Originally Posted by ShawnQ
I assume this is because the car is running so rich that it bogs it down. More air from a properly functioning supercharger requires more fuel. If that S/C suddenly stops working and the car is still dumping fuel, it will bog and run poorly with low power.
Close. The ECU goes into a limp mode when the supercharger overheats, limiting engine spark advance and disabling the supercharger clutch until the supercharger cools back down to acceptable levels. Being fuel-injected and ECU controlled, there is no possible way the vehicle will run overly rich if it doesn't have to. Modern cars will run stoichiometric at cruise, rich in acceleration, and lean in deceleration.