AFCO Progressive 5th Coil Spring - 2-8/5" x 11" Tall

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.

Highlights:

wide range of preload adjustment

soft primary rate (improves forward bite)

stiff secondary rate (provides quick application of engine torque to rear tires) LIT20087PR Tuning Guide:

Start with at least inch preload

Too much preload may cause loose on-throttle handling in slick track conditions and tight on-throttle handling in medium to heavy traction conditions

Too little preload can excessively delay launch off the corners in all track conditions

In most cases, preload amounts from to inch are used (adjust in increments to start)