Nissan 240SX - Basics
Super HICAS (High Capacity Actively Controlled Suspension) is Nissan’s four-wheel steering system used on the 240SX. A similar system is used on the Nissan Skyline. Early HICAS designs used hydraulics for rear steering, but Super HICAS uses electronic actuators controlled by the ECM.
Four-wheel steering on the 240SX is designed to improve low-speed maneuverability and high-speed stability, especially during lane changes. Super HICAS operates in two modes: in-phase steering and opposite-phase steering. Opposite-phase steering, utilized at low speeds, turns the rear wheels in the opposite direction of the front wheels to reduce turning radius. In-phase steering, utilized at high speeds, turns the rear wheels in the same direction as the front wheels to reduce sideways motion of the car, thereby increasing stability. The steering angle of the rear wheels is limited to about one degree.
Super HICAS may facilitate better steering response and quicker corner entry in racing conditions by delaying in-phase steering or using some opposite phase steering at corner entry. However, racing with Super HICAS requires the development of a different driving style as compared to that required for an ordinary front-steering car. Many drivers report that the 240SX feels twitchy on corner entry with the use of Super HICAS. Also, the rear steering becomes unpredictable when the car is on the edge of losing traction. Therefore, most drivers prefer to deactivate the system with an aftermarket HICAS eliminator kit (see Performance section).