A volume booster for an actuator system advantageously includes an adjustable restrictor, such that the exhaust capacity of the device can be adjusted for specific applications. The device comprises a body, a supply path, an exhaust path, and the restrictor. The supply path operates to provide a supply of fluid to boost a stroke time of an actuator in the actuator system, e.g., in an opening direction. The exhaust path operates to accommodate backpressure relief when the actuator system operates the actuator in a closing direction, for example. The restrictor is disposed within the exhaust path and is selectively manipulable between a plurality of positions to define a plurality of distinct exhaust capacities, thereby eliminating any requirement to change the entire volume booster to achieve a different exhaust capacity.