Abstract: A retrofit turbocharger booster (10) for a solenoid (19) controlled turbocharger (20) having a wastegate (28) which opens and closes in response to a pulse train generated by an engine control module (44). The turbocharger booster (10) includes first and second connectors (12) and (13) that are connected by first and second wires (15) and (16) to a diode (18) between the engine control module (44) and the solenoid (19). The diode (18) modifies the pulse train of the engine control module (44) extending the "on" pulses of the pulse train. The diode (18) is reverse biased relative to the engine control module (44) pulse train.