2006 Lexus RX 400h

Vehicle Overview

In April 2005, Toyota's luxury division launched the industry's first upscale sport utility vehicle with a gasoline/electric hybrid powertrain. Introduced at the 2004 North American International Auto Show, the hybrid-powered SUV had first been seen in concept form a year earlier.

Closely related to the gasoline-powered Lexus RX 330, which falls into the midsize luxury SUV segment, the RX 400h gets a new, second-generation version of Hybrid Synergy Drive. As explained by Lexus General Manager Denny Clements, the new battery can deliver twice the power of the battery in a Toyota Prius, as redesigned for 2004. Furthermore, the new electric motor can operate at 12,000 rpm, which is twice the speed of the Prius' motor. Peak output totals 268 horsepower, which is about 20 percent higher than a regular RX 330.

Clements even claimed that the RX 400h would beat the 0-to-60-mph acceleration time of the RX 330, which is under 8 seconds. Performance gains are expected to be even stronger in passing-range acceleration, from 30 to 50 mph, due to the torque burst that the high-output electric motor can deliver. Combined fuel efficiency, Clements said, will be significantly better than the EPA average for four-cylinder compact sedans, with a range between fill-ups of more than 600 miles.

The RX 400h also has earned a SULEV (Super Ultra Low Emissions Vehicle) rating. Clements noted that driving the RX 400h round-trip between Los Angeles and New York nine times would produce fewer smog-forming emissions than painting a room with a gallon of house paint. Mike Wells, vice president of sales and dealer development, said the RX 400h is "a total package that goes beyond fuel economy and low emissions," and is actually "targeted more at performance."

The all-wheel-drive system features a separate rear-wheel-drive electric motor. A new Vehicle Dynamics Integrated Management system combines stability control with new electronic braking technology. Toyota has introduced its own new hybrid-powered SUV: the Highlander Hybrid.

Exterior

The RX 400h's appearance differs only modestly from the regular RX 330. Styling revisions include round fog lamps and an additional opening on the front bumper fascia for cooling powertrain components. The RX 400h is an inch longer than the RX 330 and weighs 300 pounds more.

Interior

The RX 400h's five-passenger seating and interior space are similar to the RX 330's. However, brushed aluminum trim is used only on the RX 400h. Rather than the usual tachometer, the dashboard contains an illuminated battery-power meter. The steering wheel contains controls for the hybrid system's monitor and the stereo.

The backseat has been raised 0.7 inch to accommodate the battery pack underneath. Thirty battery modules are split into three groups, each with a dedicated cooling fan.

Under the Hood

Combining a 208-hp, 3.3-liter V-6 and electric motor-generators, the second-generation Hybrid Synergy Drive powertrain generates 268 hp total. A continuously variable transmission sends that energy to the wheels. The full-hybrid system can operate in gas or electric mode, as well as a combination of both. Lexus says the gas engine starts at a lower power level, which makes the transition between power sources harder to discern. Like the RX 330, the RX 400h can tow up to 3,500 pounds when properly equipped.

Safety

Antilock brakes incorporate electronic brake-force distribution and brake assist. Side curtain-type airbags, seat-mounted side-impact airbags and a driver's knee airbag are installed. An Adaptive Front lighting System can swivel in accord with the front wheels to better light curves in the road.

Driving Impressions

Hybrids might be known for fuel-saving capabilities, but performance reigns supreme in the RX 400h. This SUV zooms confidently and effortlessly from a standstill to highway speed, and it's difficult to discern exactly when the gasoline engine comes into play. Once it does, though, noise from the V-6 is more pronounced than expected from a Lexus, and it quiets down properly at speed.

The ride is pleasant and steering is easy on smooth roads. Bright, recessed gauges are easy to read. You get a full luxury experience, bountiful powertrain response and impressive city fuel-economy figures with this SUV, but the price is hefty.