Probably a real dumb question but ....
At any compression over 10:1 the pressure the turbo puts out has to be very limited. 13:1 requires for street use with a carb and without computer control requires 100%+ octane fuel, adding more compression via a turbo requires more octain and ignition control. I run a supercharger on my slant six with with a boost referenced fuel pressure regulator, and a pressure referenced ignition control modual, at 8.5 compression I still run 94 to 100 octain depending on the boost I want.
At any compression over 10:1 the pressure the turbo puts out has to be very limited. 13:1 requires for street use with a carb and without computer control requires 100%+ octane fuel, adding more compression via a turbo requires more octain and ignition control. I run a supercharger on my slant six with with a boost referenced fuel pressure regulator, and a pressure referenced ignition control modual, at 8.5 compression I still run 94 to 100 octain depending on the boost I want.