Subaru's new Impreza WRC contender
March 4, 2007 The Subaru World Rally Team (SWRT) has released details of the latest evolution of its rally challenger, the Impreza WRC2007, which will make its competitive debut in the fourth WRC round of 2007 next weekend at Rally Mexico in the hands of Petter Solberg and Chris Atkinson. Although outwardly similar to its predecessor, a number of key engineering improvements have justified the production of a new car for the remainder of this season. As the basis of a rally winning machine, few cars can match the competitive pedigree of the. First launched in 1992, the Impreza road car has developed in tandem with its rallying counterpart and over the last 13 seasons, has scored 46 WRC victories and lessons learned on the rally stages have been fed back into the production model. The targets were to produce a car with a more responsive front end with better traction and more balanced tyre wear, particularly on longer stages. To achieve that, SWRT applied a different philosophy into areas such as weight distribution, suspension geometry and differential set-ups.
“The car also has a different radiator and intercooler pack. We made an evolution in the middle of last season and, with the benefit of the new homologation, we’ve been able to make a further step on that. We have simplified the layout, which has improved the air flow, made the front end of the car easier to service and lost some weight,” said Steve Farrell, director of engineering for the Subaru World Rally Team.
“Externally, the differences are relatively subtle. The front bumper has been restyled to suit the new radiator pack and the bonnet vents are different – we have twin side exits on the bonnet this time rather than one central one.”
Richard Taylor, Subaru World Rally Team managing director adds: “Since the latter part of last year we’ve worked very closely with Subaru in Japan to look at certain specific areas of the 2006 car and bring the new version to fruition as quickly as possible. This season we have started to work with BFGoodrich and Mexico will be our first gravel event with its tyres, so we still have a considerable amount of learning to do in that respect.”
Like the road-going Impreza, at the heart of the rally car are two key parts of the Subaru philosophy, namely the Horizontally-opposed engine and the trademark Symmetrical AWD (All-Wheel-Drive). Through the work of STI and the Subaru World Rally Team, Subaru has established a two-way feedback process which complements both the road and rally car programmes.
Shigeo Sugaya, manufacturer principal, engineering, for the Subaru World Rally Team, says: “The collaboration between Subaru in Japan and England has worked extremely well to deliver the WRC2007 in a very short timeframe. Last autumn, engineers in Japan and England shared the idea before actual work started on both sides. Then development work was initiated as a joint project between the two teams.
“Our engineers in Japan are responsible for two main areas: the first is designing the bodyshell, including aerodynamics, and the other is improving the power unit. The engine itself contributes to further improving drivability in the middle to low speed range, which worked effectively in the Impreza WRC2006. As with previous designs, the engine is an all-aluminium construction, but the further use of light-weight materials means it is even lighter than before.
“On top of that, we work very closely with the Subaru World Rally Team engineers on specific projects and offer general support as and when it is needed. We also set up smaller groups including engineers from both Japan and England to develop areas such as the suspension or aerodynamics. The groups communicate directly, while my role is to oversee the success of each project. The WRC2007 does not represent a radical change for the team, instead we have made small evolutions in several areas.”
The team has used the WRC2006 for the first three rallies of the 2007 season and has scored points on each outing. In parallel, the new car has been undergoing testing on gravel roads in Italy and Spain. The two Subaru World Rally Team crews will drive the Impreza WRC2007 for Mexico and the subsequent 12 rounds of the WRC.
The two Subaru Impreza WRC2007s set off today from the Subaru World Rally Team’s headquarters in Banbury, England to embark on the 5000-mile trip to Mexico in preparation for their debut in the World Rally Championship.