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HICAS (High Capacity Actively Controlled Suspension) is Nissan's rear wheel steering system found on cars ranging from the more recent Skyline and Z iterations to smaller models like the Nissan Cefiro (A31), 240SX/180SX and Nissan Serena/Nissan Largo. It is also found on models from Nissan's Infiniti division, such as the Q45 and the M45/M35. Unlike other four wheel steering systems, HICAS and Super HICAS are fitted to improve handling rather than as a parking aid.
Earlier HICAS versions used hydraulics to steer the rear wheels. The hydraulic system was powered by the power steering pump and used speed sensors to determine how much and in which direction to steer the rear wheels. Later versions, called Super HICAS, moved to an electric actuator for the rear steering rack, making the system much lighter. The Super HICAS system also used its own computer to control the system instead of speed sensors. HICAS and Super HICAS rear wheel steering is limited to about 1 degree in either direction.
HICAS was introduced on the 1986 Skyline GTS coupes (GTS, GTS-R, and GTS-X). The system was later adapted to work on many models in the Nissan range, beginning with the Passage GT.
HICAS is the acronym for Nissans rear wheel steering system named High Capacity Actively Controlled Steering. HICAS works using different sensors which calculate speed, steering angle and corner position the rear wheels are steered by a maximum of 1 degree based on these measurements. HICAS helps eliminate body and give the car a more nimble fell, it does it job well and is helpful for the average driver who doesn’t push the car to its limits.
On a racetrack however HICAS becomes to intrusive and unpredictable, particularly on long high-speed corners, counter-steering is often needed to correct the Skyline though the corner, this is not good for lap times. Race team’s usually use a lock bar to disable the HICAS system which improves the Skylines balance, resulting in more predicable handling and faster lap times.
Earlier skylines (the R32) used a hydraulic system which had speed sensors and used the power steering pump to steer the rear wheels. The newer version named Super HICAS was used from the R33 onward; electric actuators were used a long with a onboard computer, this version saved weight, and is said to be a much improved system.