HEADLINES

2011 Acura TSX - Chassis

INTRODUCTION

In keeping with its lean, athletic appearance, the 2011 TSX offers a flat ride that is free from excessive pitching motions, along with outstanding agility and steering precision. Several chassis developments (such as a highly rigid body design with a cross-braced roof structure and a safety cage-type rear bulkhead structure) help contribute to the TSX's dynamic performance. With the all-new TSX Sport Sedan, a special rear hoop structure generates excellent body rigidity, and a light weight tailgate structure keeps body mass low.

SUSPENSION

The TSX suspension's high roll center (the geometric axis on which the body rolls or leans while cornering) reduces body lean during cornering, which better equalizes the workload for all four tires while also improving passenger comfort.

Front suspension
Double-wishbone front suspension components include stamped-steel upper A-arms, cast-iron steering knuckles, cast-iron lower A-arms, coil-over dampers and a large front stabilizer bar. A robust steel subframe cradles the engine, transmission and lower suspension components, and mounts on rubber bushings tuned to reduce road and engine noise, vibration and harshness (NVH) without compromising handling agility or steering precision.

For the TSX fitted with the 3.5L V-6 engine, the front suspension has been upgraded with unique front springs and revised dampers. The revised suspension accounts for the increased weight of the 3.5L V-6 engine and generates a level of sporty handling that buyers will expect from the powerful TSX V-6 model.

Along with unique tuning for the Electronic Power Steering (EPS) system, the TSX Sport Wagon also makes use of dual-mode dampers that are specifically calibrated for the vehicle. Combined, the result is a wagon that drives like a sport sedan.

Rear suspension
The multi-link rear suspension includes stamped-steel upper A-arms, cast aluminum knuckles, double lower tubular lateral links, tubular-steel toe-control links, coil-over dampers and a large stabilizer bar. This suspension system provides excellent handling, together with a flatter ride and exceptional control of noise, vibration and harshness (NVH).

DUAL-MODE DAMPERS

All TSX models feature dual-mode dampers. While most conventional dampers are tuned to provide a compromise between ride comfort and sporty handling at different speeds, the TSX's dual-mode dampers are uniquely engineered to provide ideal damping rates at both low and high speeds.

With a typical suspension, damping forces rise with the speed of damper compression, such as occurs when the vehicle encounters road irregularities at high speed. This can cause significant ride harshness and noise that reduces passenger comfort and enjoyment. However, the TSX's dual-mode dampers are tuned to provide the ideal damping rates for comfort and smoothness at low speeds of damper compression, while also limiting the maximum damping forces to reduce ride harshness at higher speeds of damper compression. In this way, the TSX provides a wider range of comfortable ride quality and exceptional road holding under a wide variety of driving speeds and conditions.

Deflector plate technology
Acura's dual-mode dampers automatically adjust compression damping characteristics to suit the vehicle speed, cornering forces and road surface. The dampers use a unique "deflector plate stack" that deflects when the compression forces reach a certain level, such as when encountering a large bump or dip in the pavement at high speeds. When these severe forces act on an ordinary damper, oil cannot move quickly enough through the damping orifices and the effective damping rate climbs— resulting in an excessive shock transmitted into the vehicle body.

With the TSX's dual-mode dampers, when severe conditions are encountered, the plate stack momentarily deflects, allowing oil to pass through at a much higher rate (in essence "capping" the damping rate at a preset level). Allowing an increased flow rate in extreme situations noticeably reduces the shock transmitted into the vehicle body for improved comfort. Deflection of the plate stack is carefully calibrated and controlled by spring pressure force on the plate stack. The simplicity of the dual-mode damper system also means that no electronics or movable valves are required.

ELECTRIC POWER STEERING (EPS)

The TSX uses Electric Power Steering (EPS) which regulates steering via a computer-actuated electric motor. With the computer-controlled system, advanced algorithms built into the operating software allow for continuous fine-tuning of the steering assist forces so that minimal force is required at low speeds— such as when parking or maneuvering. Conversely, progressively higher steering effort is generated at higher speeds (such as when driving on the freeway) to deliver a sport-minded driving experience.

The EPS system found in the TSX is an evolution of an earlier EPS system found on the Acura NSX supercar. Its key features and advantages include:

  • The EPS system reduces the steering effort at low speeds, improving agility and ease of effort when parking or maneuvering in tight areas
  • Rigidity of the steering mount is higher, which allows a more precise and "connected" feel during high-speed maneuvers (such as during lane changes or when on winding mountain roads)
  • The EPS steering assist incorporates computer algorithms based on vehicle speed rather than engine speed, allowing TSX engineers the flexibility of tailoring the steering feel to match actual driving conditions— especially high-speed driving. The EPS steering algorithms incorporate steering assist changes for every 0.6 mph.
  • The EPS system is different (and uniquely tuned) for each of the TSX models: 2.4L I-4 sedan, 3.5L V-6 sedan, and the new Sport Wagon.
  • EPS employs a sporty, 13.5:1 steering ratio which further improves performance driving agility
  • In its evolution from the original NSX system, the TSX's EPS system uses a significantly more powerful electric motor teamed with a far more sophisticated microprocessor
  • By eliminating the conventional power steering pump assembly, EPS uses less engine power which improves acceleration and fuel efficiency

4-WHEEL DISC BRAKES WITH ABS

The 2011 Acura TSX features 4-wheel disc brakes. The front rotors measure 11.8 inches in diameter and are made of cast-iron with integrated radial vents for excellent heat dissipation and wear properties. At 11.1 inches diameter, the solid-type rear rotors provide enhanced braking capability during repeated use. Floating-style single-piston cast-iron brake calipers are used front and rear. For the TSX V-6, special rear brake pads are used. In addition, the V-6 model makes use of a larger brake master cylinder, a revised pedal ratio and a unique brake booster to deliver a more performance minded braking feel.

A sophisticated 4-channel Anti-lock Braking System (ABS) is standard and works in concert with the vehicle's Traction Control System (TCS), Brake Assist, and Vehicle Stability Assist (VSA) systems for an outstanding array of electronic dynamic aids.

WHEELS AND TIRES

The 2011 TSX sedan and TSX Sport Wagon come standard with 17x7.5-inch five-spoke aluminum alloy wheels that feature a new machined surface for the spokes. Fitted to the wheels are Michelin Pilot HX MXM4 P225/50R17 93V all-season tires developed specifically for the vehicle. For TSX V-6 models, the wheels are upgraded to 18x8-inches in size and are fitted with performance minded Michelin Pilot HX MXM4 P235/45R18 94V tires. All TSX wheels have a clear-coat finish designed to provide good looks and added protection when the wheels are exposed to harsh weather conditions. Located under the trunk floor panel is a T135/80D16 temporary spare tire mounted on a 16x4-inch steel wheel.

TESTING

Dynamic testing and chassis tuning for the TSX was conducted both in Japan and America. The TSX was specifically tuned for the best combination of agility and handling needed in an urban environment and at higher speeds. The Los Angeles area (with its huge variety of road surfaces, freeways and varied topography) proved invaluable in chassis tuning to achieve a balanced overall package. Also invaluable was a "mini-Nürburgring" test course built in Japan that is designed to replicate some of the most demanding elements of the famed German racetrack.

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