Lexus RX review - Engines, performance and drive
With a choice of self-charging and plug-in hybrid powertrains, the latest Lexus RX is more refined than ever
The entry-level RX 350h is powered by a 2.5-litre four-cylinder Atkinson-cycle petrol engine that drives the wheels through an e-CVT automatic gearbox, assisted by a pair of electric motors supplied by a small battery. It uses the fourth generation of Toyota and Lexus’s ‘self-charging’ hybrid technology, and many of the components are new, including the car’s hybrid transaxle motor/transmission set-up, which is now more compact and lighter. On the move, however, it feels similar to previous Lexus SUVs fitted with a 350h powertrain.
You’re better off driving to the RX 350h’s strengths, which means being a bit delicate with the throttle to maximise usage of electrical power rather than the engine. This will help the engine settle down, allowing the RX to come across as more refined. The e-CVT gearbox is also at its best when you take a more leisurely approach; cruising around urban areas and on the motorway, the RX feels relaxed and easy-going.
The RX 500h uses a very similar set-up, but under the bonnet is a turbocharged 2.4-litre four-cylinder petrol engine mated to a six-speed automatic gearbox, with one electric motor on each axle, like the 350h. It’s the brand’s first turbocharged hybrid, and it’s smooth rather than sporty but the Direct4 torque-distribution technology (the same as in the all-electric Lexus RZ 450e) does help to keep body roll and pitching in check.
Lexus says the plug-in hybrid RX 450h+ will account for 55 per cent of sales of its large SUV. In this version, the 2.5-litre petrol engine is paired with the two electric motors fed by a considerably larger 18.1kWh battery.
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Much like the 350h, the RX 450h+ has a powertrain that rewards relaxed driving. Mash the throttle and the e-CVT sends the petrol engine’s revs soaring, which quickly becomes a rather unrefined drone. Power delivery is perfectly smooth, even if the performance on tap feels a little underwhelming.
The ride is similarly focused on comfort. Even when riding on 21-inch alloy wheels like our test car, it's obvious the RX has been engineered to float over bumps and dips, rather than communicate the road surface to the driver. It’s not hopeless on twistier toads however, because the steering has a reassuring weight to it and the handling is tightened by the six degrees of rear-axle steering. You’re always aware of the over 2.2-tonne kerbweight, but the RX still flows through corners nicely.
Even though the previous RX was one of the most refined cars in its class, Lexus says it has worked hard on making the latest generation even better in this department. The option of plug-in hybrid power certainly helps, but thicker glass and more soundproofing mean this latest RX is supremely quiet even at motorway speeds.
0-62mph acceleration and top speed
The Lexus RX is hybrid-only in the UK, and every model features a pair of electric motors for four-wheel drive. The 247bhp RX 350h will sprint from 0-62mph in 7.9 seconds and hit a top speed of 124mph. There’s a small boost of torque from the e-motors, but ask for anything more than gentle acceleration and the petrol engine will kick in with an audible drone.
The RX 450h+’s top speed is the same, but a total power output of 304bhp allows it to hit 62mph in 6.5 seconds. You can also drive at up to 84mph on electric power alone in the plug-in hybrid RX, with the instantaneous torque from the electric motors providing some extra pep around town.
Finally, there’s the RX 500h – the quickest of the bunch – with 366bhp on tap, a 0-62mph time of 6.2 seconds and a 130mph top speed. It feels quick enough but it won’t challenge rivals from BMW, Mercedes and Porsche for outright pace. The six-speed automatic is best left to its own devices as the 500h rarely pays attention to the manual shift paddles.
