The new Model Year 2011 Impreza WRX STI sedan has achieved Subaru’s fastest-ever lap time at Germany’s famed Nürburgring racetrack.

Four-time World Rally Champion Tommi Mäkinen recorded a time of seven minutes, 55 seconds – four seconds faster than Subaru’s previous best time, set in 2004.

Fuji Heavy Industries Ltd. (FHI), the manufacturer of Subaru cars, has released footage of Mäkinen’s drive on the Subaru Global website http://www.subaru-global.com/home.html or at Subaru Australia’s website, www.subaru.com.au

Subaru has been using the world’s toughest Nordschleife course at the Nürburgring since 1992, for advanced research and development, plus tests of the Impreza WRX and WRX STI models.

Major changes to the MY11 Impreza WRX STI include chassis and suspension set-up. Tests at the Nürburgring demonstrated the supreme overall dynamics and linear behaviour.

Tommi Mäkinen said: “The car was controllable with precise and faithful handling even on tricky corners. I could easily predict the car’s behaviour. That is exactly what Subaru is offering: confidence.”

Technical changes to the four-door Impreza WRX STI will also be carried over to the five-door hatchback model.

The revised Impreza WRX STI, including sedan variants, goes on sale in Australia in the last quarter of the year.

BACKGROUND

SUBARU AND NÜRBURGRING

Subaru has a history of advanced research and development at the Nürburgring.

It started in the late 1980s, evaluating suspension and tyres for the first generation Legacy.

In 1992 Subaru first tested the Impreza WRX there. Since then, Impreza WRX STI test vehicles have run the 20.8 km Nordschleife course at the Nürburgring. It is well known as the most difficult racetrack in the world, with more than 160 turns, and 300 metres difference in altitude.

The Nürburgring is regarded as the ultimate proving ground for auto manufacturers and Subaru has chosen it for many years in development of the WRX STI, to offer sheer excitement and unique driving feel.

The fastest driving at the track requires totally balanced superior vehicle performance, underpinned by Subaru’s consistent development philosophy: enjoyable, reliable, safe and secure driving with high performance, leading to driving confidence.
HISTORY OF DEVELOPMENT

The first test took place with the prototype Impreza WRX in 1992. Subaru engineers were stunned at the severe characteristics of the course. The front part of the vehicle was heavily stressed, especially on severe ups and downs. Subaru engineers realised the insufficient braking and suspension ability, and learned the importance of greater rigidity in the car’s front. The vehicle, nevertheless, achieved a lap time of 8’28’’93, thanks to its lightweight body and excellent stability, via Subaru’s Symmetrical All-Wheel Drive (AWD) system.

After the introduction of WRX STI in 1994, the prototype WRX STI version III was tested at the course in 1996, marking 8’10’’75, 18 seconds faster than the 1992 time. Engine output was increased with improved turbocharger and intercooler.

Transmission and brakes were also refined. Four-piston front and two-piston rear brake callipers were adopted, on the basis of past testing experience at the track. This eventually led to the adoption of Brembo brakes.

The second generation WRX STI, introduced in 2000, featured new items to further enhance driving performance: 225/45ZR17 tyres, six-speed manual transmission, new engine with variable valve timing control mechanisms and Brembo brakes. The car’s body rigidity also dramatically improved, enhancing collision safety performance. However, this resulted in a weight increase and the lap time did not meet Subaru’s expectations.

In 2002 WRX STI received a facelift with superior aerodynamics, a finely managed AWD system and new engine performance. The equal-length exhaust and Subaru’s first twin-scroll turbocharger increased the maximum output and torque. The newly-adopted auto mode in the driver’s control centre differential system optimised torque distribution between front and rear axles. Thanks to these advanced technologies, it recorded 8’06’’59.

WRX STI evolved again in 2004. Wheel hubs, rims and tyre width were enlarged. Helical-type was newly adopted in the front limited slip differential gear, to improve cornering stability. An undercover helped improve aerodynamics. The enlarged intercooler increased maximum torque. Mainly due to the enhancement of chassis performance, the test vehicle finally broke the eight-minute barrier at 7’59’’41.

Third generation WRX STI was unveiled in 2007. It adopted the totally new “Subaru Dynamic Chassis Control Concept.” Newly developed double wishbone rear suspension offered superior road-holding ability by optimising geometry, including toe and camber angles, and by regulating the lift motion. Subaru opted for the new five-door package, with a clear vision of what was most appropriate to be competitive in rallying, and what Subaru believed the ideal road sports car should be. Three key elements - traction, response and stability - were enhanced by the new chassis and package. However, rainy conditions made the tests incomplete, with no comparable lap times produced.

THE 2010 TEST

Development of the Model Year 2011 WRX STI focused on improved dynamics and precise handling, with every aspect tested under extreme operating conditions, including at the toughest Nürburgring racetrack. Subaru chose the new four-door sedan for 2010 testing. Some potential future model items were added to the test vehicle, with Subaru positioning the test as one stage in advanced research and development. Subaru evaluated the model’s performance, considering future product planning of the WRX STI.

The final test took place in April at the Nordschleife course. Subaru believes suspension performance is essential for high speed cornering with confidence. Therefore, the refinement of suspension and chassis were the main focus of the test, as well as the development of MY11 WRX STI. During testing, the car showed faster cornering speed. The test vehicle recorded 7’55’’00, the fastest lap time ever in a Subaru.

“The 2011 MY WRX STI test car balances excellent stability and handling performance at a high level, thanks to its refined suspensions”, explained Tommi Makinen. The legendary four-time World Rally Champion piloted the car. He has also been a long-time supporter of Subaru since driving for Subaru World Rally Team in 2002. “The car was really controllable with precise and faithful handling even on tricky corners. I could easily predict a next behaviour of the car, that is, I confirmed its evolved total driving control ability. Subaru’s renowned Symmetrical AWD system also greatly contributed to this performance. The outstanding achievement is not only a tribute to Subaru’s continued and earnest efforts, but also an evidence of confidence in driving a Subaru.”

MAJOR SPECIFICATIONS OF 2011MY WRX STI TEST VEHICLE:

Overall length x width x height: 4580 x 1795 x 1470 mm
Wheelbase: 2625 mm
Engine type: Horizontally-opposed four-cylinder DOHC 16-valve turbocharged engine
Displacement: 1994 cc
Transmission: six-speed manual
Tyres: 245/40 R18

MAJOR ADDED FEATURES TO THE TEST VEHICLE:

R205 model items (R205 is a special edition for Japan market).
Bigger turbocharger
Six-pot brake callipers
Flexible tower bar
Front lip spoiler

spec C model items (spec C is a special edition for Japan market).
Bridgestone Potenza RE070 tyres
Aluminum hood

Safety equipment
Full-bucket seat
Roll cage
Five-point safety belts

Advanced items
Under cover
Aluminium fenders