Hybrid cars are known to be oriented on reducing fuel consumption and emission levels. They are generally slow and not very pleasant to drive. Lexus has just changed that launching the first high performance hybrid vehicle, the GS 450h. With a total power of 345 bhp, this new Lexus can accelerate from 0 to 60 mph in under 6 seconds, reach a limited top speed of 155 mph with a combined fuel efficiency of 30 mpg.
As Shighetoshi Miyoshi, chief engineer at Lexus has stated, “the GS 450h, featuring the latest Lexus Hybrid Drive, is not only synonym for unparalleled performance; it provides the driver and passengers with class leading levels of active and passive safety. Reflecting the GS 450h customers’ attitude towards life, Lexus engineers achieved levels of NOx and HC emissions that, combined, are lower than any other combustion engine car on the market.”
Already on sale, the new Lexus GS 450h luxury sports sedan follows the highly acclaimed RX 400h SUV as the second production vehicle to introduce the technical sophistication and high-performance attributes of Lexus Hybrid Drive engineering to the premium automotive segment.
The new GS 450h is the world’s first full hybrid car to combine front engine mounting with the rear wheel drive, essential to sports driving dynamics. It defies the pre-established conventions of the luxury market by combining a level of performance that sits between conventional premium V8s and its high-performance counterparts. Its fuel efficiency compares to petrol vehicles two segments below with a fuel efficiency of more than 30 mpg.
Integrating the world’s most technologically advanced drive-train with the dynamic, elegant simplicity inherent in the new Lexus L-finesse design philosophy and the fundamental Lexus values of uncompromising luxury, state-of-the-art safety, impeccable refinement, peerless quality and sublime ride comfort, the new 2006 Lexus GS 450h re-defines the high performance luxury sedan.
The “450” name particle does not represent the petrol engine displacement in cubic inches but, rather, the recognition of a power output comparable to that of a conventional 4.5 liter, V8 petrol engine, developed according to the Lexus standards. The ‘h’ suffix indicates the presence of Lexus’ highly sophisticated hybrid drive system.
Lexus Hybrid Drive system was created around the principle of paradox, combining high levels of performance with fuel efficiency and emissions unachievable by comparable vehicles. A completely new, front engine, rear-wheel drive, series/parallel hybrid power-train has been engineered for the high performance GS 450h.
It features a 211 cui V6 petrol engine combining a new D-4S twin injector system
(Direct-injection 4-stroke Superior-version) with Dual VVT-i (Variable Valve Timingintelligent) to develop 296 bhp, mated to a compact, high-output, permanent magnet electric motor generating 200 bhp right from standstill. With a combined power output of 345 bhp, the GS 450h is not only the most powerful production hybrid in the world, but also the first to achieve the 100 bhp/liter barrier for specific output.
The new GS 450h’s Lexus Hybrid Drive system further comprises a generator, a high-performance, 288 V nickel-metal hydride battery, a Power Split Device which, via planetary gears, combines and re-allocates power from the engine, electric motor and generator according to operational requirements, and a new, more compact Power Control Unit no larger than an auxiliary 12 V battery.
Body & chassis
The GS 450h is the high performance flagship of the third generation GS model line up,
a range which represents the first production vehicle presentation of a radical new “L-finesse” Lexus design philosophy.
The GS 450h may be identified as the high-performance flagship of the GS range by the addition of a rear spoiler to the boot lid, discreet ‘Hybrid’ badging to the rear of the rocker plates and bespoke 18” alloy wheels.
The GS 450h platform comprises a highly rigid body structure featuring a weight saving aluminum bonnet. Extensive bracing within the floor platform offers enhanced torsional stiffness to significantly improve driving dynamics. Unique to the high performance model of the GS range, the carefully considered positioning of various Lexus Hybrid Drive components within the GS 450h platform awards the new Lexus luxury sedan 50:50 weight distribution between front and rear axles (including driver). Moreover, with a lighter engine (17% less than GS 430’s 4.3 litre V8 unit) and the mounting of the hybrid power-train’s heavier masses closer to the centre of gravity, the vehicle’s moment
of inertia is also improved over that of the GS 430, which means more agility. In addition, the GS 450h is equipped with a limited-slip differential which, allied to the location of the hybrid battery directly over the rear axle, further improves rear wheel traction.
Within an all new, third generation GS platform of exceptional torsion stiffness. The installation of the new high-performance Lexus Hybrid Drive system confers 50:50 weight distribution (including driver) and a better moment of inertia in comparison with GS 430, thanks to the 3.5 liter V6 engine, 17% lighter than the 4.3 liter V8. These aspects contribute to a more dynamic, agile handling.
Rear-wheel grip and traction are enhanced by positioning the hybrid system’s battery
directly over the rear axle, an aspect further improved by the installation of a limited-slip differential.
Coefficient of drag (Cd) 0.27
Kerb weight lbs (min.-max.) 4,112-4,255
Engine & transmission
The new GS 450h employs a 210.9 cui, 60 degree V6 petrol engine, which adopts the Otto cycle for performance orientation. It develops a maximum power of 296 bhp and 271 lb.ft of torque. For optimum weight saving, the engine block, cylinder heads, head covers, oil pan, pistons and bearings for both connecting rods and crankshaft are built in aluminum, and connecting rods are forged in high-tensile steel. Thanks to advanced casting techniques, the aluminum block and cast-iron liners are produced as a single unit, reducing the spacing between cylinder bores to just 0.45 inches.
Moreover, the engine’s integration within the Lexus Hybrid Drive system obviates the need for either a starter motor, alternator or serpentine belt, the V6 being started by the electric generator. The world’s first automotive application of two injectors per cylinder, D-4S (Direct injection 4-stroke petrol Superior version) is the latest evolution of Lexus’ stoichiometric, 4-stroke, direct injection technology. With one injector installed in the combustion chamber and a second mounted in the intake port, it combines the strengths of both direct and port injection, realizing optimum engine efficiency and improving torque by 7% across the rev range, whilst minimizing fuel consumption and emissions.
The system’s port injectors employ 12 holes to inject fuel at a maximum pressure of 4 bar, whilst the in-cylinder injectors feature twin, 0.02 x 0.005 inches rectangular slits producing a double fan injection pattern to effect the most homogenous possible air/fuel mix. In-cylinder injection is performed at a maximum pressure of 130 bar, a reference value for petrol engines.
Unique to the GS 450h, the hybrid transmission incorporates a two-stage motor speed reduction gear – a mechanism similar to a very compact automatic gearbox – generating maximum low-gear torque for significantly enhanced acceleration.
Electric motor, generator, Power Split Device and two-stage motor speed reduction gear are all housed in one lightweight, highly compact longitudinal transmission casing. In order to enable the installation of this component within the platform of the Lexus GS , engineers of the Lexus Devel opment Centre have devoted their attention to finding solutions to reduce its size. As a result, the GS 450h’s hybrid transmission is merely 0.5 inches longer than the 6-speed manual transmission of the Lexus IS.
Another world first, E-CVT (Electronically controlled Continuously Variable Transmission) with Sequential Shift Mode, offers a sequential operation mode. Each of the 6 sequential ‘steps’ offer sharper engine brake force in the manner of a conventional automatic transmission in sequential mode, improving vehicle control and further enhancing the new Lexus’s high performance sports driving experience.
The GS 450h will go from 0 to 60 mph in 5.8 seconds, keeping a linear acceleration up to a top speed of 155 mph, with none of the expected ‘jumps’ between gears of a conventional drive-train.
Conversely, the GS 450h also proves substantially more frugal than comparable V8
sedans, returning 35.8 mpg in the combined cycle. Moreover, the new Lexus returns CO2 emissions on par with 4-cylinder economy diesels of the same segment. In addition, GS 450h also achieves the market’s lowest levels of NOx and HC emissions combined, amongst vehicles equipped with combustion engines.
Combined power (DIN hp/kW) 345/254
Petrol engine type Layout 60-degree V6, longitudinally-mounted
Fuel type Petrol, 95 octane or more
Valve mechanism 4-valve per cylinder, chain driven; Dual VVT-i
Injection type D-4S (direct and port injection combined)
Injection pressure (bar) 130 (direct)/4 (port)
Bore x stroke (in.) 3.71.0 x 3.26
Compression ratio (:1) 11.8:1
Max. power (DIN hp/kW@rpm) 296 /218 @ 6,400
Electric motor Type AC synchronous, permanent magnet
Max. power (DIN hp/kW) 200/147
Electric generator Type AC synchronous, permanent magnet
Transmission Type Two-stage, longitudinal; rear-wheel drive 2-speed motor reduction gear ratios Low 3.900 High 1.900
Differential type Hypoid gear, limited slip
Final gear ratio 3.266
Number of cells 240 (6 x 40 modules)
0-60 mph (sec.) 5.8
The front, high-mount, double wishbone suspension system combines lightweight, forged aluminum knuckles with high tensile steel arms and a hollow anti-roll bar to reduce un-sprung weight. In addition, new, forward mounted power steering gear allied to low toe variation along the suspension stroke promote a more linear yaw response, precise steering control and excellent straight line, high speed stability.
To the rear, an advanced multilink set-up with toe control arms and an aluminum rear axle carrier combines stiffer suspension component materials with a reduction in un-sprung mass for excellent ride comfort with high cornering stability. The adoption of a double-linked upper arm and integrated bearings and hub combines optimized geometry and high rigidity with significant weight reduction. The utilization of a multilink configuration facilitates the optimum balance of handling, stability and ride comfort: The upper arms contribute to a reduction in upward spring motion, the mid-arm contributes to reduced body roll, and the lower arm provides an improved anti-lift / anti-squat ratio.
A sophisticated front double wishbone and rear multilink suspension format includes an Adaptive Variable Suspension system (AVS), with a choice of two damper settings to optimize ride and handling in either “Sport” or “Comfort” modes. Selecting “Sport” mode automatically increases the difference between inner and outer shock absorber damping through corners to further reduce body roll.
Front Suspension Front Double wishbone, aluminium knuckles and high-tensile steel arms
Rear Suspension 5-arm multi-link, aluminium rear-axle carrier
Shock absorber Gas-filled, monotube type, Adaptive Variable Suspension (variable absorber stiffness)
Front Brakes Four-piston calipers, ventilated discs (Ø13.1 x 1.18)
Rear Brakes One-piston calipers, ventilated discs (Ø12.2 x 0.7)
Additional Brake features Electronically Controlled Braking (ECB), Vehicle Dynamics, Integrated Management (VDIM), Hill-start Assist Control (HAC), Regenerative Brake System
The Electric Power Steering (EPS) incorporates Variable Gear Ratio Steering (VGRS)
which alters the steering gear ratio according to vehicle velocity, combining minimal low
speed effort with improved feel and feedback as speeds increase. The VGRS system is
linked to both the AVS system and Lexus’ unique Vehicle Dynamics Integrated Management system (VDIM), helping maintain vehicle stability and enhance driving enjoyment at the limit of the performance envelope.
Steering Type Rack & pinion, Electric Power Steering, Ratio 12.4 to 17.4, Turns (lock to lock) 2.7 to 3.7
Tires & wheels
The creation of a unique spatial perception within the passenger compartment is also central to the L-finesse rationale. The incisive simplicity and intriguing elegance inherent in the new design strategy combine proportion, architecture and surface to achieve a bold, “one motion” solution offering a seamless fusion of luxury and dynamic style. Structural elements such as instruments, centre console, air vents, handles and armrests have been painstakingly integrated within material finishes of the highest quality to create a modern design graphic, which emphasizes the continuous, three-dimensional qualities of the interior space.
The GS 450h is equipped with a comprehensive range of technologically advanced
equipment designed to both simplify and enhance life on board. The Lexus ownership
experience is founded on the principles of discreet hospitality and carefully considered
driver interaction, and this is exemplified within the new GS 450h, from the moment of initial approach to the vehicle, through convenient, Smart Key access, and bespoke illumination sequenced to correspond with the entry or egress of driver and passengers.
Push button engine start-up further negates the use of a key, and steering sensitive parking sonar offers a unique, steering angle related aid to low speed maneuvering.
The new Lexus features the only fully electric climate control system in the segment, equipping the GS 450h with an electric compressor and water pump that minimize the loss in fuel economy and performance in comparison with conventional systems.
Going much beyond conventional notions of perceived quality, engineers of the Lexus
Development Centre have focused on detail aspects that denounce the brand’s path in the pursuit of perfection - like the activation of all the buttons, lids and mechanisms found within the cabin of GS 450h. For instance, several components were redesigned in order to reduce the noise originated when opening compartments to levels below 45 dB. Similarly, the opening speed variation of the glove-box was reduced from 25 to 10% by minimizing mechanism frictions.
An interesting feature in the GS 450h’s interior is the Electronic Chromatic Device (ECD) uses the information provided by a light sensor built into the high mounted rear stop lamp to automatically adjust the intensity of the Optitron instrument dials to optimize visibility under all conditions.
The Lexus Multimedia and Navigation System includes a Mark Levinson Premium Surround system capable of reproducing a complete, discrete 5.1 DVD home theatre experience. A new satellite navigation system which includes traffic avoidance technology and incorporates both a 7” Electro Multi Vision touch-screen display and a voice command system for control of audio, air-conditioning, navigation and Bluetooth wireless phone operation is also offered. The system further incorporates the Lexus Parking Assist Monitor, a feature unique to this automotive segment.
The new Lexus GS 450h is comprehensively equipped with the most technologically
advanced pre-emptive, active and passive safety systems available on the market today.
A Pre-Crash Safety system (PCS) pre-emptively optimises front seat belt and emergency
braking systems to help reduce collision damage and injury, whilst a complementary
Adaptive Cruise Control system (ACC) automatically matches the speed of the new
The GS 450h features the latest generation of Lexus’ state-of-the-art Vehicle Dynamics
Integrated Management (VDIM), integrating the Anti-Lock Brakes (ABS), Electronic
Brakeforce Distribution (EBD), Traction Control (TRC) and Vehicle Stability Control (VSC) active safety systems with the Active Variable Suspension (AVS), Electronic Power Steering (EPS) and Variable Gear Ratio Steering (VGRS) systems to enhance performance, traction control and vehicle stability.
The new Lexus GS 450h comprises the most complete airbag passenger protection
in class: two-stage frontal (two), knee (two), curtain shield (front and rear) and side (four,
optional at the rear) airbags. In addition, GS 450h features 4 lateral collision sensors that
Seatbelt pretensioners with force limiter are available at the front and rear outer seats.
TopSpeed artists Lexus GS 450h tuning recommendation
This is an unusual vehicle for tuning, a large saloon, with a hybrid driving system. However, in terms of performance it is in the same league with the Audi S6, Jaguar S-Type R or Mercedes E55 AMG. The looks unfortunately are not at competition level, so we decided to adjust the visual “WOW” factor of the car. First, we replaced the front bumper with one adapted from a Lexus IS . We love how that spoiler looks; it is both aggressive and elegant, and carries the Lexus genes. Sporty side skirts further improve the aerodynamics and lower a bit the ride height. We didn’t like the truck-like rear mirrors of the standard GS, so we had them replaced with some taken from a Lexus SC . To emphasize that this is a “greener” car we have set up a very special paintwork. The front of the car has a chameleon green-golden tint that fades towards the back in a dark blue metallic paint. To state clearly that this is a hybrid vehicle with environment protection concerns we also painted some maple leaves on both sides. Like for any high-performance vehicle, a set of matching rims were required. We have chosen the wheels featured on the Lexus prototype that appeared in ‘Minority Report’ in 20” diameter. All that and the ‘TopSpeed’ logo on the front grille and your “eco-racer” is good to go.