Abstract: An add-on feedback control unit is connected to an existing mechanical governor for a turbocharged engine to control fuel flow to the engine in response to engine load and thereby maintain an adjustable low speed droop for the engine. The preload on the governor control spring is determined by a movable stop, the position of which is controlled by a pivotally mounted reset lever. A control arm is connected to the reset lever at a selected position relative to the pivotal axis of the latter. The control unit includes a housing having an interior chamber separated into first and second subchambers by a diaphragm disposed therein. One side of the diaphragm is subjected to the turbocharger boost air pressure of the engine. The control arm includes a shaft connected to the opposite side of the diaphragm and having an outwardly projecting end portion connected to the reset lever at the selected position to provide feedback in response to engine load.