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Lexus RX450h

words - Joshua Dowling
Hybrid softroader gets put through a highway challenge
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Lexus RX450h

Road Test

Price Guide (recommended price before dealer and statutory charges): $96,900
Options fitted to test car (not included in above price): nil
Crash rating: not tested
Fuel: 95RON petrol
Claimed fuel economy (L/100km): 6.4
CO2 emissions (g/km): 150
Also consider: Nissan Murano petrol, BMW X5/X6, Mercedes-Benz M-Class, Volkswagen Touareg diesel

Overall rating: 3.5/5.0
Engines and Drivetrain: 3.5/5.0
Price, Packaging and Practicality: 2.5/5.0
Safety: 4.0/5.0
Behind the wheel: 3.5/5.0
X-factor: 2.5/5.0

About our ratings

The Lexus RX450h hybrid is said to be the world's most fuel efficient luxury soft-roader. With an official fuel rating label average of 6.4L/100km it is supposed to sip less fuel than a Toyota Yaris automatic hatchback. It is so efficient; it was the first hybrid vehicle eligible for a Luxury Car Tax exemption.

On the open road, it is said to use just 6.1L/100km according to the Federal Government test. This would be a truly remarkable feat -- if it were true.

To test the theory, we drove an RX450h from Sydney to the Gold Coast in the holiday traffic, except there wasn't too much traffic because we left before the rush. This meant that we were able to maintain a good average speed, just shy of the speed limit in most places with few hold ups.

The open road is not where hybrid cars are typically happiest, because they make most of their fuel savings when driving on electric power in stop-start traffic.

In this case, in addition to the 3.5-litre V6 petrol engine which drives the front wheels, the RX has two electric motors (one that also powers the front wheels, and another which exclusively powers the rear wheels when necessary). And while these electric motors move the car silently at car park speeds they also give the V6 engine a boost when accelerating (Lexus says the total powertrain utput is in the region of 180kW and 320Nm). So the open road is not optimum for hybrids, but Lexus says hybrid power is its answer to diesel; the aim being to deliver diesel-like economy from a petrol engine.

The 1000km (approx) journey was a timely test of the second generation of Lexus' softroader. It also provided us with ample time to get reacquainted with the vehicle six months after its local launch.

With the latest edition, Lexus has mirrored the three model grades that are available in the RX350 V6-only versions. So there are now Prestige ($89,900), Sports ($96,900) and Sports Luxury ($107,900) versions of the hybrid RX. The first two models are $7000 dearer than the non-hybrid versions, but the Sports Luxury has an $11,000 price premium. We had the middle grade Sports version.

There's no doubt the RX is nice place to be. The cabin is opulent. The quality of the materials and the fit and finish are superb. There are plenty of storage pockets, including the air-conditioned centre console, great for stashing treats and drinks on long hauls.

The power tailgate (operated at a press of a button on the remote) is super handy when loading and unloading all the holiday gear and luggage. And the way the steering wheel and driver's seat move into position electrically as you press the ignition are neat.

The silence once you hit the start button can be eerie at first, but you soon get used to its silent running.

Visibility is good, and the rear view is helped by the standard rear camera and large TV screen in the dash.

One notable absence was the lack of a heads-up display that reflects the digital speed in the bottom corner of the windscreen in front of the driver (standard on only the most expensive version). Given that this handy licence saving feature is standard on a $40,000 Prius, it's odd it hasn't found its way on a $100,000 luxury soft-roader.

At least there is radar cruise control to help keep your licence safe. And, helpfully, you can disable the radar function (which maintains a gap between you and the car in front) and use the cruise control normally. I much prefer the old school cruise control as you don't get any false alarms.

It's hard to make such a big blunt object slip through the air at freeway speeds, but Lexus has chiseled away at the shape of the RX and tried to make it as efficient as possible. There is minimal wind noise, in fact you can hear the tyres before you can hear the rush of air past the window.

It steers well and handles itself well in corners despite being up to 150kg heavier than the non hybrid version of the RX and weighing between 2.1 and 2.2 tonnes depending on the model.

The way the headlights follow the direction of the steering (yes, I know, a feature pioneered on old Citroens but we still get excited about it today) makes winding mountain roads less intimidating.

The only question that remained was the fuel consumption. On the first fill, a little past the half way point, the RX450 returned an average of 8.5L/100km. This included about 150km of city driving and 400km of highway driving. On the second fill after arriving in Queensland, it again average 8.5L/100km (this was using our calculations by comparing fuel used with the distance travelled, rather than relying solely on the trip computer -- which also said 8.5L/100km by the way) having done about 500km of highway driving and 100km of suburban driving.

That figure is well short of the 6.4 claimed combined average -- and the 6.1 for the open road. But those figures are derived from lab tests and perhaps don't take into account the level of wind resistance such a big heavy car creates. Nevertheless, 8.5L/100km (driving normally, not for economy) is a respectable number when you consider that's about what a diesel 4WD of the same size would consume. And, on this trip at least, diesel was slightly more expensive than the 95RON premium unleaded the RX450h requires.

The only catch: in order to save about $50 on a fuel bill on a 1000km journey by driving a hybrid RX instead of the petrol-only version, you have to pay a $7000 price premium.

So, to sum up, overall there's not much to not like about the Lexus RX450h, except perhaps the $100,000 price. Indeed, consider this: a Toyota Kluger AWD V6 with the works would set you back about $60,000. That would leave $40,000 left over. Enough spare change to buy a Toyota Prius as well.

And we tested it in town as well... Ken Gratton takes up the tale...

According to the Green Vehicle Guide, the RX 450h should achieve fuel consumption below 7.0L/100km in all three cycles: urban (city), combined and extra-urban.

In practice, as was the case on the open road, the Lexus fell a long way short of the urban cycle figure, 6.6L/100km. Following its previous refill, the trip computer displayed progressively lower fuel consumption figures, falling from 10.1L/100km to a final average figure of 9.2L/100km -- so another week or two of around-town motoring should have reduced the average well below that.

And that's really the point. You can't judge this type of vehicle by its on-paper specs and one's expectations of what it should achieve, necessarily. There's a very strong chance that after six months of nothing more than urban-cycle running, the Lexus could have reached fairly close to that test figure. Anyway, it's not like 9.2L/100km is such a bad figure for a vehicle weighing 2.2 tonnes and only driven in an urban environment.

With the average still on the way down when we handed the vehicle back, there was this consideration uppermost in mind: After a week of traffic, the Lexus had barely used a quarter of a tank of fuel.

And anecdotally, it also felt like the petrol engine was only working 25 per cent of the time. Normally, we'd expect to use three-quarters of a tank in a conventional petrol vehicle of similar size, driven the same way. A diesel would have used perhaps half a tank or less, so the Lexus was impressively frugal -- despite what the average figure suggested -- and taking into further account its performance potential.

Plenty powerful and boosted also by the electric motors, the Atkinson-cycle V6 was smooth and yet muscular-sounding when it was working harder. At other times the Lexus was incredibly quiet, whether or not the V6 was operating, but you could feel when the internal-combustion powerplant kicked in. There was a discernible 'vibey' sense, but the petrol engine was still a very refined unit overall.

But without the power and torque from the petrol engine, the RX 450h -- much like the Prius driven last year -- was not fast when driven on electric power alone. As soon as you required demonstrable acceleration, the V6 cranked up -- but there was less dependence on the fuel tank for energy provision.

"But", you say, "that energy has to come from the burning of petrol sooner or later..." That's true, but the regenerative braking when coasting -- particularly downhill -- offset that to a significant degree. If there were one minor complaint about the regenerative braking, it was the system's occasional lack of progressive retardation, depending on how much or how little power recovery was going on. With consistent pedal pressure, the Lexus would decelerate at faster or slower rates, depending on the amount of power being scavenged from the system.

Tempting as it is to focus on just the RX hybrid's ratio of frugality to performance, it shouldn't be forgotten that it's a good all-rounder. Steering feedback was similar to that of the RX 350, which is to say pretty good for the type of vehicle it is, and the power assistance was very consistent and progressively weighted. The ride was also well controlled; not by any means too soft.

The Lexus was also respectably manoeuvrable in carparks, thanks to a decent field of vision and a nice tight turning circle. Fitted as standard, the reversing camera was well positioned and provided a generally good view to the rear, although the view might have been a bit narrow once the vehicle drew close to an obstacle. That's when the ultrasonic sensors for the acoustic guidance and the animated LED display all came to the party. For a vehicle of reasonable heft and size, the RX 450h was remarkably easy to park.

The driver's position was very easily adjustable to suit a variety of different physiques and the Lexus designers have shown such attention to detail that when the exterior mirrors drop for reversing, they are angled perfectly to observe the rear flanks and wheels of the vehicle as it backs.

You quickly adapt to the whole business of driving the RX 450h and, despite its sophisticated features, the Lexus is a really simple vehicle to just hop in and drive.

Once you find where all the switches are located (HUD adjustment, for example, is on the dash above the knee, to the left of the steering column), the layout is sensible and largely intuitive. There is an economy gauge in the left side of the instrument binnacle, where a tacho would be located in conventional cars. In any other car we'd be in two minds about that, but the way the RX hybrid's V6 develops its torque and power is all mid-range stuff, not top end.

The foot-operated parking brake and hill-start assist combine well. The two features free up space in the centre console for cupholders and a large storage bin. Inside the storage bin, there are two auxiliary power outlets and an input jack for a music source to play through the audio system.

It has to be said, none of these three facilities are easy to reach or connect and, for the money, the Lexus should offer a dedicated iPod/USB input as well as the conventional 3.5mm jack for the Mark Levinson audio system. It's necessary to remove the bin liner to connect anything -- and what do you then do with that liner?

Credit to the good people at Lexus who developed the mouse-like multi-media interface for features like climate control, audio and satellite navigation. The controller is very easy and intuitive to use and frankly, it makes an absolute mockery of certain other systems on the market.

As per our review of the RX 350, the RX 450h is generally well packaged otherwise and there's adult-sized accommodation available in the rear seat as well as the front. For a person of average height, the RX provides straight-in/straight-out access to the cabin. There's no need for contortion to enter the cabin. In fact, you barely need to bend your knees. Some may feel that they need to stoop slightly, seating themselves in the rear. For some reason, the roofline seems a little lower for the rear seats than for the front seats.

There's a space-saver spare tyre to contribute to the car's luggage capacity, although a lot of buyers might expect a little more boot space from a vehicle the size of the RX 450h. Still, the luggage capacity remains quite decent and, unlike the Toyota Prius and the forthcoming Camry Hybrid, the battery pack isn't obvious and intrusive in the Lexus.

The Lexus meets an excellent standard for build quality. Doors are very solid and close with the sort of gravity usually reserved for expensive refrigerators.

On that point, we have to say there's no reason to be ashamed of 'whitegoods engineering' if the end product works that well.

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Published : Tuesday, 2 February 2010

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