Diesel power is out for Lexus – even in Europe – so its riposte to the economical mid-sized oil-burners from German luxury car rivals is the Lexus IS300h.
Hybrids are available in most other Lexus models, including the RX SUV, GS sedan and LS limo, but the IS300h is the first petrol-electric model to be offered in an IS model, which is now into its third generation since 1998.
Its status as the freshest variant of the all-new Lexus IS is elevated by the fact the IS250 and IS350 models both carry over their engines from the previous-generation released in 2005.
The Lexus IS250 sticks with a 2.5-litre V6 now a decade old, and the Lexus IS350 continues with a 3.5-litre vee-configured six-cylinder that at least swaps from the former six-speed auto to a new eight-speed auto.
The IS300h edges ahead of the IS250 in the power stakes – with 164kW produced collaboratively by a 2.5-litre four-cylinder ‘Atkinson cycle’ petrol engine and a single, rear-mounted electric motor.
That leaves the IS350 as the kilowatts leader, with 233kW.
Both the Lexus IS250 and Lexus IS350 are relatively thirsty for the segment, however. The smaller V6 model officially consumes 9.2 litres per 100km, with the bigger-capacity V6 closer to double figures at 9.7L/100km.
This is where the IS300h steps in.
Its efficient hybrid drivetrain brings consumption below 5.0L/100km at 4.9L/100km, with CO2 emissions of 113 grams per kilometre notably better than the IS250’s 213g/km figure and half the IS350’s 225g/km.
On paper, that puts the Lexus IS300h ahead of the most economical Benz C-Class (the 5.4L/100km C200 CDI) and in touching distance of the most frugal German diesel auto competitors – the 4.8L/100km Audi A4 2.0 TDI and benchmark 4.7L/100km BMW 318d (which drops further to 4.5L/100km with a manual gearbox).
Can the IS300h driving experience, however, match the renowned torque-driven driveability of the diesel-powered Germans?
The short answer is no. The slightly longer answer is that it lacks both the effortless throttle pick-up and mid-range oomph of, say, a BMW 320d.
The hybrid’s economy advantage slips out of the city as well, with our trip computer reading 9.2 and 9.3L/100km on two separate stints that mixed town, country and spirited driving. We’d expect diesels to be lower over the same routes, but the IS300h would have the advantage in cities and towns.
Even four-cylinder diesels from the Germans, especially Mercedes, aren’t that quiet, however, and at low speeds or light throttle the IS300h offers a hushed experience.
Refinement would be even better, however, if it weren’t for the characteristic drone of the drivetrain’s continuously variable transmission (CVT) that imitates a slipping manual gearbox clutch.
Drivers can flick a button on the dash to activate a so-called Active Sound Control speaker, attached to the firewall, that emits a sound mimicking engine induction noise.
It helps to mask some of the drone, though it can also be a slightly surreal experience because the amount of noise coming from the ASC doesn’t always correlate with the actual road speed.
The Lexus IS300h still provides smooth progress, though, and is capable of decent open-road space without offering accelerative excitement.
It’s also well balanced on winding country roads, and the steering is accurate, though this is not the IS variant that can challenge a 3 Series for dynamic honours. (An F Sport grade brings a sportier, variable suspension, which we didn’t get to test.)
The IS300h feels its extra weight over the petrol V6 models, and a brake pedal that – as is common to hybrids with regenerative braking – is overly firm and sensitive.
Ride quality isn’t in graceful Lexus tradition of old, either. A generally firm suspension set-up combines with the stiffer sidewalls of the run-flat tyres used exclusively on the hybrid variant of IS – to help create more boot space – to bring a busy behaviour to proceedings.
A comfortable driving position, however, is afforded by a multi-adjustable (electrically in F Sport and Sports Luxury grades) steering wheel and low-set seat.
Lexus has also successfully shrunken the interior design of the bigger Lexus GS for the new IS.
The bamboo trim of one IS300h Luxury model we tested certainly helped lift the cabin image beyond that of a mere base model – or one the could be linked with a product from parent company Toyota.
As we’ve come to expect from Lexus vehicles, options lists are short and standard equipment columns are long.
Lexus’s Remote Touch makes its debut in the IS. The computer-mouse-aping controller on the centre console offers an alternative to touchscreens or similar menu-operating systems from other makes, though the joystick can still be a touch sensitive and overall it doesn’t feel as sophisticated or intuitive as BMW’s iDrive or Audi’s MMI.
Out back, the 2013 Lexus IS addresses a key flaw of its predecessor to take on its German rivals in rear seat legroom.
Lexus has increased the IS’s wheelbase by 70mm in a body now 75mm longer, using 50mm of that extra space between the axles to boost knee space.
The company claims the new IS offers 170mm of clearance to the front seatbacks compared with 136mm for the A4, 113mm for the 3 Series and 104mm for the C-Class.
And there is indeed vastly improved space in the back for knees, with only headroom a potential issue for tall passengers.
The leather rear bench of the Luxury model was beautifully supple and angled sufficiently to provide good under-thigh support.
There’s also a bonus for luggage capacity. Lexus’s GS and LS hybrid sedans have compromised boot space and no split-fold rear seat arrangement due to the positioning of the battery pack.
Lexus engineers, though, have managed to store the IS300h’s battery pack under the luggage deck board, creating a 450-litre volume.
There are gooseneck hinges and the boot isn’t that wide, but plenty of depth makes it usefully sized.
With only 30 litres less than the V6 petrol sedans, the IS300h’s practicality isn’t as compromised as other Lexus hybrids are to their conventionally engine siblings.
If low fuel consumption is a priority, the petrol-electric IS300h is a no-brainer over the IS250 and IS350 that can use up to double the petrol use based on official figures.
That will also help recover the $3000 premium over the equivalent IS250, though in Lexus World that’s already a relatively small gap between a petrol and hybrid model.
As for external rivals, you’ll naturally get more for your money with the Japanese luxury sedan than its competitors from Germany, including a warranty runs a year longer (four).
The Germans still have the higher badge cachet, though, and the Mercedes offers a more cosseting ride and the BMW delivers a more sporting drive.
And all three serve up a good choice of petrol and diesel engines, the latter being particularly effective for the kind of fluid motoring that should be a requisite of any luxury car.
Choosing the Lexus IS300h over a comparable A4, 3 Series or C-Class, then, is a far from straightforward decision.
But the hybrid at least moves the game forward for the 2013 Lexus IS more than the petrol V6s do.