Abstract: A pneumatically controlled flow booster includes a booster valve plug position sensor that enables control of the flow booster in a feedback loop, for example by a pneumatic valve positioner, thereby providing accurate, high speed, high flow control of both small and large actuator adjustments. Embodiments can accurately control a surge suppression valve over extended valve adjustment ranges and can fully open a surge suppression valve during a trip. The flow booster valve can include a spool and sleeve valve and/or a poppet valve. Embodiments provide bimodal flow boosting, whereby the output flow is less dependent on the valve plug position in a first position range, and more strongly dependent on the valve plug position in a second range.