The ThunderMax® EFI system includes a new, pre-programmed ThunderMax® ECM loaded with a dedicated base map developed by Zipper’s Performance Products specifically for this kit (add optional AutoTune for full time closed-loop AFR correction!) What you feel is super smooth power and drivability at any RPM due to the extra-wide torque curve and our high-resolution base map. Twist the grip on your Twin Cam®, and Unleash the Power – It’s a blast to ride!