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Hybrid gas-electric cars started out as compacts designed to get a gazillion
miles to the gallon. That picture is changing and so must our thinking. Witness
the new 2006 Lexus RX 400h.
The RX 400h boasts all the advantages of a hybrid gas-electric vehicle:
Emissions are extremely low, reducing your impact on the environment. And it
burns about as much gas as a compact car, helping to reduce America's dependence
on foreign oil.
But it's fast. Stomp on the gas and the RX 400h jumps off the line significantly
quicker than the regular RX 330. It can go head-to-head with a V8-powered
Mercedes ML500.
And it's a luxury SUV, loaded with power-hungry features: dual-zone climate
control, GPS navigation, power seats, power windows, a power rear door,
available rear-seat DVD, an optional megawatt audio system by Mark Levinson®.
You can run all that stuff at the same time without any fears of draining the
battery.
And no, you do not plug this car in to recharge it. There is no electrical cord
dangling from the grille, no need to look for recharging stations. Living with
it is quite similar to living with a regular car. Like other gas-electric
hybrids, the RX 400h recharges its battery packs as you drive. The gas engine
helps propel the car and recharges the battery.
The RX 400h combines a regular 3.3-liter V6 gasoline engine with one high-torque
electric drive motor-generator driving the front wheels and another one driving
the rear wheels. It uses a planetary gearset and generator to help route power
to the motors and recharge the batteries. It sounds complicated and we haven't
even discussed the all-wheel drive, the elaborate stability control and
electronic brake system. The more you study it the more you realize its
complexity.
But it's easy to drive. It isn't all that different from driving a regular RX
330 with one major exception: The RX 400h is considered a full hybrid. Most of
the time, it uses a combination of the V6 and electric motors. But in certain
conditions it will run strictly off the V6 engine. In other situations it will
run strictly off the electric motors. Gliding around silently in parking lots
and heavy traffic is a different sensation that's quite enjoyable. Also
enjoyable is the performance. Step on the gas and RX 400h takes off with
enthusiasm.
The RX 400h offers the same 3,500-pound towing capacity as the RX 330, attesting
to its capability. The electric motors should work well in the Rocky Mountain
states because high elevations don't drag batteries down the way they do gas
engines. But RX 400h drivers should stick to the pavement. Batteries are no
match for boulders.
This vehicle is an amazing piece of technology and an interesting vehicle. It's
also complex. To quell concerns about reliability Lexus warrantees the hybrid
drivetrain for 8 years or 100,000 miles. The RX 400h should hold its value well
if the Prius is any indication; 2003 Prius models have held their value even
better than Camry and Corolla.
Model Lineup
The 2006 Lexus RX 400h comes as one well-equipped model. It is the premium model
in the RX series, adding numerous standard features that are offered as options
on the RX 330. The RX 400h comes standard with electric all-wheel drive and all
the powertrain features mentioned in this article.
The list of standard features is long: Regency leather interior trim, automatic
dual-zone climate control, premium audio, cruise control, automatic HID
headlamps with Adaptive Front Lighting System (AFS), 10-way power driver's seat,
eight-way power front passenger's, a leather- and aluminum-trimmed interior,
AM/FM/cassette/six-CD stereo, a power rear door and voice-activated DVD
navigation with Bluetooth® technology and backup camera.
Options include Mark Levinson premium audio with 11 speakers, adjustable front
seat heaters and DVD rear-seat entertainment.
Safety features include side curtain airbags designed to help protect the head
of front and rear outboard occupants in certain types of severe side impacts.
Other supplemental restraint systems include advanced front airbags for the
driver and passenger, a knee airbag for the driver, and side-impact airbags
mounted in the front seats that are designed to protect the torso, abdomen and
pelvis. The hybrid system is designed to shut down whenever sensors detect a
roll to reduce concerns from emergency crews about high-voltage power. All-wheel
drive and the sophisticated electronic stability control system (Vehicle
Dynamics Integrated Management system) are standard, which integrates anti-lock
brakes, Brake Assist and Traction Control. The Adaptive Front Lighting System
aims the High-Intensity Discharge headlamps to illuminate corners as the driver
steers into them.
Exterior Features
The RX 400h and the RX 330 look more alike than different, but there are some
subtle styling differences. Among them: a new front bumper for increased
cooling, a new grille, new foglamps, new taillamps with LEDs instead of
traditional incandescent bulbs.
The RX 400h also gets specific 18-inch wheels. The wheels are 7-inches wide and
the tires are designed to help provide grip in corners rather than offer low
levels of rolling resistance. This says a lot about the intent of the RX 400h.
Lexus could have improved fuel efficiency further with hard, low-grip tires, but
chose to enhance handling instead.
The RX 400h uses an advanced Lexus hybrid system. Two electric-drive motors draw
on 30 modules of nickel metal-hydride (Ni-MH) batteries. Clever engineering has
resulted in efficient packaging of the batteries, which are split into three
groups housed largely under the rear seats.
The hybrid powertrain adds just 300 pounds to the curb weight. That's not an
insignificant amount of weight, but it's an impressive engineering achievement,
and most of the weight is mounted low in the vehicle. Lexus increased the
rigidity of the chassis to manage the additional mass. The Lexus RX and Toyota
Highlander models are built on the same platform (with modifications) as the
Toyota Camry and Lexus ES 330 sedans.
Interior Features
The RX 400h offers the same high levels of comfort found in the RX 330 plus a
few notable additions. Brushed-aluminum accents lend a contemporary look. Also,
the instruments have evolved: In place of a traditional tachometer, there's an
illuminated meter on the left that displays the level of power generated by the
hybrid powertrain. The driver can also monitor the gas-electric power
distribution on the multi-information display or on the navigation system's
seven-inch touchscreen panel display.
The cabin is luxurious and inviting. The leather is soft and slightly bunched.
Getting in is easy, with no need to either climb up or duck down. The front
seats are positioned off the floor at a comfortable chair height and are snug
and supportive. Foldable armrests on both front seats provide additional comfort
on longer trips. The center console slides forward and back, allowing room for a
purse between the front seats.
The instrument panel has three large round gauges. The center dash area is
framed in metallic-looking plastic topped with a pair of air vents. The center
stack is dominated by the seven-inch display. This screen is used for climate
control and trip computer functions, as well as displaying the outside
temperature and clock (with alarm). It's also used by the navigation system and
backup camera. The camera is automatically activated when the transmission is
shifted into reverse. You can't drive backward by watching the screen, but it's
very useful for checking for obstacles that are difficult to see from the
driver's seat. The system includes Bluetooth and voice activation. The downside
to all this integration is that you have to press two buttons to change the fan
speed rather than one. Also, the trip odometer is hard to read. Lexus dealers
can program the default settings of many of the functions, so be sure you have
them tailor automatic door locking and other features to your preferences.
Audio controls are at the bottom of the center stack. The radio has big knobs
for volume and tuning, that are easy to use. The Lexus premium audio is a
132-watt, eight-speaker system with AM/FM/cassette with six-disc in-dash CD
changer. The optional Mark Levinson audio system features 11 speakers and 210
watts.
The shifter for the Electronically-controlled Continuously Variable Transmission
(ECVT) is located on the center dash and follows a mechanical zigzag pattern to
make sure you only move it one position at a time. We found it made shifting
between reverse, drive and the lower gears ponderous when we were in a hurry.
The rear seat is contoured for two, though it has belts for three. There's a
folding center armrest with cupholders and storage. The rear seats fold forward
40-20-40, the center section providing a long, narrow space for skis, shovels
and fly rods, while still allowing four people to ride in comfort. There is no
third-row seat for the RX.
Folding the rear seats down reveals 84.7 cubic feet of cargo space, more than a
BMW X5, Mercedes ML350 or Infiniti FX. The rear seats don't fold perfectly flat,
however.
Driving Impressions
Driving the Lexus RX 400h is quite similar to driving the RX 330. It's smooth
and sophisticated, powerful and responsive. Starting out is a bit different,
however.
Twist the key and everything on the dash lights up, but there's no sound of an
engine starting, only silence. Slide the transmission lever to drive and you can
pull silently away on electric power. This is not at all intuitive at first
because we're all accustomed to hearing and feeling an engine running before
shifting into drive. Shifting into drive when there's no sound, no vibration is
a new experience.
At low speeds, the RX 400h is perfectly content to operate in electric-only
mode. It's quiet, and you begin to hear things that are normally drowned out by
an engine. We found this interesting and enjoyable. It will run in this silent
mode in stop-and-go commuter traffic, eliminating the noise and pollution that
the cars around you are putting out. The RX 400h maneuvers silently through
crowded parking lots as well, where pedestrians often will not hear you coming
and therefore, you should drive cautiously. Lexus' hybrid system uses
electric-drive motors and a gas engine as equal partners, while Honda's system
is a gas engine assisted by an electric motor.
The gas engine starts whenever it's needed to supplement the electric motor.
Step hard on the gas pedal and the V6 kicks in quickly and seamlessly. You can
barely hear or feel when this happens. It works exceptionally well. All the
components work in concert most of the time.
The 3.3-liter V6 is basically the same engine as the one used in the RX 330, but
it's modified and tuned to work with the electric motor. It's set up for the
on-demand instant restarting used by the hybrid system. There's no starter, no
alternator, and no serpentine belt to run all that stuff.
The RX 400h will likely enjoy over a 60-percent edge in fuel efficiency ratings
over the RX 330 in the EPA's city rating, with an EPA-estimated rating of 31/27
mpg City/Highway. Its estimated 29 mpg EPA Combined rating is comparable to that
of the average compact sedan (27.6 mpg); average for SUVs in this class is 15.1
mpg. Lexus says fuel economy is seldom an important consideration for SUV
shoppers but that many buyers later become unhappy with the thirstiness of their
SUVs after owning them.
More impressive is the near absence of environmentally harmful emissions. The RX
400h is rated as a Super Ultra-Low Emission Vehicle in California or Tier 2, Bin
3 in other states, confusing designations that describe some of the most
stringent emissions ratings in the industry.
But what surprised and delighted us was the acceleration performance of the RX
400h. Stand on the gas and it takes off quickly, whether from a standstill or
when cruising. Lexus says the RX 400h can accelerate from 0-60 mph in 7.3
seconds. That's a half-second quicker than an RX 330 and comparable to the
Mercedes ML500, which uses a thirsty V8.
The RX 400h cruises happily at speed out on the highway and there's plenty of
reserve power on tap. When we caught a slower car on a two-lane road, we checked
to see it was clear, pressed the accelerator to the floor, and were able to make
a quick and easy pass. Safe, quick passing performance was important on Hawaii's
Big Island where passing opportunities were limited. Lexus estimates the RX 400h
takes just 3.4 seconds to accelerate from 30 to 50 mph, at least a solid second
quicker than the competition. We were sometimes able to catch the system off
guard, however. While coasting down a hill we suddenly nailed the throttle, not
a move the car seemed to expect, and there was a momentary lag before the power
kicked in. For the most part, though, the RX 400h drives like a powerful and
sophisticated SUV.
If we were to nitpick, we'd say it drones a little under light throttle and the
sound it makes under acceleration isn't entirely pleasing. Also, there's a small
amount of torque steer, or something that feels similar to torque steer: Pull up
to a stop sign, stand on the gas and make a right turn, and you'll feel a slight
tug on the steering wheel or a resistance to turning. But all this amounts to
nitpicking and the description of it sounds much worse than the reality.
The RX 400h glides along like it's on a cloud on smooth pavement. The ride is
firm but damped. You know when you're on a rough road but the ride is not harsh.
The electric steering works perfectly. The steering system uses electrical
signals rather than hydraulic fluid and is speed-sensitive, boosting power
assist at low speeds for effortless parking.
The RX 400h was not designed for serious off-road use. The regular RX 330 isn't
exactly an off-road vehicle, either, but it handles gravel roads just fine. RX
400h drivers, on the other hand, should stick to the pavement or risk damaging
the hybrid drivetrain.
The electronically controlled all-wheel-drive system works very well on slippery
surfaces, however. One of the three electric motor generators (known as MGR)
drives the rear wheels whenever they're needed to help improve traction.
The RX 400h also boasts a new generation of vehicle stability systems that are
as complex as the gas-electric drivetrain. Vehicle Dynamics Integrated
Management, or VDIM, goes well beyond conventional traction and stability
controls that simply react to challenging conditions. Instead, VDIM anticipates
loss of vehicle control and seamlessly makes corrections to help correct the
handling. At the same time, it allows the RX 400h to achieve higher dynamic
capabilities.
For the most part the brakes feel normal. That's impressive given that every
time you use the brakes they generate power. Unless someone had told us, we
never would have been aware that regenerative braking was being used to recharge
the batteries every time we stepped on the brake pedal. That's an improvement
over the earliest hybrid cars, which have an unusual feel to the brakes.
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