Lycoming Engine

Compression ratio and 100LL?

Why do Lycoming's O-360 related engines use 100ll when they only have compression ratios of 8.6 or less? A regular car engine, such as the jeep 4.7ho have compression ratios of 9.7:1 and can use 87 without ill effects.
There are some STC's out there that increase the stroke, which increases displacement and compression up to 9.9:1, and they still use 100ll, so what is with the low compression models?
Is it something to do with standardization with the turbo models?

they are air cooled engines that produce hot spots which can cause detonation if the octane is not high enough to prolong the burning process of combustion..

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