Review Of 2006 Lexus Rx400h

[Matthew_McNally]

Reviewed hereby Barry Winfield

The Mauna Lani Resort on the Kona Coast of Hawaii’s Big Island has five large solar power systems to augment its supply of electricity from the island’s mostly diesel-generated current. To further minimize its dependence on the grid, the hotel runs 122 solar-charged golf carts on its courses. There is a green-turtle breeding area in the lobby, and small sharks circulate in a shallow pond near the beach. Somebody here clearly believes in conservation, even if the hotel did allow Kevin Costner to stay in one of its most expensive suites for six months while making the box-office bomb Waterworld. Now, there’s a waste of resources.

But what better place could there be for introducing the Lexus RX400h to the press? Here’s a vehicle that exploits Toyota’s ingenious Hybrid Synergy Drive technology to provide high performance and good fuel economy. The RX’s estimated EPA city consumption is 30 mpg. That’s about double the mileage of comparable rivals. (For one, Jeep’s Grand Cherokee 4.7 two-wheel-drive model gets 15 mpg.) Like all of Toyota’s hybrids, the RX400h’s highway fuel economy isn’t quite as good, at 26 mpg, but its combined rate of 28 mpg beats the average for many sedans, including the V-6 Camry.

For a 4580-pound SUV, that’s quite an achievement, particularly when you compare that figure with that of the RX330 sport-ute on which this vehicle is based. Lexus says the RX400h boasts 33-percent-better fuel-consumption performance, yet it outruns the RX330 to 60 mph by 0.9 second and whups it in the quarter-mile by 1.0 second. More thrust on less gas? Now we’re talking. Unfortunately, Lexus trucked the RX400h to our test site and then hauled it away when we were done, so we were not able to obtain our own fuel-economy figures. With the Prius, we averaged 42 mpg, well below the EPA ratings of 59 and 51. Lexus says real-world fuel economy for the RX400h will be much closer to the EPA estimates.

Naturally, this comes at a price—which works out to about four or five grand more than what an RX330 will run you. That’s a lot of gas, even at today’s prices, but when you factor in the extra performance, the environmental awareness you’ll be credited with from the Sierra Club, and the ultra-coolness of powering past onlookers on just the whispering electric propulsion, we think the car will find owners like cops find doughnuts.

There’s another category of owner that will be naturally attracted to the Lexus, and that’s anyone with an appreciation for fine engineering. While sitting and listening to Lexus engineer Dave Hermance describe the RX400h hybrid installation, we couldn’t help thinking that if we had not already become somewhat accustomed to hybrid technology, the amazing level of integration and synergy applied to this vehicle would make rocket science seem simple.

Starting up front, we find a 3MZ-FE 3.3-liter V-6 gasoline engine similar to the one in the RX330, only retuned for this application to an output of 208 horsepower—about 10 percent down on its gasoline-only sibling. Don’t worry about that—there are three electric motor/generators (MGs) lending a hand that supply a peak total of 268 horsepower. A part of the front-drive system, the first device—called MG1 by the Lexus engineers—fires the gas engine when required, acts as a generator when called on to do so, and controls one of two planetary gearsets to vary the relationship between the gas engine and itself.

A bigger, more-powerful 163-hp electric motor (MG2) is connected to the sun gear of the second of the planetary gearsets (dubbed the speed-reduction gearset, which provides the stepless ratio changes across the system’s operating range). This motor abets the V-6 gas engine, adding copious amounts of torque to the front transaxle, but it can also power the car all on its own or act as a generator to replenish the hybrid-drive batteries. The final piece in the puzzle is a beautifully designed multifunctional gear, which essentially hooks the whole front-axle power system together, allowing the various components to act separately or in unison, depending on the judgment of the control computer.

At the rear wheels we find the rear electric motor (MGR), which is hooked directly by gear drive to the rear differential. This one is air- and oil-cooled, since it only functions intermittently (the other MGs are water- and oil-cooled), and it adds another 67 horsepower to the mix. Hermance says this motor cranks over 650 pound-feet of drive-axle torque to the vehicle’s overall tractive effort when it’s energized.

0503_rx400_engine.jpgWe believe him. Nail the RX400h’s throttle from rest, and you might hear front or rear tires chirping, depending on available grip. The V-6 growls with the usual determination when you’re hard on the gas, but the continuously variable transmission pegs its rotational speed somewhere near the torque peak and maximum volumetric efficiency, producing sound effects that are the opposite of a slipping clutch. Instead of a rising engine note as vehicle speed remains constant, the vehicle speed rises as the engine speed remains constant.

This understates the RX’s performance somewhat and renders a tachometer obsolete. Instead, there’s a power meter, showing how much draw your right foot is producing in the hybrid system. After driving about in this extraordinary vehicle for a while, two things happen. One is that the RX400h assumes a degree of normality and transparency that plays down the remarkable technology operating behind the scenes. The other is that a driver begins to realize that his or her control is restricted to directional and accelerative inputs.

Important tasks, to be sure, but all aspects of the powertrain management are competently handled by electronic geniuses that decide how much electric assist you can have, how much power is to be bled off the V-6 for recharging purposes, even whether the gas motor is to be used at all. At the day’s first startup, as the driver twists the key to boot up the car, the computer usually fires the gas engine to get some heat into its lubricant. (There is no Thermos-like coolant reservoir in the RX as there is in Toyota’s Prius.)

Thereafter, the system might move the car—particularly at low maneuvering speeds—on electric power alone. Watching the car inch silently up the ramp onto its transporter after our high-desert performance tests was an eerie experience. Yet the RX400h provides more of a conventional experience than the Prius. For one thing, it’s fast. For another, it uses its gas engine to much greater effect in everyday driving. And that was the intent from the outset with this project. The Lexus uses hybrid technology to expand both its performance and efficiency parameters, not just to turn it into a model of miserly motoring.

That means it can handle protracted high-performance driving better than the Prius. The Achilles’ heel of all hybrids is the rapid exhaustion of the battery pack, meaning that an assault on the mountains is exhilarating for five minutes, then you’re dragging the batteries and generators around on the gas engine alone. In the Lexus, you always have 208 horsepower at your disposal. That helps.

In normal driving situations, hybrid systems such as this one work perfectly well because the performance envelope is so generous. Most of the time you are not exploiting all the available power, and there is almost always a downgrade or a need to brake on your route—providing opportunities for regeneration. Lexus likes to keep the nickel-metal hydride cells charged somewhere between 60 and 95 percent in the interests of long battery life, but this limited charge/recharge range seems to make little impact on actual operating efficiencies.

Other than the strange engine cadence and the occasional whir of the electric power steering (which idles until you need it), the driving experience is much the same as that of a conventional RX330. The creature comforts and amenities are about the same, too. The climate-control system uses an electrically powered compressor but is otherwise unremarkable, and the usual array of high-end stereo options, rear-seat DVD entertainment, and power-adjustable gadgets meets the standards for a luxury SUV in exactly the same way they do in a gas-powered Lexus.

And that’s the beauty of this hybrid system. It calls for no more sacrifice from its owner than does a conventional vehicle. You may find yourself watching the gauges to maximize efficiencies, but you don’t have to. Go ahead, have fun. The RX400h does the rest.

2006 LEXUS RX400h

0503_rx400_front.jpgVehicle type: front-engine with rear assist motor, 4-wheel-drive, 5-passenger, 5-door wagon

Estimated price as tested: $45,000 (estimated base price: $45,000)

Major standard accessories: power windows, seats, locks, and sunroof; remote locking; A/C; cruise control; tilting and telescoping steering wheel; rear defroster and wiper

Sound system: Toyota AM-FM radio/cassette/CD changer, 8 speakers

ENGINE

Type: V-6, aluminum block and heads

Bore x stroke: 3.62 x 3.27 in, 92.0 x 83.0mm

Displacement: 202 cu in, 3311cc

Compression ratio: 10.8:1

Fuel-delivery system: port injection

Valve gear: chain-and-gear-driven double overhead cams, 4 valves per cylinder, hydraulic lifters, variable intake-valve timing

Power (SAE net): 208 bhp @ 5600 rpm

Torque (SAE net): 212 lb-ft @ 4400 rpm

Maximum: engine speed 5600 rpm

ELECTRIC MOTORS

Front transaxle

Type: 3-phase AC permanent-magnet synchronous motor powered by 30 9.6-volt nickel-metal hydride batteries

Power (SAE net): 165 bhp @ 4500 rpm

Torque (SAE net): 262 lb-ft @ 0–1500 rpm

Rear transaxle

Type: 3-phase AC permanent-magnet synchronous motor powered by 30 9.6-volt nickel-metal hydride batteries

Power (SAE net): 67 bhp @ 4610 rpm

Torque (SAE net): 96 lb-ft @ 0–610 rpm

DRIVETRAIN

Transmission: continuously variable automatic

Final-drive ratio: 3.54:1

4-wheel-drive system: part time with automatic rear electric-motor engagement

DIMENSIONS

Wheelbase: 106.9 in

Track, front/rear: 62.0/61.2 in

Length/width/height: 187.2/72.6/66.3 in

Ground clearance: 7.1 in

Drag area, Cd (0.35) x frontal area (29.8 sq ft, est): 10.4 sq ft

Curb weight: 4580 lb

Weight distribution, F/R: 55.9/44.1%

Curb weight per horsepower: 17.1 lb

Fuel capacity: 17.2 gal

CHASSIS/BODY

Type: unit construction

Body material: welded steel stampings

INTERIOR

SAE volume, front seat: 56 cu ft

rear seat: 46 cu ft

cargo, seats up/down: 38/84 cu ft

Practical cargo room, length of pipe: 131.0 in

Front-seat adjustments: fore-and-aft, seatback angle, front height, rear height, lumbar support

Restraint systems, front: manual 3-point belts; driver and passenger front, side, and curtain airbags; driver only: knee airbag

rear: manual 3-point belts, curtain airbags

SUSPENSION

Front: ind, strut located by a control arm, coil springs, anti-roll bar

Rear: ind, strut located by 1 trailing link and 2 lateral links per side, coil springs, anti-roll bar

STEERING

Type: rack-and-pinion with electric power assist

Steering ratio: 15.6:1

Turns lock-to-lock: 2.9

Turning circle curb-to-curb: 37.4 ft

BRAKES

Type: regenerative electric and electrohydraulic by wire

Front: 12.6 x 1.1-in vented disc

Rear: 11.3 x 0.4-in disc

WHEELS AND TIRES

Wheel size/type: 7.0 x 18 in/cast aluminum

Tires: Goodyear Eagle RS-A, 235/55R-18 99H M+S

Test inflation pressures, F/R: 30/30 psi

Spare: full size on matching aluminum wheel

C/D TEST RESULTS

0503_rx400_radio.jpgACCELERATION Seconds

Zero to 30 mph: 2.5

40 mph: 3.7

50 mph: 5.2

60 mph: 6.9

70 mph: 8.9

80 mph: 11.5

90 mph: 14.6

100 mph: 16.7

110 mph: 21.9

Street start, 5–60 mph: 7.0

Top-gear acceleration, 30–50 mph 3.3

50–70 mph: 3.5

Standing 1/4-mile: 15.2 sec @ 93 mph

Top speed (governor limited): 112 mph

BRAKING

70–0 mph @ impending lockup: 200 ft

HANDLING

Roadholding, 300-ft-dia skidpad: 0.76 g

Understeer: minimal moderate excessive

FUEL ECONOMY

EPA city driving: 30 mpg

EPA highway driving: 26 mpg

INTERIOR SOUND LEVEL

Idle, gas engine/standby: 40/29 dBA

Full-throttle acceleration: 72 dBA

70-mph cruising: 68 dBA

[RX400h]

Ahhhh, I LIKE that 0-60 time - matches a BMW X5 and gets TWICE the fuel milage as the Bimmer! THATSA technology....

[KevinK]

I am not sure that it worths the extra $8000.

[SW03ES]

You should READ the article ;)

which works out to about four or five grand more than what an RX330 will run you

Who said anything about 8k?

[patt]

Who said anything about 8k?

←

The MSRP of the 400h is 4 or 5 K above the MSRP of a similarly equipped RX330. Since at least during the first year one is likely to pay MSRP for the 400h and one can buy an RX 330 below MSRP, the actual price difference probably comes to 7 or 8 K for someone who does well at negotiation of RX 330 price.

I think the performance, features, and fuel savings are worth it, but I can see where others might not.

[RX400h]

Now I'll bet that if you bought the 400h in April and for some reason had to sell it in November, you'd get pretty close to the MSRP. However, try the same thing with the 330 and you're likely to be out $5,000 or more. Until something better comes along, the resale value of the 400 will be extremely high for years to come.

Another thing that is worth big bucks to most folks is the 650 lbs-ft of Torque that is available at very low rpm. This is more than twice that of the 330! That kind of rocket-power is very valuable, even in day-to-day driving. Add the extra sound-proofing and you've got a heckuva lot of vehicle, even for 50K.

[KevinK]

Now I'll bet that if you bought the 400h in April and for some reason had to sell it in November, you'd get pretty close to the MSRP. However, try the same thing with the 330 and you're likely to be out $5,000 or more. Until something better comes along, the resale value of the 400 will be extremely high for years to come.

Another thing that is worth big bucks to most folks is the 650 lbs-ft of Torque that is available at very low rpm. This is more than twice that of the 330! That kind of rocket-power is very valuable, even in day-to-day driving. Add the extra sound-proofing and you've got a heckuva lot of vehicle, even for 50K.

←

I am afraid that you are dreaming. Any new car will lose 10% or more of the its value as soon as it leave the dealer lot. For hybrid, it loses more, bcs the the used car buyer will not have the one time tax benefit.

[RX400h]

Now I'll bet that if you bought the 400h in April and for some reason had to sell it in November, you'd get pretty close to the MSRP. However, try the same thing with the 330 and you're likely to be out $5,000 or more. Until something better comes along, the resale value of the 400 will be extremely high for years to come.

Another thing that is worth big bucks to most folks is the 650 lbs-ft of Torque that is available at very low rpm. This is more than twice that of the 330! That kind of rocket-power is very valuable, even in day-to-day driving. Add the extra sound-proofing and you've got a heckuva lot of vehicle, even for 50K.

←

I am afraid that you are dreaming. Any new car will lose 10% or more of the its value as soon as it leave the dealer lot. For hybrid, it loses more, bcs the the used car buyer will not have the one time tax benefit.

←

...not around here - a used Prius, if you can find one, will cost you very close to MSRP. The same held true for the PT Cruiser a few years ago when dealers were marking up every one by thousands of dollars. Those fortunate enough to pay MSRP could turn around and sell at a profit. This is what we call "Supply and Demand". It happens all the time and the RX400h will be in SHORT supply and High demand for some time to come.

[SW03ES]

Kevin-

RX4 is right, for a while you could buy a Prius for MSRP, turn around and sell it used for a profit. Some people were selling Priuses with a couple k miles on them for as much as $10,000 above the list price.

The RX isn't going to be quite as in ravenous demand but its going to be the highest demand vehicle Lexus has ever had no question. You wont see one on the lot for at least a year.

[cruznroadking]

I understand that most dealers have taken enough orders to sell out for the first 2 years. Like you said, supply & demand.

[juicius]

Now I'll bet that if you bought the 400h in April and for some reason had to sell it in November, you'd get pretty close to the MSRP. [...]

I am afraid that you are dreaming. Any new car will lose 10% or more of the its value as soon as it leave the dealer lot. For hybrid, it loses more, bcs the the used car buyer will not have the one time tax benefit.

I don't have a 400h sales experience but I just sold my 07 Camry hybrid. I purchased it for a hair under $26000 and after 18 months and 22K miles, sold it for $24500. Not bad, especially considering the tax credit I got. While I agree the immediate drop in value in any new car cannot be avoided, ever increasing gas price does ameliorate it to a large degree if you have the right car. And for now, right car seems to be a hybrid.