Ok, i actually know a little something about this cause i researched the shit outta it, so here goes

You normally run a supercharger and turbo system when you want to run liek a t88 on a 4 cylinder, it takes an insane amount of time (liek 4500 rpms) to spool it, and most turbo engines do not have the engine without the turbo to putt it up quick. So to compensate they add a low boost supercharger. BAsically, hte supercharger initiates the boost and gets the turbo going, there is a valve that is pressure operated and when the pressure that the supercharger is overridden byu the turbo, it closes the valev from the supoercharger rendering it useless now and the turbo taking over full control. It actually worked well on the honda i was looking at that developed the system on honda-tech with a jackson racing and turbo, he gained 80 hp or so ont he bottom end and more on the top end becuase he was able to run a bigger turbo (not a t88 that was just as an example)