Your statement makes sense if applied to “Drag racing”
No, it applies to any supercharged or turbocharged engines. If they have positive manifold pressure (more air then the engine is naturally trying to pull in) then they can't have negative manifold pressure (vacuum).
IOW: Boost pressure is the opposite of vacuum.
It has nothing to do with transmissions.
So, why do drag racers still shift manually ?
I understand positive manifold pressure as well as the source of vacuum.
Aren’t drag cars supercharged ?
Forced air ?
Turbo charged is slightly different as it works more on the back end vs. the front end like superchargers.
Turbo works best at high rpms while a supercharger is always on.
I don’t think there are many “Turbos” on the drag racing circuit.