Three beating hearts
When it comes to design, comfort, equipment level and workmanship the Lexus RX 450h is certainly comparable with its European rivals. But the model offers a radically different drive technology. Whereas the Europeans are mostly sold with a diesel motorization the Lexus associates an internal combustion power plant with electrical motors.
Although the petrol fuelled RX 350 model has enjoyed hardly any success in Europe it is very different in America. Here it is positioned as the entry level model for the RX range. In the United States those who find the Toyota Prius… the hybrid pioneer… too weak or too small tend to go for the Lexus RX 450h, the top-of-the-range model, even if it is really not much more than an elevated estate car. It has no off-road ambitions at all but this seems not to put off the buyers. However the all-wheel-drive which comes as standard is not all it might be. Unlike the driveline of the RX 350 the hybrid model sees the power for the rear wheels derived from an electric motor at the back producing 68 horsepower (50 kW) and a maximum torque of 139 Nm. The front wheels get their power from a 249 horsepower internal combustion engine with 3.5 litres capacity, but also from a second electric motor contributing 167 horsepower (123 kW). Both electric engines draw their energy from a 288 volt nickel–metal hydride battery pack.
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- The front wheels get their power from a 249 horsepower internal combustion engine with 3.5 litres capacity and also from a second electric motor contributing 167 horsepower. The rear wheels are driven by an electric motor producing 68 horsepower.
299 horses but economical, too
But simple addition does not result in a calculation of total power output. This amounts to 299 horsepower (220 kW) for the 2.2 ton SUV. In fact the hybrid is only 150 kilos heavier than the petrol powered RX 350. When driven slowly… up to 40 kilometres an hours… the Lexus runs on electricity alone. But when serious acceleration is called for the 3.5 litre engine and both AC synchronous electric motors are all on hand to deliver the goods. A hundred kilometres an hour can be reached in a brisk 7.8 seconds although all of the rival models do better in this regard. But with the RX 450h driving dynamics is less important than fuel efficiency. During test driving on the highways of Florida, at constant speeds on the open road or in the city traffic of Miami or Fort Lauderdale the consumption was indeed the stated 6.3 litres of petrol per hundred kilometres driven. After more lively driving this went up to only 7 litres.
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- The power delivery for the Lexus RX 450h is via a step-less CVT transmission. There are few solutions which are more efficient, but many which are better.
The elastic band effect
These are admirable values, achieved in part thanks to the rather unconvincing automatic transmission with its step-less configuration. When fast overtaking is the order of the day the driver hears a scream from the six-cylinder engine and feels not very much of a forward push. The ‘elastic band effect’ associated with CVT (continuously variable) transmissions is even more noticeable in the RX 450h. In truth there are few solutions which are more efficient, but many which are better.
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- The design of the new Lexus RX 450h is little changed and still does not entirely correspond to European tastes.
Above all, comfortable
Ride comfort has been the priority of the Japanese engineers when it comes to the matter of the car’s suspension settings. The springing is soothing although the rear axle can dance around a bit on bad road surfaces. Sudden bumps in the road and transverse joints are a challenge for both springs and dampers. As an option for this luxury Lexus there is electronic damping control and air suspension. The very synthetic Servo steering will fail to please many… not just drivers addicted to dynamics. Feedback from the road surface is poor as is the wheel-return when dealing with roads where there are plenty of bends. Nevertheless for motorists whose main wish is to indulge in leisurely cruising the Lexus is ideal. Such drivers will not be bothered by the rolling motion at higher speeds... the result of the aim to be, above all, comfortable.
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- As is to be expected of a luxury SUV which is 4.77 metres long the Lexus RX 450h has a roomy interior. In front there is generous space in spite of the bulky central tunnel.
Plenty of room but some weak details
As is to be expected of a luxury SUV which is 4.77 metres long the Lexus RX 450h has a roomy interior. In front there is generous space in spite of the bulky and wide central tunnel although the comfy leather seats could offer more cushion depth and lateral support. In the second row the head-rests are much too low and there is a lack in terms of adjustment controls. The RX 450h fails to offer seat heating, two-zone air conditioning or a 220 volt power plug. The DVD entertainment system carries the outrageous price tag of 3,450 Euros. These are weaknesses which are not entirely compensated for by the excellent Mark Levinson audio system and the electrically operated tailgate. This sluggishly opening hatch opens onto space for from 446 to 1,570 litres of load… not a huge cargo carrying capacity but for many buyers quite sufficient.
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- The total power output of the three engines amounts to 299 horsepower (220 kW) for the 2.2 ton SUV. The hybrid is only 150 kilos heavier than the petrol powered RX 350.
Lexus… really the best option?
The Lexus RX 450h is far from being a bargain. The basic price for a version with reasonable level of comfort is 59,950 Euros. A hard-disc based navigation system, electrically operated tailgate, 19 inch rims and reversing camera cost an extra 6,260 Euros. For a further 6,900 Euros the ‘Ambience’ version provides air conditioned seats at the front, a high-end sound system, air suspension and key-less access. Distance-warning cruise control with emergency braking is an extra costing 3,500 Euros and the glass sliding roof panel is another 1,350 Euros. The buyer must come up with 1,450 more for the heads-up display but will still not benefit from overtaking or lane-holding assistant systems, nor fatigue detection or traffic-sign recognition. All of this means that the fully equipped Lexus hybrid will finally cost more than 80 thousand Euros. This is about the same price level as that of well outfitted BMW X5 or Mercedes ML 350 Bluetec models. When the lower re-sale value of the Lexus is taken into to account any advantages resulting from the fuel economy can be forgotten. And the rival models also offer a thousand kilometres range, albeit with higher consumption and a considerably larger fuel tank.
