Abstract: A supercharger assembly includes a centrifugal blower for delivering pressurized air to an engine air manifold of an engine; a variable transmission for driving the blower; a motor for adjusting a gear ratio of the variable transmission; and a control system for controlling operation of the motor to provide user selectable and/or programmable levels of supercharger boost. The control system may include a user input device for selecting a performance level of the supercharger assembly; at least one engine sensor for sensing an operating parameter of the engine; at least one environmental sensor for sensing a characteristic of the inlet air; and a programmable controller for controlling operation of the motor in accordance with the user selected performance level and outputs of the engine sensor and the environmental sensor.