http://www.thecarconnection.com/Vehi...74.A10059.html
2007 Lexus GS450h
Can hybrid technology make a great sedan even better?
The Big Island of Hawaii is a land of surprises. Along the warm, dry Kona Coast it's sunshine, swimming, and golf. But just ten miles away, along the cross-island Saddle Road , a torrential rain is pummeling down, while a blizzard scours the island's twin volcanic peaks.
So it was an unexpectedly appropriate place to go for our first drive of the 2007 Lexus GS450h, a sedan that delivers a variety of its own surprises. The new model could very well redefine both the Lexus brand and the concept of hybrid-electric vehicles.
"Hybrid" is, of course, what the little "h" stands for, making this the second gasoline-electric offering in the Lexus lineup. The first, the RX400h, debuted barely a year ago. A version of the automaker's crossover wagon, it's proved both immensely popular and quite controversial. Like the little Prius sedan sold by parent company, Toyota , Lexus bills the RX400h as an environmentally friendly vehicle whose high-mileage technology reduces both emissions and reliance on imported oil.
In real-world use, the RX is more about feeling good than helping Mother Earth. Some reviewers, including those at TheCarConnection.com and The New York Times, have gotten just 21 mpg. Polling owners, the enthusiast site, GreenHybrids.com, got the average closer to 25 mpg, still a significant shortfall from the 33 City/28 Highway sticker. But if you don't save much fuel, there's the feel-good factor - and the access to the diamond commuter lanes with one person onboard, offsetting the steep hybrid price penalty.
Well aware of the controversy, Lexus is nonetheless still singing a green tune as it prepares to launch the GS450h. But it is fine-tuning that message. The emphasis here is on environmentally sensitive performance.
Cleaner than the average car
The sedan, boasted chief engineer Shigetoshi Miyoshi, is "80 percent cleaner than the average car." But during a background briefing, he put the real emphasis on the fact that the new hybrid is not only the fastest-ever Lexus, but with
a 0-60 time of 5.2 seconds, quicker than a Porsche 911 with the Tiptronic transmission. Top speed is a limited 131 mph for the U.S. version.
Will you also get better mileage? Well, it depends. Almost certainly better than a 4.5-liter V-8, which officials claim is what you'd need to get comparable performance - and why the 3.5-liter sedan is designated the GS450h, rather than GS350h. According to Lexus, the '07 hybrid should match the fuel consumption of a stingy, 2.5-liter in-line four, rated 27 mpg City and 28 Highway.
Well, that's what the window sticker is likely to show. But we wouldn't expect that in everyday use. Sure, in heavy L.A. traffic, you'll spend time in electric-only mode. But stomp on the drive-by-wire throttle and you're going to drain a lot of that imported petrol. During several admittedly brief runs around the Big Island , our test GS delivered results ranging from 19.3 to 24.4 mpg. Steep hills and hard acceleration, as you'd expect, quickly slashed away at the numbers.
Now, as we tore through the Hawaiian countryside, we have to admit, we weren't all that worried about fuel economy. This hybrid-electric proved an absolute, er, gas to drive.
Flat-out performance is exhilarating. The throttle nailed, you quickly sank back into the sedan's well-bolstered seats. Thanks to the "electric supercharging" system, the GS kept pulling as long as there was power in the batteries. And we found no noticeable loss in performance as we climbed to higher altitudes on this well-terraced island.
With last year's introduction of the GS sedan, Lexus took a great leap forward. As the division's general manager, Bob Carter, readily admits, this is not a brand known for its high emotional quotient. Parent Toyota is trying to change that. It has set up a separate Lexus board of directors, engineering arm and design center. And the '06 GS made great use of the division's stylish new design theme, known internally as L-finesse.
Lexus chose not to plaster the word, "hybrid," all over the vehicle, preferring discreet badging and otherwise subtle visual differences from the standard GS sedan.
Synergy at work
What matters most is largely found under the skin. Lift the hood and you'll discover an engine cover emblazoned, " Hybrid Synergy Drive ." It's an extraordinarily complicated package of technology - and not easy to boil down to a paragraph, but let's try.
The 292-hp V-6 delivers power through a new hybrid transmission specifically developed for the GS450h (and likely other high-performance models to follow). The transmission can also be driven by the most powerful hybrid twin-electric motor system Toyota has ever built, which is capable of punching out 197 hp and lots of on-demand torque.
(Don't try to add the horsepower ratings of the gas engine and electric motors. It doesn't work that way. All told, the GS450h makes a maximum 339 hp.)
When slowing or coasting, the synergy drive system can recapture waste energy, as can the vehicle's so-called regenerative brakes, which create current, rather than waste heat. This power can be re-directed to the electric motor, or recycled into 40 nickel-metal-hydride batteries.
The hybrid package is smaller and lighter than that used in other Toyota hybrids, notably the RX400h. That reflects the emphasis on performance over mileage, as well as the need to provide reasonable cargo space. There's room for two full-size golf bags in the trunk. Still, the motor, power electronics, batteries, and other hybrid accoutrements add about 386 pounds to the standard, V-6 GS sedan, which now weighs in at a hefty 4134 lb.
On the road, you'd likely not notice. Nor are you aware of all the complicated machinations ordered up by the hybrid's computer controllers. "It's a challenge, when you're (switching from electric drive to gas-power) to tell when the engine starts," asserts executive engineer Dave Hermance. After trying, we have to agree.
This is easily the most transparent of any hybrid we've driven. There's very little of that rubber-banding effect you feel in a Prius or RX as the engine revs, seemingly independent of actual road speed. It's even better when you put the shift in manual mode, where it does a reasonable job of emulating a six-speed manual.
Alphabet soup
The '06 GS introduced an alphabet soup of technology designed to improve handling, performance, comfort, and safety. There's a full review on-site, so to keep this piece from stretching on indefinitely, we'll touch on only a few key features, like VGRS, which provides variable gear ratio steering. The steering is electrically assisted.
The Vehicle Dynamics Integrated Management System, or VDIM, takes input from sources like steering angle, yaw rate, brake pressure, and acceleration sensors. That regulates various traction systems, including anti-lock brakes, or ABS, Vehicle Stability Control, or VSC, Traction Control, or TCS, Brake Assist, or BA, and Electronic Throttle Control with intelligence, or ETC-i.
Our test vehicle also included the optional Active Stabilizer Suspension system. (Perhaps you can understand why Lexus uses no acronym here.) It's similar to the BMW system used to variably torque stabilizer bars, but Lexus has gone electric instead of hydraulic.
Toss in the standard rain-sensing wipers, Park Assist, and rearview camera and you've got a car with more silicon and copper circuitry than you'd find at a small Radio Shack. But what happens when it's all running?
While we may be skeptical of the mileage claims, it's hard to fault the performance and pure fun of driving the GS450h. It's smooth and quick and nimble. As with the '06 GS, the steering is precise and quick and the suspension keeps you firmly planted on the road. Better yet, with the electric portion of the drivetrain directly linked to VDIM, the traction systems seem to work just that much more smoothly.
Our complaints, then, are relatively minor. We'd like to replace the mouse-fur headliner, and some of the buttons for the video display are cheap looking. But the display itself is incredible. It's the highest resolution display Lexus has ever offered and that permits a much more detailed, eye-pleasing image, whether you're watching the Hybrid Synergy Drive display or using GPS navigation.
Incidentally, the next-generation nav software now allows you to program street addresses by voice, so you don't have to stop and type - or so we're told. There are no maps for Hawaii , so we couldn't test the claim out.
Expect the powers-that-be at Toyota to be watching quite closely to gauge the reaction to the new GS450h. If things play out well, it's likely to be the first in a series of high-performance hybrids from the Lexus brand. But it could very well kick off a bit of a backlash among those who believe gas-electric technology should be used exclusively to boost mileage.
While we're skeptical of the save-the-earth claims, we're duly impressed with the GS450h's overall performance and handling. It's lavishly equipped and incredibly quiet, as you'd expect from a Lexus, but has a much more sporty feel than the brand has traditionally been known for. We expect a lot of folks to pay attention when the sedan reaches showrooms.
Linear Mode
