WITH its new petrol-electric vehicle, Lexus mounts a serious challenge to competing diesels as the powertrain of choice for luxio SUVs.
The vast shadow cast by a big SUV would usually provoke the wrath and ire of greenies, anti-4WD lobbyists and owners of anything smaller.
But this Lexus is a little different.
The first subtle hint comes from the noise - or lack thereof - as the RX400h silently negotiates the slow traffic without a sound or a particle of CO2. Less subtle are the glaring chrome HYBRID badges that adorn its back and sides.
The launch of this politically correct petrol-electric SUV could not come at a better time for Lexus. While the arrival of the hybrid RX comes an entire year after its launch in the United States, it enters a luxury car market struggling under the social and ethical dilemma of owning of a gas-guzzling, tree-killing SUV.
It also enter the arena at a time of new petrol and diesel offerings from Audi (Q7) and Volvo (XC90). BMW's new generation X5 is just over the horizon.
But the RX is so politically correct, it literally saves trees. Even the wood trim that usually adorns the RX350 Sport Luxury model, on which it is based, has been replaced with a metal finish. Just imagine the opportunities for eco-oneupmanship that this will afford at Birchgrove dinner parties.
The RX400h pairs a 155kW 3.3-litre V6 petrol engine with two electric motors that sit atop the front and rear axles, driving the wheels either with the assistance of the petrol powerplant, or independently when little power is needed for forward motion.
While the pairing of petrol and electricity can propel the SUV from standing to 100km/h in 7.6 seconds, combined fuel consumption is quoted at a mere 8.1 litres per 100km.
Like Lexus's GS450h sedan, the RX400h starts up purely on electric power. While it is disconcerting to start the key and get no aural response, the technology speaks constantly through information screens on the instrument panel and on the sat-nav/DVD info screen.
Even the air-con is run on electric power, and the car is capable of running some distance using purely the 123kW front motor and the 50kW rear motor. The latter is only activated during launch, low-speed corners, and any instance where front-wheel traction is lost.
The E-Four AWD system is predominantly front-drive, with maximum torque split set at 72:28.
When power or acceleration is needed, the petrol engine kicks in to assist the electric motors, splitting its output between powering the front wheels, and feeding the battery for the electric motors.
As both petrol and electricity are constantly working together to generate as well as regenerate power, the combined power of all three motors is a maximum of 200kW (not the sum-total of the 155kW petrol motor and the 123kW and 50kW electric motors - though that would be nice).
Combined with the electronic Continuously Variable Transmission, the generous feed of power results in seamless acceleration and accessible torque that spreads up the speedo like thick cream cheese.
Energy that is usually wasted during deceleration is also utilised with regenerative braking technology. The electric motors take the energy from the wheels and convert it to electricity, recharging the hybrid battery.
This process actually does make a sound - a faint whirring whine that gets louder as the vehicle slows to a stop, and is reminiscent of a sound effect from a B-grade sci-fi flick.
Thankfully, under full throttle, the hybrid acts and sounds like a petrol car, emitting a distinct and sweet-sounding exhaust note. And a petrol engine means petrol bowsers as opposed to the too-often filthy nozzles that plague diesel vehicle owners.
It is yet another plus that may push luxury SUV buyers away from the diesel alternatives, which now claims 30 per cent of the luxury SUV market.
No messy, slippery diesel bowsers or high-flow only service stations. No smell on your hands for days after contact. And a fuel figure that is almost 1.5 litres less than its nearest BMW X5 3.0d and Mercedes-Benz ML320 diesel competitors.
But if you thought a diesel carried a hefty premium over a standard petrol car, the RX400h is $10,000 dearer than the conventionally powered Sport Luxury model on which it is based, pushing the price tag up to $94,100.
This price is only $500 over the diesel ML320 (which now carries a previously optional $8K luxury pack as standard), and $4,600 over the soon-to-be-replaced X5 diesel.
The RX cannot match either for driving dynamics. Even the addition of new active steering has not helped the dead steering feel. And the petrol engine is rather passe.
While the RX400h was in the final stages of testing in Australia (to ensure it could handle our extreme conditions), the 3.3-litre engine in the petrol RX was replaced with a larger and more fuel-efficient 3.5-litre powerplant.
While it hardly affects the Hybrid's performance, it essentially leaves the cutting-edge car with a superseded engine.
That aside, this second hybrid from Lexus will sell, and probably sell well. A big luxury car that carries all the benefits of an SUV without the stigma may well be worth $10K to some, and the petrol-electric premise makes for a strong argument against the diesel competition.
Toyota/Lexus are aiming at 10 million sales by 2010 and expect one million of these projected sales to be hybrid. Looks like the bandwagon is driven by an electric motor.
Samantha Stevens is a roadtester on the CARSguide team. Her work appears here and in the Sunday Telegraph CARSguide. A version of this review, as well as other news, reviews will appear in the Sunday Telegraph.
