Tech Review: 2007 Lexus GS 450h
Driving green doesn't mean you have to sacrifice performance.
- Good fuel economy and performance
- Quiet and smooth ride
- Excellent audio system
- The higher initial cost of a hybrid
- Archaic cassette deck
- Nav system's voice (non)activation
What could be more technologically innovative, eco-friendly and fun than a refined rear-wheel-drive hybrid "luxury performance" sedan like the 2007 Lexus GS 450h? The quick answer to that question is nothing, at the moment at least, since Lexus is the only automaker that's taken a stab at the segment.
Getting top tech billing is GS 450h's Lexus Hybrid Drive system, which mates a 3.5-liter V6 engine with a permanent-magnet electric motor to crank out 340 horses. Lexus claims the hybrid powerplant will propel the GS 450h from 0 to 60 in 5.2 seconds, and that the system delivers its optimal performance during midrange acceleration, specifically in the 30-to-50 mph range. Based on the week I spent with a GS 450h test vehicle that stickered at $65,794 we wouldn't dispute that.
But perhaps the biggest thrill came at the gas pump—or, more specifically, how many times I passed one by without having to refuel. The GS 450h has an EPA-estimated fuel economy rating of 25 mpg city, 28 highway and 26 combined. While that's only about half the mpg rating of the car's distant cousin and hybrid poster child the Toyota Prius, the GS 450h also doesn't make the same (over)statement on the street as a Prius.
Lexus refers to the GS 450h as a "full hybrid" since it's capable of operating in gas- and electric-only modes as well as a combination of the two. The hybrid powertrain uses a pair of motor-generators.
One solely serves as a starter motor, charges the 228-volt DC Nickel-Metal Hydride (Ni-MH) battery pack behind the rear seat and also supplies additional power to the second motor-generator, which provides motive force. The Ni-MH battery's power is funneled to a "boost converter" that steps up voltage to 650 volts DC, and then an inverter switches the juice to AC to provide power to a 147-kilowatt electric motor. A standard 12-volt auxiliary battery in the trunk powers vehicle systems such as audio and navigation.
Power from the gas engine and second electric drive motor is transferred to the rear wheels through an Electronically controlled Continously Variable Transmission (ECVT) that uses a two-speed torque multiplier and offers one of three driving modes.
Normal is for city driving, Power provides more responsive acceleration and Snow mode moderates accelerator response. I (unfortunately) had to use the Snow mode quite a bit during our mid-winter test period and didn't get the chance to use the Power mode as much as I would have liked. And I (fortunately) also didn't get to test the car's optional Pre-Collision System (PCS), which uses a radar sensor to detect obstacles in the car's path and reacts if the driver doesn't.
If speed, steering angle and yaw-rate data inputs determine that a crash in imminent, the system switches the suspension to sport mode for the best chassis response, tightens the front seat belts and puts the Brake Assist system on red alert. Should a driver not heed the PCS's warning, an active-braking system will slowly apply the brakes.
More Time for Music
The '07 GS 450h has the Lexus hallmarks of a quiet, comfortable ride and well-mannered handling. It comes standard with Adaptive Variable Suspension that allows dialing in the level of shock-absorber damping, and our test model was equipped with an optional Active Vehicle Stabilizer system that anticipates excess body sway during cornering and applies pressure to the front and rear stabilizer bars via electronic actuators.
The system kept the 4,100-pound sedan poised around sharp turns at moderate speed. And the Vehicle Dynamic Integrated Management (VDIM) system that employs a combo of braking, throttle and steering keeps the car from coming unglued from the pavement.
Knowing that all of this safety and suspension tech was doing its job without having to even think about it gave me peace of mind to soak the sound of the optional and excellent 14-speaker, 330-watt Mark Levinson Premium Surround Sound Audio system. Lexus and Mark Levinson simply have once again set the benchmark for OEM audio with the latest generation of 7.1 systems. But it is time to replace the archaic cassette deck at the bottom of the center stack with an aux-in jack, however.
The 7-inch touch-screen in the middle of the dash with large buttons flanking it made the audio system as well as the DVD navigation system easy to use. And while the nav system worked well, the voice-activation feature did not and required repeating commands enough that I'd usually give up and just enter the destination info (literally) by hand.
All Fun, No Guilt
The GS 450h had many other high-tech touches—adaptive front lighting, heated and ventilated front seats, SmartAccess with push-button starting—that makes this a hybrid that's smart as well as sensible.
In fact, if it wasn't for the quiet ride—and the display in the instrument panel that shows power flowing to and from the batteries, the engine and the brakes (through regenerative braking), it was easy to forget I was even driving a hybrid. With its sporty performance, creature comforts and more than ample tech, the GS 450h lets conscientious car buyers have all the fun with none of the guilt.
Doug Newcomb has been writing about car electronics since 1988, as editor of Car Audio and Electronics, Car Stereo Review, Mobile Entertainment, Road & Track Road Gear and as a freelance writer. His new book, Car Audio for Dummies, is available from Wiley Publications. He lives in Hood River, Oregon.