An octane rating is a system by which a fuel is rated to resist knocking and detonation in an engine.
A high compression engine compresses the air-fuel mix, raising the temperature more than a low compression engine…high-temperature is what causes K&D.
Pre-pressurizing the air-fuel ratio with a turbo or blower also raises the intake’s temperature.
An intercooler…a heat exchanger used to cool the intake charge…
can alleviate the problem a bit.
If we could design an ideal intercooler, one that could reduce the intake charge to at or even below ambient temperature, could we still run the boosted engine with a lower octane fuel as if it were an unboosted engine?