From Subaru Press [ 28/02/2005 ].
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After a 12-month joint development programme involving teams at Fuji Heavy Industries (FHI) in Japan and the Subaru World Rally Team (SWRT) in England, the latest evolution of the Subaru Impreza World Rally Car, the Impreza WRC2005, will make its competitive debut on 11 March at Rally Mexico.
The eagerly anticipated new model replaces the Impreza WRC2004, the car that propelled Petter Solberg to five WRC victories in the 2004 season and to another win on its final event, Rally Sweden, a fortnight ago.
With six World Rally Championship titles and 44 outright rally wins in the past 12 seasons, the Impreza has been the defining car in Subaru's elevation from road car manufacturer to legend in world rallying. From its inception in 1993, the Impreza has provided a sensory assault on motorsport fans across the globe, and the latest model, the result of more than ten years of rallying experience, will ensure the car remains at the top of the WRC throughout the current season.
Featuring a wider track, revised styling, composite body panels and a host of engine and suspension enhancements, the Impreza WRC2005 is the ultimate development of a rally car and represents a landmark in the collaboration between engineering and design teams in the UK and Japan.
Not only have the teams worked more closely than ever before but, for the first time, the Impreza WRC2005 has been styled by the design team at FHI led by chief designer of Advanced design, Andreas Zapatinas. "In terms of airflow, the team in the UK worked on a design concept, but the wind tunnel testing, evolution of the aerodynamic package and final styling was carried out by the design team at FHI," said SWRT principal David Lapworth.
"FHI designing the World Rally Car is perhaps the most visible example of the working relationship between Japan and the UK, which is bringing the road and rally car closer together all the time. As the collaboration goes from strength to strength it enables us to get involved earlier in the process of designing the road cars and gives the engineers and the stylists that are involved in the road cars, a better insight into the requirements of the rally programme."
Built to take full advantage of the FIA's revised world rally car dimensions, the Impreza WRC2005 bodyshell is wider than its predecessor by 30mm, which gives it a slightly more aggressive look in the front and rear wheel arches. Another fresh feature of the exterior styling is the carefully sculpted wheel arches, penned by the Japanese stylists, which help balance the increased track with the design of the front and rear bodywork.
"The wider track makes a significant improvement to the handling of the car, especially on tarmac," said Lapworth. "It's all about weight transfer. The track width and the centre of gravity are inter-related. In this case, making the car wider has the same effect as making it lower, which is very beneficial."
As well as being stiffer than the WRC2004, the bodyshell of the Impreza WRC2005 features more composite panels than any of its predecessors. These include new front and rear wheel arches, in addition to the front and rear bumpers.
At the front end, the layout of the radiator and turbo intercooler follows the same basic concept as before, but has been further refined. The re-styled front bumper incorporates lessons learned over the last 12 months and efficiently manages the flow of air around the front of the car and through the cooling systems.
To ensure the new car goes as well as it looks, the engine and suspension systems have been modified. Subaru's 1994cc horizontally opposed 'boxer' engine receives a wide range of performance enhancing upgrades, including a new IHI turbo-charger, new water and fuel injection systems, a lighter flywheel and a host of other lightweight components.
"The engine project is another good example of our joint collaboration," said Lapworth. "Work was split between the teams in the UK and Japan, and the result is a positive step forward. Our research and development team in the UK put a huge amount of effort into the turbo project and, in conjunction with FHI and STI, worked to develop an engine that delivers more power, torque and response. The new water injection system is able to deliver precisely the right amount of water to each of the four cylinders and is a significant improvement over the previous unit."
The Subaru six-speed electro-hydraulic gearbox, first introduced in 1999, benefits from the addition of latest-specification hydraulic components. Inside the cockpit the on-board electronics systems have been re-packaged into a number of separate modules, allowing for easier servicing during rallies.
Components in the car's suspension system have been improved and the geometry has changed to take into account the new width. To reduce flex in individual parts, the latest computer design techniques were used to improve the weight/stiffness ratio of each component, while changes to the suspension strut mountings allow for quicker camber adjustments.
Final development testing of the Impreza WRC2005 took place in Sardinia earlier this month, with driver feedback from Pasi Hagstrom, Chris Atkinson and Petter Solberg. "Behind the wheel you quickly get the feeling that it's a much better overall package than the previous model," said Solberg. "There are lots of small improvements, but I was especially impressed with the chassis development work. The car feels much better balanced and has more traction, factors which should be especially noticeable in Mexico. The engineers have made more progress with the engine too, which has better torque and throttle response. Without doubt, this car has more to deliver over the coming year, but I'm very happy with what we already have and am looking forward to taking it out in Mexico."
"We're keenly anticipating the car's debut in Mexico," said Lapworth. "The future will be bright for the Impreza WRC2005, but what's more exciting for the longer term development of the Impreza is the way our colleagues in Japan are now able to take SWRT's requirements into account even earlier in the design process. Our collaborations are mutually beneficial and all the ideas derived from the WRC activities are fed back into the road car development programme, which in turn provides the rally team with a higher level of base car on which to work. Looking to the future development of Subaru cars, with our input from the initial sketches, the mutual co-operation becomes very exciting."