Building on the success of the first generation CTS sport sedan, Cadillac’s development team set even higher targets for every aspect of the driving dynamics of the all-new 2008 version. The goal was to reach handling limits near sports-car levels, while also adopting the poise and smoothness of prestigious luxury sedans.

With a 50-mm wider track and input from Cadillac's acclaimed V-Series models, Cadillac sent the new CTS back to the famed Nürburgring track. The engineering team also exhaustively road-tested the car on city streets and country roads across China, North Americaand Europe. The result is improved chassis hardware and a more finely tuned car.

Engineers designed and developed new geometry for both the independent short/long arm front suspension and the multilink rear suspension, driven primarily by the wider track and the application of all-wheel drive. The front track is now 1,569 mm, and rear track is 1,575 mm. The wheelbase remains at 2,880 mm. Three suspension levels are offered: FE1, FE2 and the performance-oriented FE3 (rear-drive only); each is tuned for specific ride and handling characteristics, and availability varies by market.

“The FE1 suspension is designed for excellent daily driving comfort, while the FE2 suspension adds a more sporting feel,” said Rob Kotarak, lead development engineer. “The FE3-equipped CTS is for serious performance.”

Engineers also tuned the suspension using extensive computer modeling, combined with development driving of prototype cars on three continents. The use of aluminum, for example, in the upper and lower front control arms and knuckles helps reduce mass and contributes to higher limits in handling and dynamic wheel control.

“Each suspension level is very specific to the needs and wants of drivers and we believe we’ve covered the spectrum in a way that balances a smooth ride with precise handling,” said Kotarak. “We knew the dynamics of the new Cadillac CTS had to be outstanding because our intent is to compete with the finest ride-tuned vehicles in the world.”

Road impacts and other harsh impacts are effectively absorbed and dissipated through ride-tuned tires, dampers, advanced chassis controls, suspension components and bushings. Also, stiff body-to-chassis interfaces, including refinements in engine mounting, contribute to an outstanding acoustic sensitivity of only 2 decibels. Additional chassis changes and revisions include:

New geometries for the independent SLAfront and multilink rear suspensions

New engine cradle designs for RWD and AWD configurations

Standard, high-precision ZF Servotronic steering gear, with higher resonant frequency steering column and torsionally stiffer intermediate shaft

Larger brake packages, including available performance brakes

New 17 x 8-inch and 18 x 8.5-inch wheels

New underhood tower-to-tower brace

New rear cradle and differential design for reduced noise and vibration

Revised engine mounting strategy

Along with its finely tuned hardware, the 2008 Cadillac CTS features advanced chassis technology and integrated control technologies, including four-wheel disc brakes with ABS, traction control, four-channel StabiliTrak electronic stability control, dynamic rear proportioning, engine drag control and hydraulic brake assist. 

Independent SLAfront suspension

The performance characteristics of the independent short/long arm (SLA) front suspension were optimized using computer simulation and extensive vehicle development work at locations in North America, Europeand China. The suspension system includes the use of aluminum for the upper and lower controls, as well as the knuckles, which reduces overall mass. This reduces unsprung mass, contributing to more nimble handling and dynamic wheel control. It also requires less damping and provides better road-holding capability.

Hydraulic control arm front bushings are used for motion control and help to minimize high-speed road vibration by damping energy transmitted through the vehicle structure. Also, hollow front stabilizer bars bring weight savings and are sized specifically to each of the three available suspension levels.

The front shocks on all models are monotube dampers from Bilstein and provide highly responsive damping from road inputs. A high gas charge of up to 350 psi prevents cavitation, avoiding the rough ride characteristics associated with lag in the damper’s absorbing quality. Larger, more complex shock mounts enable the shocks to deliver a larger rate change from extension through compression, contributing to the CTS’ improved ride characteristics.

Additional front suspension refinements on RWD vehicles include an increased roll-center height; caster increased by one degree, lower-friction ball joints and revised bushing rates. Impact isolation refinements on RWD models also include revised geometry that actually enables the wheels to move rearward and away from a bump or hole. Geometry changes also took friction out of the ball joints, which help enhance ride motions and improve the steering feel.

Engine cradle

The Cadillac CTS’ engine cradle is solid-mounted to the engine compartment rails for a precise feel. It is exceptionally stiff, which helps isolate noise, enhance handling and optimize crash performance. The cradle has six attachment points – two more than most performance sedans – to better handle heavier drive loads and energy pulses.

The engine cradle in RWD models is made of aluminum, which weighs approximately 35 percent less than the steel version in previous models. The reduced mass of the aluminum cradle not only saves weight, it helps optimize the car’s weight balance – and with the battery of the ’08 CTS relocated to the rear of the vehicle, the weight balance of RWD models is nearly 50/50.

An underhood tower-to-tower brace is standard on all models and adds cross-vehicle stiffness, for a greater feeling of solidity and a more precise steering feel. A component derived from the first-generation CTS-V, the brightly finished tower-to-tower brace is prominent in the car’s underhood appearance, stretching across the engine compartment.

Multilink rear suspension

A fully independent multilink rear suspension with isolated subframe is a hallmark of the CTS and is an uncompromising design with excellent suspension kinematics. In short, it enables superior ride and handling performance. Additionally, other rear suspension features control loads and help maintain stability during dynamic driving situations, helping the CTS balance ride quality and high-performance handling capability.

The multilink design provides maximum tuning flexibility so that the suspension can be tuned to react in a predetermined manner, such as during high-lateral cornering forces, where the rear wheels will respond with the correct camber and toe to avoid rapid destabilizing changes. Rear suspension details include aluminum upper control arms, knuckles and brake calipers, which optimize performance through reduced mass. They also epitomize the CTS’ use of premium materials and hardware.

The rear suspension cradle is more than 40 percent stiffer than its predecessor and is isolated with four large, complex rubber mounts that reduce noise transmitted through the vehicle. The mounts also provide soft characteristics in fore/aft movements yet are laterally stiff. As a result, the mounts provide flex when bumps are encountered, but remain stiff in cross-vehicle dynamics.

Like the front suspension, the rear uses hollow stabilizer bars – sized specifically to the suspension level – monotube Bilstein shocks, larger shock mounts and revised geometry that enables the wheels to move rearward when they encounter a bump or hole. FE3-equipped models include load-leveling shocks, which adjust automatically to different loads and road conditions. Steering and ride comfort are maintained during leveling periods and after unloading, the level returns automatically to the normal setting.

More noise reduction comes from the double-isolated rear differential. Also, the gear sets within the aluminum differential housing are matched to assure smooth, quiet performance.

Steering

The standard rack-and-pinion steering system uses a premium ZF Servotronic II speed-sensitive steering gear. The system has a variable ratio, speed-sensitive assistance and offers a turning diameter of 17.2 meters on RWD models and 17.4 meters on AWD models; and only 2.8 turns, lock to lock.

The ZF steering system incorporates great torsional stiffness with less operating friction, resulting in exceptional steering precision and linear response, with very smooth and predictable transitions. Additionally, the steering column and intermediate shaft are stiffened and use few joints. The result is a reduction in overall lash and an enhanced feeling of connection between the driver and the road. Also, the front suspension’s new, lower-friction ball joints contribute to the steering performance, enhancing its feeling of smoothness and refinement.

Brake systems

Four-wheel disc brakes with ABS and traction control are standard on all models. The front and rear brakes feature vented disc rotors; with aluminum calipers on the standard system and cast iron calipers on the 18-inch package. The front rotors on the uplevel brake package, at 346 mm in diameter, are 10 percent larger than the standard brakes’ 315mm rotors. Regardless of the package, the front calipers use twin, 42mm pistons and single rear pistons – 47mm pistons on the standard package and 45mm pistons on the uplevel system.

The brake pads are tuned to deliver long-term performance and a consistent, smooth feel. FE3-equipped vehicles use cast iron calipers for their strength and heat dissipation attributes during high-performance driving.

Chassis control systems

The ’08 CTS features numerous chassis control systems that are designed to help the driver maintain a safe driving path in all driving conditions. The systems include:

Anti-lock brakes (ABS) – a four-channel system that allows individual wheel braking and includes a sensor that differentiates between straight-line braking and corner braking, which helps minimize yaw

Dynamic rear brake proportioning – regulates braking pressure to optimize stopping distances and control under all load conditions

Traction control system –integrated with ABS, it is an all-speed, four-channel system that combines both torque and brake control to regulate wheel spin

Hydraulic brake assist –when panic braking is detected, the system automatically develops additional brake pressure to more quickly engage ABS, potentially reducing overall stopping distance by eliminating the delay caused by not braking hard enough and/or soon enough

Engine drag control –senses the difference in speed between free-rolling wheels, such as the front wheels on RWD models, and driven wheels that often occurs on low-coefficient surfaces when the driver lifts off the throttle, sending more torque to the driven wheels. This helps ensure all four wheels are spinning at similar speeds, resulting in enhanced stability and better overall driving dynamics

Also standard on all models is StabilTrak, GM’s electronic stability control system. It primarily integrates the ABS and traction control systems in response to yaw and steering inputs, helping to determine the driver’s intentions to maintain control during demanding or adverse conditions.