injectors themselves. We have known since the first part of the last century that there is a small amount of dissolved air in gasoline and it varies depending on conditions. A fish it swims in water, a fish it breathes air, Can we see the air? No because it is dissolved. This is a documented fact. My concern knowing this information is I am not so concerned what the octane rating is at the retail gas pump or even in my fuel tank. I want to know what the octane rating is when the gasoline is delivered at the injector. How much does aeration, cavitation and dissolved air reduce the octane number of the fuel?