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Gas-electric Lexus SUV is quiet, zippy

A test drive of the upcoming Lexus gas-electric SUV found a very quiet ride and quick acceleration, though it also revealed some handling differences.
The 2006 Lexus RX 400h, seen here, looks much like its gas-only RX 330 sibling, but gets much better mileage.
The 2006 Lexus RX 400h, seen here, looks much like its gas-only RX 330 sibling, but gets much better mileage.Lexus/Toyota via AP
/ Source: The Associated Press

The 2006 Lexus RX 400h rolling into showrooms next month isn’t just America's first luxury gas-electric hybrid vehicle.

Filled with soft, leather-trimmed seats, standard navigation system and rearview camera, the RX 400h is an experiment of sorts to see how many affluent car buyers, who usually don't make fuel economy a high priority, will want a high-tech hybrid sport utility vehicle.

Some affluent buyers “want to make a statement about their social consciousness ... that they care (about the world and the environment), but they want to do it without compromising,” said Denny Clements, group vice president and general manager for Lexus, a division of Toyota.

With a starting manufacturers suggested retail price, including destination charge, of $49,185, the RX 400h becomes the latest — and priciest — low-emission, fuel-saving hybrid on the market. The 2005 Honda Accord Hybrid, which starts at $30,505, has been the most-expensive hybrid until now. Other hybrids, including the Toyota Prius, Honda Insight and Ford Explorer Hybrid, are priced in the $20,000 to $29,000 range.

More horsepower than RX 330
The RX 400h looks much like the RX 330 — the mid-sized, five-passenger SUV on which it is based. With sales of more than 106,000 last year, the RX 330 outsells every other Lexus vehicle. But where the RX 330 is powered solely by a 230-horsepower, 3.3-liter, double overhead cam, gasoline V6, the RX 400h has a slightly less-powerful version of this V6 — with 208 horsepower — mated to two motive electric motors that, all together, provide 268 horses.

2006 Lexus RX 400h.
2006 Lexus RX 400h.

One motor up front drives the front wheels; the rear motor powers the rear wheels when needed. The whole process is controlled by a computer as part of Toyota's patented Hybrid Synergy Drive system, which is now in its fourth generation.

Meantime, the RX 330 uses a six-speed automatic, while there is a continuously variable transmission in the RX 400h. The seamless mixing of the power sources as well as the torque is impressive.

On paper, the RX 400h has 212 foot-pounds of torque at 4,400 rpm. But the electric motors deliver the torque from 0 rpm, so the power comes readily and eagerly in the kinds of driving situations that most drivers face every day — accelerating from a stop, merging into traffic and passing other vehicles.

Test drive feedback
In the test drive of the RX 400h, for example, my driving companion got up over the speed limit smoothly, quickly and without realizing it while passing a vehicle on a country road. Indeed, the 0-to-60-mph time of 7.3 seconds reported by Lexus for this hybrid is equal to that of a Mercedes-Benz ML500 SUV with V8.

2006 Lexus RX 400h.
2006 Lexus RX 400h.Toyota via Wieck

But the fuel economy is much better than a V8-powered SUV or even the regular gas-only RX 330. The federal government rating for the 400h hybrid is 31 miles a gallon in city driving and 27 mpg on the highway for a combined rating of 29 mpg. This is higher than the 27.8-mpg average rating for compact sedans and is 38 percent higher than the 21 mpg combined rating for an RX 330 with all-wheel drive.

In addition, the RX 400h puts out fewer pollutants, including 90 percent fewer smog-forming emissions than typical new vehicles. Some of the emissions improvement stems from the fact the RX 400h can drive short distances at slow speed on electric power only, leaving the V6 off.

The engine also can go off on its own at stoplights, where the driver may find himself suddenly enveloped in quiet. When a driver touches the accelerator again, the V6 may start up again to help supplement the electric power. Nothing's wrong. Its just the vehicle's way of being most efficient with its fuel, and it helps explain why the city fuel rating is higher than that for highway travel in this hybrid. On the highway, the gasoline engine has little opportunity to turn off, so more gas is burned.

Nothing to plug in
A driver doesn’t do anything but drive the RX 400h. As with all hybrids, there’s no need to plug in the electric motors. Power for them is generated on-board as the vehicle travels and is stored in a nickel metal hydride battery that fits under the rear seat cushions.

The V6 has a confident sound when it's accelerating and isn’t heard much at other times. I did hear a bit of a “whirring” sound at times in the RX 400h when the electric power was flowing, the radio was off, and there wasn’t much other noise around the vehicle to mask the sound. And, because the RX 400h can be so quiet, I noticed some wind noise emanating from around the side mirrors at highway speeds.

The RX 400h is 375 pounds heavier than its gas-only counterpart, in large part because of the battery pack.

Handling is a bit trickier at the extremes in mountain twisties, because the battery weight makes the vehicle feel as if three fat guys are sitting in the back seat, as one auto writer colorfully put it. But in day-to-day travel, drivers are more likely to notice an occasional lightness to the steering — it's an electric power steering system for energy efficiency.

Not really for off-road
Note that the all-wheel drive is for improved on-road traction and for mild stuff like dirt paths. The hybrid RX is not an SUV for strenuous off-road duty. The reason? The rear electric motor will shut down before it burns itself out in rough situations such as a driver trying to climb over huge rocks or slog through mud.

There are other differences between the RX 330 and the hybrid. Mild styling changes include a revised grille to better channel air for cooling purposes. Taillamps have energy-efficient light-emitting diodes (LEDs).

Since a tachometer doesn’t really provide useful information in a hybrid, where power is mixed and matched among engine and electric motor sources, this gauge is replaced by a power meter in the instrument cluster. And rear seat cushions are positioned a tad higher than in the RX 330, so the hybrids batteries are accommodated.

A large display in the middle of the dashboard can show, via an automated graphic, where the power for the RX 400h is being generated and where it's going as the vehicle travels. It's a similar graphic to the one in the Prius.

Silent startup
The test RX 400h was so quiet at startup, I didn’t always know it was on. This is because the engine doesn’t need to start up right away. This hybrid can go a short distance on oh-so-quiet electric power only. Thank goodness that the RX 400h instrument cluster told me the vehicle was “ready” for driving, so I didn’t just sit there, wondering what to do.

Lexus officials said they could be tapping into an undercurrent of buyers who do not want a big, brutish and flashy SUV that guzzles gasoline, even if they have the money to afford one.

Company officials expect about half of the RX 400h buyers to be women, with the median age of buyers likely to be 45 to 55. Three-quarters will be married, and three-quarters will have a college education. Median household income is expected to be from $150,000 to $200,000 a year.

As of early March, the company had 12,700 pre-sold orders, which accounts for 45 percent of the annual RX 400h allocation of 28,000. “This is significantly more pre-launch volume and activity than we have ever had this early for any vehicle in our 15-year history,” Clements said. Built in Japan, the RX 400h also will be sold in Japan and Europe.

The National Highway Traffic Safety Administration does not have crash test results for this new vehicle. Because the RX 400h is a new model, Consumer Reports does not report a reliability rating.