A method of controlling an engine includes manipulating a wastegate to maintain the operation of the turbocharger within an optimum operating range. A combustion air bypass valve is manipulated between an open position and a closed position to create a negative pressure differential across a supercharger. The supercharger is sequentially disposed in-line before the turbocharger. The negative pressure differential is converted into a torque by the supercharger and transmitted from the supercharger back to the engine to increase the operating efficiency of the engine.