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First drive: Subaru Impreza leads with idle-stop

Around the corner: First examples of Subaru's next Impreza will appear on our shores in January 2012.

Idle-stop for all 2012 Imprezas as Subaru attacks fuel economy with all-new model

24 Oct 2011


SUBARU’S all-new Impreza will get idle-stop across all models when it lands in Australian showrooms in the first quarter of 2012, making the fourth-generation Impreza the first mainstream small car range to get the fuel-saving technology from top to bottom.

The closely related Subaru XV compact SUV will also get the system on all variants, making it the first small SUV of any type in its class to embrace idle-stop when the new model goes on sale in January.

The system contributes to a fuel economy improvement of more than 20 per cent for both models, with other savings coming courtesy of a new and more efficient 2.0-litre “boxer” flat-four engine, fresh transmissions, electric power-assisted steering and better aerodynamics.

Even bigger gains are in the pipeline, with an all-new diesel engine expected to appear in the XV line-up – and possibly Impreza – within 18 months.

Fans of the turbocharged WRX and STi high-performance models need not rush to their dealerships any time soon, as fresh iterations of these hot models are at least two years away, maybe even three.

For now, the Impreza and XV crossover – which has been split from the Impreza range as a standalone model for the first time (see separate story) – are powered by a single normally aspirated 110kW 2.0-litre version of Subaru’s new boxer engine that made its debut in 2.5-litre guise in Forester earlier this year.

While Subaru Australia has high hopes for the new Impreza, it will be on restricted supply for a year or so, as the Japanese company fights back from the devastating earthquake in Japan in March.

Subaru Australia managing director Nick Senior said he hoped to maintain the Impreza’s current 800-a-month sales rate through 2012.

“We are not expecting a huge increase in volume any time soon, though,” he said in Japan, where Subaru gave Australian journalists a drive of both the Impreza and XV at its proving ground at the weekend.

2 center imageThe Impreza originally had been expected to go on sale in August this year, but the launch blew out drastically due to the quake, and at one point was expected to be delayed by up to a year.

However, Subaru parent company Fuji Heavy Industries has put in the long strides towards recovery, and the first Impreza demonstrators will arrive in Australian showrooms in January, with customer stocks following about the end of February.

So far this year, Subaru has sold 8899 Imprezas – down 0.8 per cent on the first nine months of 2010 – but September sales plummeted almost 45 per cent as stocks of the current model started to run short.

As before, the new Impreza will be offered in two body styles – a sedan and five-door hatchback, both with Subaru’s trademark symmetrical all-wheel drive.

Although the overall exterior dimensions are similar to the current model at 4580mm long for the sedan (hatch 4415mm) and 1740mm wide, the wheelbase has been stretched by 25mm, to 2645mm, helping to deliver more interior space.

Rear seat passengers get an extra 25mm of knee room, while foot room has been improved by more than 40mm, thanks to higher front seats.

Skinnier doors also provide more shoulder room, helping to address one of the main customer complaints about the third-generation model – lack of spaciousness, especially in the rear.

Subaru has employed more high-strength steel to both improve body strength and reduce weight, although the 20kg saving has been soaked up by the addition of extra fuel-efficiency systems such as idle-stop.

The A-pillars and windscreen are more steeply raked than before, with the base stretched out towards the nose by an extra 200mm to deliver improved all-round visibility for the driver, along with better aerodynamics.

The change also gives the Impreza a roomier feel, enhanced further by a lower and less voluminous dashboard.

The most noticeable improvement to the Impreza interior is the application of new, more up-market soft-touch finishes, lifting the ambience by several notches over its hard-plastic predecessor.

The various dials and meters are ringed by elegant chrome, while the tacho and speedo have simple and effective white-on-black numbering.

Cubbyholes for all manner of items are thoughtfully scattered around the cabin, not only including slots for mobile phones and similar modern paraphernalia but even pen holders inside the centre console.

Luggage space is increased and seat-mounted child restraint attachments mean the cargo area of the hatch is unencumbered by belts.

Under the bonnet, the Impreza is all-new, although most of the changes have been wrought to improve fuel economy, not acceleration.

The latest Euro 5 FB engine has the same power (110kW at 6200rpm) and torque (196Nm at a high 4200rpm), but fuel economy has been slashed by up to 22 per cent.

Lighter engine parts such as conrods and pistons, a move to roller rockers and a more efficient oil pump were among the changes to improve fuel economy.

With a longer stroke and variable valve timing applied to the exhaust valves as well as the inlet side, the engine has more pulling power lower in the rev range than the previous engine.

Mated with a choice of new six-speed manual gearbox or all-new continuously variable transmission (CVT) – called Lineartronic by Subaru – the engine cuts the Impreza’s zero-to-100km/h sprint time from a lackadaisical 11.5 seconds to a better – but not blistering – 10.7 seconds.

The slurring CVT makes it feel slower, but the reward is at the petrol pump.

The CVT is smaller and lighter than the similar unit employed in the Subaru Liberty and Outback, but is heavier than the old four-speed transmission of the previous Impreza.

A six-step “manual mode” can be operated by paddles on the steering wheel, although the effect is the transmission equivalent of dancing with your sister – not that exciting.

A taller final drive on both manual and CVT models makes for a relaxed driving experience at highway speeds and, while the whole car seems more refined and solid, the few laps we did of the sterile Subaru high-speed test circuit and handling course under strict conditions was hardly a definitive test.

The new CVT is said to contribute to about a quarter of the 20 per cent improvement in fuel consumption, with the honours shared by the new engine, the idle-stop system, slippery aerodynamics and – to a lesser extent – the electric power-assisted steering.

According to Subaru’s own figures, the manual Impreza returns a combined fuel consumption test reading of 7.1 litres per 100km, down from 8.9L/100km.

The thrifty CVT version comes in for an even bigger improvement, down from 8.8L/100km for the old four-speed auto to 6.8L/100km, while CO2 emissions have been chopped 24 per cent, to 157 grams per kilometre for the CVT-equipped models and 164g/km for the manual.

The idle-stop system is fitted to both manual and CVT-equipped cars. On the CVT, the driver just needs to come to a full stop with a foot resting on the brake, and the engine will cut in about 0.3 seconds. Lifting the foot from the brake fires it up again.

On the manual, the gearshift has to be moved into neutral and the foot taken from the clutch pedal to trigger the idle-stop. Depressing the clutch, selecting first gear and lifting the foot from the brake reverses the process.

The latter seems quite laborious, but is effective in practice.

Flying in the face of the drive for improved fuel economy are larger wing mirrors that improve rear visibility but contribute to wind noise at 100km/h or more.

This probably seems more noticeable because of the efforts made to suppress road noise – including a 25 per cent stiffer body – which seem effective, although a test on Australia’s course-chip bitumen will tell more.

Subaru has stuck with MacPherson strut suspension on the front and double-wishbone on the rear, but with various changes to make the car corner flatter – an attribute that is assisted by the Impreza’s low centre of gravity due to the boxer engine layout.

While the road surfaces at the proving ground in central Japan were mostly smooth, one big bump strategically placed mid-corner on the handling course gave an insight into the effectiveness of the Impreza’s bump absorption – truly composed.

Subaru claims the floor vibration has been improved markedly, and is now superior to that of the Volkswagen Golf and new Mazda3.

The Impreza will be offered in three variants at launch – 2.0i, 2.0i-L and 2.0-S – in both hatch and sedan.

Although the full specifications and pricing will not be announced until closer to launch, the base model will get steel wheels, cruise control, seven airbags and auto air-conditioning, with free metallic or pearl paint.

The 2.0-L adds electric sunroof, multi-function display with rear-view camera, dual-zone climate control, 16-inch alloy wheels, steering wheel audio controls, rear privacy glass and front fog lights.

The optional sat-nav also has SMS voice-to-text and voice command.

The flagship 2.0i-S adds leather trim, eight-way electric driver’s seat, alloy pedals, HID Xenon headlights with washers.

Eight different functions can be selected on the multi-function screen – which is standard on the top two models – including eco-gauges to chide the driver into even more heroic fuel savings. These include a meter to show how much fuel has been saved by idle-stop on your journey.

The top two variants have three LCD screens – one for the multi-function screen atop the dash (under an effective verandah to block sunlight and reflection on the windscreen at night), a bigger screen in the middle of the dash for the rear view camera and sat-nav where fitted, and a smaller screen between the speedo and tacho for instant fuel readout and other information.

Bluetooth audio and phone streaming, as well as other forms of connectivity, are supported, with the various modes selected via a steering wheel switch.

A centre armrest is standard on all models, but slides forward on the top two.

Seats are comforting, not cosseting, while Subaru engineers have managed to improve access and egress for the car’s occupants, even dropping the sill height by 35mm.

The big unknown about the new Impreza and its XV stablemate is pricing, which will speak volumes about the value of the changes brought to bear on the new generation.

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