Review and photos by Greg Wilson

2006 Lexus RX 400h
Click image to enlarge

Despite the rising price of gasoline and mounting evidence that a build-up of carbon-dioxide in the atmosphere is contributing to global warming, most truck and SUV owners are not rushing to their local dealerships to trade in their SUVs for compact cars. Sales of hybrid cars are still a relative drop in the bucket, and even diesels have yet to catch on in North America.

This is particularly true with luxury car buyers who are even less concerned about the cost of gasoline. Lexus’ own research shows that luxury car buyers are not prepared to give up performance, comfort, convenience and safety to save fuel, even if they’re predisposed to buying an environmentally friendly vehicle.

The introduction of a luxury vehicle with the seemingly contradictory qualities of abundant power, four-wheel-drive, luxurious features, a roomy interior AND excellent fuel economy and low emissions would seem to provide the answer for some of the more environmentally-conscious SUV owners.

2006 Lexus RX 400h
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The new 2006 Lexus RX 400h Hybrid, a gas-electric version of the RX 330, offers better fuel economy, fewer harmful exhaust emissions (NOx, HC, CO) and less carbon dioxide ‘greenhouse’ emissions. And to keep those uncompromising luxury car buyers happy, the RX 400h Hybrid actually goes faster in a straight line than an RX 330 and has all the same luxury and safety features available.

It looks like Lexus SUV buyers can have their cake, and eat it too. Well, not quite.

Hybrid fuel consumption varies

The RX 400h’s hybrid powertrain is very sophisticated: its components consist of a 3.3 litre DOHC 24 valve VVTi V6 engine (the same one used in the RX 330), a continuously variable transmission (instead of a 5-speed automatic), two electric motors in front to drive the front wheels and one at the rear for its on-demand electronic 4WD; a powerful nickel metal hydride battery pack, and a computer controller to coordinate the whole works. As well, the RX 400h has electric power steering and electrically powered brakes.

2006 Lexus RX 400h

2006 Lexus RX 400h
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Unlike Honda’s hybrid system which uses a powerful battery and electric motor to assist the gasoline engine but cannot run on the battery alone, Toyota’s system can run on the battery pack alone, the engine alone, or both depending on power requirements. The engine turns on and off automatically at the whim of the computer controller, and it’s almost seamless. When coasting and braking, Toyota’s regenerative braking system recharges the battery. It’s completely self-sustaining and never has to be plugged in.

Obviously, the RX 400h Hybrid gets its best fuel economy when running on the battery alone. This occurs when driving on level ground at low speeds, when coasting downhill at certain speeds, and when stopped at a traffic light. In downtown ‘stop and go’ rush hour traffic, the RX 400h can literally use no fuel at all.

Official fuel consumption figures issued by Natural Resources Canada are City: 7.5 L/100 km (38 mpg Imperial) and Hwy: 8.1 L/100 km (35 mpg Imperial) for an average of 7.8 L/100 km (36 mpg Imperial). The RX 330 is rated at City 12.0 L/100 km (24 mpg Imperial) and Hwy 8.6 L/100 km (33 mpg Imperial), an average of 10.3 L/100 km (27 mpg Imperial).

2006 Lexus RX 400h

2006 Lexus RX 400h
When stopped at a traffic light, the engine shuts off by itself to save gas

2006 Lexus RX 400h
Under light throttle from a dead stop and when travelling at speeds under 30 km/h, the battery alone drives the vehicle

2006 Lexus RX 400h
If the battery needs charging or a little more power is needed, the engine will start up automatically under light throttle

2006 Lexus RX 400h
When braking or slowing down at city speeds, the engine may turn off and the regenerative braking systems recharges the battery

2006 Lexus RX 400h
While cruising at a steady speed on the freeway on a level surface, only the engine powers the vehicle

2006 Lexus RX 400h
Under maximum acceleration, both the engine and battery send power to the driving wheels

2006 Lexus RX 400h
When coasting or braking at freeway speeds, the battery is recharged

2006 Lexus RX 400h
At a steady 100 km/h on the freeway on a level road, the RX400h consumes 10 litres per 10 km of gasoline

2006 Lexus RX 400h
In the centre control panel, this LCD display shows real-time average fuel economy
Click images to enlarge

You can see from these figures that where you drive will make a big difference to your fuel consumption. In city driving, the Hybrid gets 58% better fuel economy than the RX 330, but only about 6% better fuel consumption in highway driving. If you do a lot of highway driving and very little city driving, your fuel savings won’t nearly be so good. In fact, in the week that I drove the RX 400h, my average fuel consumption was 9.8 L/100 km (29 mpg Imperial). However, this is still better than an RX 330 – but not nearly so good as a Toyota Prius which averages 4.1 L/100 km (69 mpg Imperial) according to Natural Resources Canada, but more in real-life driving.

Certainly, by using less gasoline than a conventional SUV, the RX 400h will contribute less pollution and CO2 into the atmosphere. The RX 400h is rated as a Super Ultra-Low Emission Vehicle. But Toyota’s claim that the RX 400h has the same gas mileage as a compact car has to be taken with a grain of salt. Real-world fuel consumption may not be that good. And when compared to hybrid cars, most diesel cars and a lot of small four cylinder compact cars, the RX 400h uses more fuel.


Driving impressions

The surprising thing about the RX 400h is that you don’t have to give up any performance or comfort to get better fuel economy. The combined horsepower rating of the RX 400h’s 3.3 litre V6 and 288 volt battery pack is 268, or 38 more horsepower than the RX 330. The RX 400h has a 0 to 100 km/h time of 7.4 seconds, about half a second quicker than the RX 330. And during my test-drive, I noticed that the RX 400h has exceptional highway passing performance. I was amused to think what other drivers would be thinking when they were passed in solid fashion by a “Hybrid”.

As well, the RX 400h’s towing capacity of 3500 pounds is equal to that of the RX 330.

In the driver’s seat, a round gauge to the left of the speedometer displays how much electrical power the hybrid system is generating in Kilowatts. As well, a small bar graph in the speedometer can be set to show a pictograph of the power transfer between the engine, battery and driving wheels (see photos). It can also be changed to display average fuel consumption and instant fuel consumption. RX 400hs with the optional navigation system have a centre mounted 7-inch colour screen that will show a larger hybrid power transfer diagram.

When you get in and turn the ignition key, nothing happens: at least it seems that way. A small light says ‘Ready’, and you can drive away silently on battery power alone. If the battery needs charging or more power is needed, the 3.3 litre V6 will start automatically – you can hear it start, but it’s very quiet.

When driving on battery power alone, be careful not to creep up on pedestrians who don’t hear you coming, and who may step out in front of the vehicle. My experience driving hybrids and electric cars is that pedestrians often use their ears rather than their eyes to determine if a car is approaching, and may only look at the last second.

At slower speeds, you can drive on battery power alone, but I found the engine starts up with very little provocation. If you have a heavy right foot, the gas engine will be used a lot more. Moderate acceleration uses the 3.3 litre V6 engine alone, but if you’ve got your foot to the floor, both the engine and battery will kick in.

There is no tachometer in the RX 400h, but at cruising speeds the engine is fairly quiet and wind noise is not excessive. At a steady 100 km/h on a level road, fuel consumption is about 10.0 L/100 km (28 mpg Imperial).

2006 Lexus RX 400h
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Because the RX 400h sometimes shuts off the gas engine, the steering, braking and air conditioning systems are electronically-controlled. I found the steering easy to operate and surprisingly responsive, while the ABS-equipped disc brakes with Brake Assist have plenty of power and the air conditioning provided sufficient cooling. The RX 400h is a tall vehicle, but with standard 235/55R-18 inch all-season tires and a fully independent MacPherson strut suspension, it has a good grip on the road and a smooth ride.

My biggest concern with the driving experience is the ‘whine’ from the electric motors as the car slows to a stop. I found it irritating.

The RX 400h has all-wheel-drive, but it is a different system to the RX 330’s. The front wheels are powered by two electric motors, and if they slip, power is transferred electronically to a third electric motor at the rear which drives the rear wheels. This AWD system is designed for light duty, such as gravel country roads, not steep off-road trails.

2006 Lexus RX 400h
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The CVT transmission has a ‘B’ gear in the transmission selector which is a lower gear for going down hills, but it’s not a Low Range gear for off-road driving.
As well, the RX 400h is equipped with Lexus Vehicle Dynamics Integrated Management (VDIM) system, an advanced stability control system which controls understeer and oversteer by automatically braking, accelerating and/or steering. It is designed to enhance the driver’s response rather than override it. I tried this recently on a closed course in a Lexus GS 430, and found that it really did enhance control and safety in emergency situations. If the RX 400h is involved in a rollover, the hybrid system is designed to shut down automatically, a feature which can protect emergency workers from the hybrid’s high voltage system.


Many luxury features standard


2006 Lexus RX 400h
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As I mentioned earlier, RX 400h buyers don’t give up any luxury for better fuel economy. The list of standard equipment includes leather upholstery, aluminum interior trim, 10 way power front seats, heated front seats, dual zone automatic climate control, 6-disc in-dash CD player and cassette and steering wheel controls, 40/20/40 split 2nd row seats, and power everything.
Standard safety features include advanced front airbags, a knee airbag for the driver, side-impact airbags in the front seats, and side curtain airbags.

The only option available is a luxury package ($7,500) which includes a Mark Levinson premium audio system with eleven speakers, 7-inch colour LCD display, DVD based navigation system, rear seat DVD screen and player with wireless headphones and joystick controls.

2006 Lexus RX 400h
Click image to enlarge

The $62,200 base price of the RX 400h is $12,000 more than the RX 330. That’s a lot of change to pay for better fuel economy, more power, larger tires, and a few more luxury and safety features.


Verdict

The Lexus RX 400h Hybrid offers fuel economy gains and emissions reductions when compared with a Lexus RX 330, but they will vary widely depending on where and how the Hybrid is driven. As well, the price premium for the RX 400h is steep.


Technical Data: 2006 Lexus RX400h Hybrid

Base price $62,200
Options None
Freight $1,675
A/C tax $100
Price as tested $63,975 Click here for options, dealer invoice prices and factory incentives
Type 4-door, 5-passenger mid-sized SUV
Layout transverse front engine/electric AWD
Engine 3.3 litre V6, DOHC, 24 valves, VVTi
Electric motors front and rear permanent magnet
Battery 288 watt nickel metal hydride
Horsepower combined 268 @ 5600 rpm
Transmission continuously variable
Tires P235/55R-18
Curb weight 1981 kg (4365 lb.)
Ground clearance 180 mm (7.1 in.)
Towing capacity 1588 kg (3500 lb.)
Payload capacity 420 kg (926 lb.)
Wheelbase 2715 mm (106.9 in.)
Length 4755 mm (187.2 in.)
Width 1845 mm (72.6 in.)
Height 1740 mm (68.5 in.)
Cargo capacity 900 litres (31.9 cu. ft.) behind 2nd row
  2050 litres (72.4 cu. ft.) behind 1st row
Fuel consumption City: 7.5 L/100 km (38 mpg Imperial)
  Hwy: 8.1 L/100 km (35 mpg Imperial)
Warranty 4 yrs/80,000 km
Powertrain Warranty 6 years/110,000 km
Hybrid-related
components warranty
8 yrs/130,000 km

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