The sales potential of the RX400h is massive. Target sales in the UK for the remainder of 2005 are 1625. Orders placed in the US alone currently stand at 18,000 and counting. In 2006, the RX400h is expected to account for half of all RXs sold. And when you take a closer look at what you get for your money, it’s hardly surprising.
Three engines for a start. If you think the way the Prius organises its single petrol and single electric motors to achieve the most efficient team effort is a small miracle, the RX400h’s effort amounts to the full parting of the Red Sea number. It employs a 208bhp 3.3-litre V6 petrol engine and not one but two electric motors – a new and impressively brawny 165bhp unit in the front and the Prius’s 66bhp motor at the back, answering the part time 4x4 brief.
But don’t be tempted to add up all the outputs and conclude that the RX400h can call upon 439bhp. It doesn’t work like that. ‘Synergy’ is the key word, here. In normal driving conditions, the petrol engine’s power output is divided by a power-split device, both to drive the wheels directly and also to power a generator which, in turn, drives the electric motors and simultaneously charges the battery beneath the rear seats. The allocation of power is constantly monitored and adjusted between the petrol engine and the motors to maintain the highest efficiency, not the highest output. The best the RX400 can manage is 269bhp. During deceleration and braking, the petrol engine switches off and the electric motors act as high-output generators.
For the driver, things could hardly be simpler. Climb in, twist the key (no starter motor, not much noise of any sort other than a faint background hum), pull the gear selector into Drive and, well, do just that. If you’re fairly gentle with the throttle, you’ll pull away in something approaching eerie silence as, unless the battery reserve is low or you need to blast Tom Hanks in his Prius away from the lights, the RX400h always starts using electric power alone. And it will always return to it whenever possible. When stationary, it shuts down altogether which, of course, is zero emissions in the truest sense. If the Lexus RX weren’t already the quietest SUV on the planet, it is now.
Osamu Sadakata, chief engineer for the RX400h, describes the driving experience in one word: seamless. ‘Every part, every movement must be seamless and the handling so smooth that the driver remains unaware of the sophisticated technology at work. I like to think of it as unnoticed technology’, he says. And he’s right. The biggest contribution to the impression is the way the engines and continuously variable transmission co-operate, not just to make acceleration truly stepless but also to fill in what would otherwise be troughs in the power and torque curves. Perhaps the most startling first impression is what happens when you pull out to overtake. Yes, as your toe goes down, the engine revs flare in the way common to all CVTs but instead of the road speed being slowly dragged up to match, there’s an instant and very solid thump in the back – accompanied by a twitch of torque steer – as the petrol V6’s exertions are manfully assisted by an injection of electrical twisting action.
Lexus’s choice of Greece as a launch venue for the RX400h offers a handy juxtaposition of choked and choking city driving – a legitimate RX400h environment, though it seems unlikely it will qualify for the London congestion charge exemption granted to the Prius – and smooth, snaking coastal roads. At one point, on the journey from Athens to our hotel, we’re overtaken by a Merc SLK 350 in a reasonable hurry. Despite enjoying the scenery and the remarkably hushed, comfortable progress of the Lexus, we decide to be in a reasonable hurry, too. Just to see.