AFCOs new technology 5th coil spring allows for a wide range of preload adjustment. Racers can effectively tune the point of full application of engine torque to the rear tires in order to maximize acceleration off the corners in all track conditions. The soft primary rate of this spring is designed to improve forward bite during initial throttle application in the slickest of track conditions. The stiff secondary rate of this spring is designed to provide quick application of engine torque to the rear tires after initial acceleration has begun. The point at which engine torque is fully delivered to the rear tires is adjusted by changing the preload on the spring. A decrease in spring preload delays, whereas an increase in spring preload quickens the application of engine torque to the rear tires when the throttle is applied.