1986 Acura Legend -- Suspension
The performance potential of the Legend required a suspension system that would provide excellent directional stability and control over a wide variety of road surfaces, speeds and conditions. It was designed to provide good road feel and responsiveness as well as high degree of passenger comfort.
The popular MacPherson strut system, despite its attractive simplicity, was not deemed suitable. Instead, a double wishbone system was employed. It has a number of advantages: low shock absorber friction; improved camber control; and a compact design which allows more underhood space and a lower hood line.
In a typical MacPherson strut system, some braking, acceleration and cornering forces are transmitted to the chassis through the shock absorber resulting in high friction. Precise tuning of the shock absorbers in this kind of system, to achieve both optimum ride quality and excellent handling, is very difficult.
With the double wishbone system, however, control is much more precise. Excellent camber control is possible and the shock absorbers, since they're not load-bearing, operate more effectively. The upper arm is angled for proper anti-dive and anti-lift control. For added high speed directional stability, 5.0 mm of static caster trail has been incorporated in the front-end geometry. Toe change is minimized by a high degree of parallelism between the lower control arm and tie rod.
Further, the wide separation of the unequal length arms provides superior load dispersion, and permits the use of compliant bushings to isolate the passenger compartment from noise and road shock. Front suspension travel is 180 mm (7.08 in.).
A great deal of development was done to keep weight of suspension components to a minimum: 4 kg (8.8 lbs.) were saved by using a hollow stabilizer bar; high tensile springs; and forged steering knuckles.
The Legend's independent rear suspension is a Reduced Friction strut (RFS) system that complements the front double wishbone system. A large trailing arm is used to locate each wheel longitudinally and align its toe angle; a lower arm provides lateral location and carries the spring load as well; the damper strut has a low body mounting location. The primary objective was to reduce strut friction, and this was accomplished by locating the outboard pivot point of the lower arm as close as possible to the wheel center plane in order to minimize the outside forces acting on, and creating friction in, the damper struts.
The springs are mounted separately from the damper struts allowing greater inward inclination of the damper without encroaching into the :Luggage area. The added inclination of the strut also contributes to more favorable camber change. Particular attention was given to tuning the rear suspension bushing layout and rates to insure virtually no toe change in response to braking, cornering and road shock forces. Additionally, the Legend is equipped with a 12.5 mm rear stabilizer bar to minimize body roll.
The rear suspension has variable rate springs plus 200 mm (7.9-in.) of suspension travel, contributing to excellent ride characteristics under virtually all load conditions.