Lexus, the car company: this all-new sports sedan is just the beginning of things to come for Lexus

Automotive Industries, March, 2005 by Rich Wilson

The Lexus GS is the first new car from Lexus since September 2001. The product of a 40-month development period, Lexus engineers focused on increasing the performance they felt was lacking in the previous generation benchmarking it against the BMW 5-series.

So what's new on the GS?

Nearly everything.

The GS comes with a choice of two engines. The 3.0L V-6 (coded 3GR-FSE) has four valves per cylinder with dual intelligent variable valve timing as well as direct cylinder injection. The V-6 produces 245 hp at 6,200 rpm and 230 lb. ft. of torque at 3,600 rpm. The 4.3L V-8 (coded 3UZ-FE) also features four valves per cylinder, continuously variable intelligent valve timing and sequential multi-port fuel injection. The V-8 makes 300 hp at 5,600 rpm and 325 lb.ft. of torque at 6,350 rpm. Zero to 60 times are 6.8 and 5.7 seconds with top speeds of 143 and 149, respectively.

Both six- and eight-cylinder models are mated to a new dose-ratio &speed automatic transmission with an auto-stick option, allowing the driver to make the gear selections.

New for the GS is an all-wheel-drive option, available on the GS 300, the first all-wheel-drive car produced by Lexus. The AWD system uses a wet-type multi-disc clutch along with a planetary gearset in the transfer case. The system also makes use of an electronic control strategy that collects information from wheel speed and yaw sensors as well as throttle angle and steering input. Hydraulic controls are used to vary the front/rear torque split from 30/70 to 50/50. The normal modus operandi is the 30/70 split, giving the car a rear-wheal-drive feel under normal circumstances with the 50/50 kicking in when loss of traction is detected.

Complementing the AWD system is Electronic Traction Control. When wheal slippage is detected, the system applies braking to the slipping wheel(s) and transfers the torque to the non-slipping wheel(s) on the same axle. Between traction control and the hydraulic torque split, Lexus has complete electronic control of the AWD system.

The AWD-optioned GS300 is aimed at the snow markets--particularly the Northeast. Lexus feels that, competing against Mercedes' 4matic and BMW's X-drive, the lack of an AWD system would limit sales in that region. Lexus expects 42 percent of V-6 buyers to opt for the $1,950 option, which also includes run flat tires.

The exterior design has been changed quite a bit. While LF-concept touches are most prominent in the headlights, subtle LF design cues are carried throughout the vehicle. The new design language isn't all about the signature Lexus look. The new GS sedans boast a .27 coefficient of drag.

While all the basics, like aerodynamics and powertrain were carefully considered, Lexus also kept its focus on offering the luxury sedan buyer all the accoutrements they'd expect and a few more, just for good measure.

Among the litany of features for the GS is the Smart Access keyless entry/start, presumably akin to the system seen on the Toyota Prius and Avalon. The driver needs only to have the key fob in their possession when approaching the car. Sensors detect the driver's presence and unlocks the doors and start a lighting sequence that first, illuminates the side mirror and area directly around the door. Once the door is opened, soft blue lights come on in the foot wells. The only thing missing is a "sounds of nature" cd that could very easily be placed in the optional Mark Levinson premium surround sound stereo system. The 5.1 surround sound audio system features 14 speakers, 330 total watts of power and, according to Levinson, has less than 0.1 percent harmonic distortion.

Some of the other bells and whistles added to the GS have a lot more serious issues at heart. The Vehicle Dynamics Integrated Management system is designed to integrate and manage the Electronically Brake Distribution system (EBD), Electronic Power Steering (EPS), Variable Gear Ratio Steering (VGRS), Vehicle Stability Control (VSC), Brake Assist (BA), Electronic Brake force Distribution (EBD) and engine torque via the electronically controlled throttle. The system collects data from all the sensors and anticipates vehicle skids assisting the driver in controlling the vehicle. The use of throttle-by-wire and steering, that is nearly "by-wire," lent itself to this process.

The steering system is comprised of a brush-less electric motor integrated into the steering rack. This eliminates the need for any hydraulic power steering apparatus. The "pinion" part of the steering assembly is really just a torque sensor. Inside the unit is a torsion shaft with torque sensors on each end, known as "resolvers."

When the driver creates steering input, the "resolvers" measure the amount of twist generated in the torsion bar, end versus end, comparing the readings from both ends of the torsion bar. When the amount of twist reaches a predetermined value, the ECU analyzes speed, yaw rate and steering angle measurements and determines if Intervention is needed. If driver assist is necessary the ECU engages the electric motor and provides the voltage needed to provide the prescribed assist.