If we follow the badge logic, the Lexus RX450h should provide performance equivalent to that of a 4.5-litre V8 rather than the 3.5-litre V6 actually under the bonnet. With the Lexus’s total output of 295bhp, that claim looks a little doubtful next to the V8-powered X5, Mercedes-Benz ML, Range Rover and Porsche Cayenne, which each have at least 350bhp and some considerably more. And sure enough, our recorded 0-60mph time of 8.2sec confirms that the RX450h simply doesn’t have the performance to compete with the most sporting SUVs.
A fairer comparison is with the Volvo XC90 V8 and diesel rivals. The bottom line is that for the majority of driving the RX responds more than quickly enough for most people’s needs. Be gentle on the throttle when pulling away and the RX450h will move off under electric power only, and with sufficient juice in the batteries and a gentle foot it calls on the petrol motor only when speeds exceed 30mph. Ask for a more urgent getaway and the petrol motor kicks in earlier, and if you extend the throttle fully the rear motor lends a hand to give a turn of speed beyond what you could normally expect of a 3.5-litre V6 hauling a 2.1-tonne car.
Other than boosting performance and fuel economy, the electric motors also allow hushed progress at slow speeds, but even with the petrol motor working the RX450h is impressively quiet, registering just 63dB at 70mph. Only under prolonged full throttle, with the CVT transmission holding the engine at high revs, does the RX sound stressed.