Subaru Impreza plays catch up

SUBARU has revealed that improved fuel consumption was the main focus in the development of the fourth-generation Impreza small car.

But snapping hot on the heels of that is significantly more rear seat space, along with improved interior quality and better driveability, according to G4 Impreza project general manager Akihide Takeuchi.

“Market issues means that Subaru had to change the Impreza quickly … in a new green-minded era,” he told GoAuto at an event associated with the New York International Auto Show last week.

“We needed to increase the Impreza’s environmental credentials ... by making the Impreza more efficient.”

Due in Australia late in the fourth quarter of this year in five-door hatch and four-door sedan guises, the boxer engined, all-wheel-drive small car range is approximately 80 per cent changed from its predecessor at cost level.

Surprisingly, the four-door sedan was styled first, with the five-door hatch evolving from there. Designed in Japan, Subaru says it tried to achieve a ‘California view’ with the latest Impreza.

The series will now be split into mainstream (Impreza), performance (WRX/STi) and compact SUV/crossover (XV) guises, with each boasting a unique appearance to underline their differing duties. At the time of writing, Subaru had not yet confirmed XV production.

The G4 Impreza follows in the footsteps of its Mk5 Liberty/Legacy/Outback big brothers in gaining a completely redesigned ‘automatic’ transmission as one of its big-ticket attractions.

A lighter and more compact evolution of the Lineartronic continuously variable transmission (CVT) that debuted in the 2009 Liberty range, it heralds significantly improved fuel economy combined with lower emissions. A six-speed manual gearbox will also be standard for Australia.

Meanwhile, a completely redesigned naturally aspirated 2.0-litre boxer engine also finds its way in the MY12 Impreza range.

A longer-stroke FB-series unit closely related to the 2.5-litre unit first featured in the MY11 Forester earlier this year, it includes double overhead camshafts and Dual Active Valve Control System on both the intake and exhaust valves for measurably improved fuel efficiency without performance sacrifice.

The new drivetrain required a redesign of the front-end structure and firewall, with added strength built in to help safety and quell noise and vibration issues.

However, in the interest of keeping weight down, the current Liberty’s much-touted engine cradle system is not employed here.

Switching to an electric power steering system also keeps the kilos down, as well as enhances packaging and fuel economy.

No diesel engine details have been revealed for now, but an improved version of the 2.0-litre boxer diesel available in Europe (as well as the Forester and Outback) is set to debut in the Impreza for Australia.

A CVT eventually will join the six-speed manual that has been the sole transmission choice with the existing diesel offerings when Subaru is satisfied the gearbox will be able to cope with the 350Nm-plus torque load.

Improving driving enjoyment was another priority for the G4 Impreza engineering team.

“Although improving fuel economy is the main goal, being ‘fun to drive’ while providing ‘driving pleasure and excitement’ is just as important,” Mr Takeuchi said.

The long-serving Subaru engineer revealed that the Volkswagen Golf/Jetta and Mazda3 were the main dynamic benchmarks, along with the Honda Civic and to a lesser extent the Toyota Corolla.

Achieving the desired packaging within a similar footprint to the outgoing model without adding weight proved to be one of the biggest challengers on the Impreza project.

In the end, increasing the G4’s wheelbase by 25mm helped increase rear legroom by a much-needed 49mm, to make the Subaru much more class-competitive. Pushing the A-pillars forward by 200mm also helped increase cabin space significantly.

Other modifications over the old model include a slightly higher seating ‘hip point’ to allow for easier entry and egress (as well as a better view out) the doors now open wider for better access and the boot is now bigger than before – it can now hold four golf bags instead of three.

“We wanted to improve the quality, roominess and ‘brightness’ of the Impreza’s interior,” Mr Takeuchi said. “We needed to make it more inviting and classy.”