1991 ACURA NSX tires

System Description

Suspension Composition

Outline

Double wishbone independent suspension has been selected for each of the four wheels. This eliminates damper friction

along the steering axis, and permits suspension geometry that takes full advantage of the performance potential of the

wide, low aspect ratio tires. The double wishbone design also allows the use of aerodynamically-efficient and

aesthetically pleasing low fender lines.

The knuckles and the suspension arms are manufactured from lightweight, high-strength aluminum alloys. This gives a

notable reduction in unsprung weight which results in increased traction and improved ride. It also allows the individual

suspension components to be designed in detail for maximum strength and rigidity.

FRONT

UPPER

CONTROL

ARM
KNUCKLE

STABILIZER
REAR

UPPER

CONTROL

ARM
STABILIZER

KNUCKLE

LOWER CONTROL ARM

LOWER CONTROL ARM

To further increase suspension link rigidity, and to obtain optimum knuckle geometry, the knuckles and ball joints are

contained within the wheel profile. At each corner of the car, the individual suspension system is attached to the alumi-

num stressed skin chassis by a cast aluminum sub-frame. This design further reduces overall weight, and ensures that

suspension loads are fed into the chassis at the most efficient points, and in the most efficient directions.

A large front caster angle combined with small trail distance improves straight-line stability and response without caus-

ing heavy steering effort.

FRONT
REAR

SUB-FRAME

SUB-FRAMEProCarManuals.com

Wheel Alignment

Height

NSX/NSX-T four wheel alignment requires the use of equipment designed specifically for four wheel independent

suspensions and capable of immediate feedback.

NOTE: For proper inspection/adjustment of the wheel alignment, check and adjust the following before checking

the alignment.

• Check that the suspension is not modified.

• Check the tire size and tire pressure.

• Check the runout of the wheels and tires.

• Check the suspension ball joints. (Hold a wheel with your hands, then move the wheel up and down and right

and left to check for wobbling.)

• Check the height of each suspension (see below).

Standard value

Front:

Ground clearance to the center of the lower

control arm bolt
Rear:

Ground clearance to the center of the toe con-

trol arm bolt

Height inspection:

• Before checking for the height, bounce the car up and down several times before measuring.

• Check the height with the car empty, parked on a level surface, with properly inflated tires (tread wear indicators must

not be showing). If the height is out of specification, load or unload the car as necessary.ProCarManuals.com

System Description

TCS Control unit

Acceleration Control:

The TCS control unit gets signals from the wheel sensors about the rotational speed of each wheel. Traction control

is activated when the rotational speed of the driving wheels differs from the rotational speed of the driven wheels (i.e.,

vehicle speed).

Handling Control:

Based on signals about driving wheel and driven wheel rotational speeds, the control unit calculates the car's "yaw"

rate (i.e., the turn rate of the car's body). Based on signals from the steering angle sensor, the control unit also calculates

the yaw rate expected by the driver. If the difference between actual and expected yaw rates is substantial—that is,

if the direction of the car's body will exceed the driver's expected line—the control unit signals the throttle actuator,

which closes the throttle valve, thus reducing engine power and maintaining the expected line.

Rough Road Control:

Based on signals from the wheel sensors, the control unit detects a rough road based on frequency of wheel rotational

vibration. The control unit then signals the throttle actuator to relax engine power, thus improving acceleration efficiency.

Grip Control:

Based on signals about wheel speed and yaw rate, the control unit determines the efficiency of the grip of the tires on

the road and signals the throttle actuator to relax engine power if necessary, thus improving grip.
Construction and Function

DRIVE WHEELS

Right wheel

Left wheel
WHEEL SENSORS

Driving Wheel

Speed
Average speed

of left and

right wheels

Vehicle speed

Advance acceleration

Tire grip control

Acceleration

control

Target slip

ratio

Engine control block

ENGINE CONTROL

MODULE (ECM)
Throttle actuator (step motor)
Throttle valve control
Handling control
Rough road

detection

Rough road

control
Reference yaw rate

Lateral

acceleration
TCS CONTROL UNIT
STEERING ANGLE SENSOR

DRIVEN WHEELS

Right wheel
Left wheel

Actual

yaw rate
Rotational

vibration
Speed difference in the

left and right wheelsProCarManuals.com