You are right Ant. The Turbo is driven by the exhaust gasses, it's something like a turbine driving a centrifugal compressor.
Modern small Turbochargers have almost no turbolag, but if you want serious power a larger Unit is reqired, which unfortunately result in some turbolag. The advantage of the Turbo is the fact that it uses the otherwise wasted energy from the exhaust gasses.
Superchargers come in two versions; centrifugal chargers or the Roots Type charger.
Centrigul chargers ( Used by Engstler, and probably novitec
) also need to be revved like turbo cars to perform. But there's no lag as they are belt driven). They are also small handy units as the turbo. They deliver a smooth increase in power following the engine revs wink .
The Roots type Supercharger, doesn't rely on the centrifugal effect in order to pump air into the engine. It's basically an airpump that compresses the air, even at idle, which means that it delivers low down "grunt" all the time. Meaning an impressive amount of torque. The backdraw to this type of supercharger is that it's larger, heavier and more expensive than the Turbo charger or Centrifugal Supercharger. Plus it consume some Horsepowers ( up to 50 BHP
) when it compresses the air.
All the best
PS. As you might have guessed. I'm in favour of the Roots type. And surprise
; I have bought one. It's sitting on my workbench awaiting me getting a grip, installing it.