The present invention provides a flexible fuel, spark ignition, variable boost, supercharged internal combustion engine. A variable speed drive assembly connects the engine output to a supercharger. The engine includes a fuel sensor which provides a signal to an engine controller which determines the type of fuel. The engine controller also receives signals from a mass air flow sensor, a manifold air pressure sensor, a crank angle sensor, a camshaft angle sensor, an oxygen sensor in the exhaust stream and a transmission controller. The engine controller provides control signals to an ignition module, to a fuel injection system, to an electronic throttle control, to a supercharger drive controller and to the transmission controller.