An injection molding apparatus comprising an injection molding machine, a manifold that receives injection fluid from the machine and routes the injection fluid through a flow channel communicating with a gate to a cavity of a mold, characterized in that the apparatus includes: a first actuator and a second actuator, a closure valve pin having a pin axis, the closure valve pin being adapted to be controllably driven upstream and downstream along an axial path of travel through the flow channel such that a distal tip end (124, 124a) of the closure valve pin is driven into and out of a position that closes flow through the gate, the first actuator having a linear or axial driver drivable along a reciprocal path of travel coincident or parallel to the axial path of travel, the closure valve pin being interconnected to the first actuator such that the valve pin is driven along the axial path of travel and reciprocally upstream and downstream into and out of the position that closes flow through the gate, the second actuator comprising a rotor (102, 152) having a rotation axis, the rotor (102, 152) being interconnected to a second valve pin such that the second valve pin is rotatably driven in unison with the rotor (102, 152) around the rotation axis, the second valve pin that is interconnected to the rotor (102, 152) being disposed and rotatable within the flow of injection fluid, wherein the second valve pin comprises an elongated shaft having an outer circumferential surface having discontinuous protrusions, grooves, projections, fins or apertures that are rotatably disposed within the injection fluid flowing through the flow channel, the protrusions, grooves, projections, fins or apertures generating a selected turbulence in the injection fluid flowing through the flow channel when the second valve pin is rotated around its pin axis. a first actuator and a second actuator, a closure valve pin having a pin axis, the closure valve pin being adapted to be controllably driven upstream and downstream along an axial path of travel through the flow channel such that a distal tip end (124, 124a) of the closure valve pin is driven into and out of a position that closes flow through the gate, the first actuator having a linear or axial driver drivable along a reciprocal path of travel coincident or parallel to the axial path of travel, the closure valve pin being interconnected to the first actuator such that the valve pin is driven along the axial path of travel and reciprocally upstream and downstream into and out of the position that closes flow through the gate, the second actuator comprising a rotor (102, 152) having a rotation axis, the rotor (102, 152) being interconnected to a second valve pin such that the second valve pin is rotatably driven in unison with the rotor (102, 152) around the rotation axis, the second valve pin that is interconnected to the rotor (102, 152) being disposed and rotatable within the flow of injection fluid, wherein the second valve pin comprises an elongated shaft having an outer circumferential surface having discontinuous protrusions, grooves, projections, fins or apertures that are rotatably disposed within the injection fluid flowing through the flow channel, the protrusions, grooves, projections, fins or apertures generating a selected turbulence in the injection fluid flowing through the flow channel when the second valve pin is rotated around its pin axis.