Abstract: A flow meter including at least one flow valve used to performance test system compressors is described. The flow meter includes a pressure vessel including at least one exit port. A flow valve is coupled to each vessel exit port, and each flow valve discharges fluid from the vessel at a pre-determined flow rate. The flow valve includes a first end, a second end, and a bore extending therethrough. The bore includes an entrance portion and an exit portion. The bore entrance portion is frusto-conical and curves outwardly from the bore exit portion such that a diameter of the bore entrance portion is variable and larger than a diameter of the bore exit portion.