superchargers

Vehicle with supercharged is designed for quick launch at speed up to 100 to

120 km (well my car is anyway). Higher than that you should go with Turbo but then acceleration is a bit slow. So if acceleration (0-60Mph) is important to you than go with Supercharge. I have Supercharged SSEi and my brother has a Volvo high pressure Turbo on his. I find both car perform well on highway as far as pickup but Supercharged will beat car with Turbo from 0-60 Mph (must have similar vehicle specification such as Hp, weight and torque) but after 100 or 120 Km (I don't remember) he will beat me.

Paul

When it is running at too low a speed to cram more air into the engine. Another point is when the supercharger is heating the intake air [due to compression] to such a high temperature that the power gain from more air is lost due to poor combustion efficiency. And the power to drive the supercharger becomes more than the power it adds.

The engine driven chargers tend to be more useful at low rpm since they are driven by the engine thru belts, gears, etc.

Exhaust driven turbochargers tend to be more useful at higher engine rpm...or more specifically when there is a lot of high temperature exhaust available. This can be tuned by using small turbos to turn faster at low speed, then cut in a larger turbo at higher speed and bypass the small one so it doesn't self destruct.

Depends on the specific installation. And whether you blow a hole in a piston by playing with the boost limits.