For 1993, Prodrive determined that a smaller, more nimble car would be a better foundation for a rally car, initiating development of a Group A Impreza rally car. The Impreza was 160 mm shorter overall and featured a 60 mm shorter wheelbase compared to its predecessor, with a more neutral front/rear weight distribution. It was also the first rally car to incorporate active differentials. The initial Impreza rally car debuted at the 1993 Rally Finland, driven by Vatanen and Alén, with Vatanen achieving a second-place finish on its debut. In 1994, the Subaru team transitioned from Michelin to Pirelli tires. Responding to 1995 FIA mandates for more restrictive air intakes intended to reduce car speed, Subaru introduced a new boxer engine with revised camshafts and a different compression ratio.
The 1997 season saw the introduction of the World Rally Car formula by the FIA, allowing teams greater design freedom in areas such as vehicle width, suspension geometry, aerodynamics, intercooler capacity, and engine modifications. This led to a completely redesigned Impreza, the WRC97, featuring modified camshafts, cylinder ports, and combustion chambers. The new body style adopted a two-door configuration, and the car’s width increased to 1,770 mm (69.9 in) with revised suspension geometry. Power output rose to 224 kW (300 hp) @ 5500 rpm, with torque reaching 470 N⋅m (347 lb⋅ft). The WRC99 featured an electronically controlled, hydraulically actuated semi-automatic transmission with steering wheel-mounted paddles, similar to those used in Formula 1 cars, enabling faster gear changes and reducing wear on the dog gears. Subaru was the first rally team to implement this technology, which remained in use until it was prohibited by the 2011 championship rules.
The WRC2006 received the production car's second facelift with the "hawk eye" headlamps. Rule changes in that year banned active differentials and water injection, and mandated the re-use of cars and engines on selected events. The WRC2007 featured new dampers, a different radiator and intercooler arrangement, as well as improved weight distribution, suspension geometry and differential set-ups. Each transmission in the WRC2007 takes 85 hours to build and costs over £75,000. The front and rear differentials take around 16 hours to build and cost about £20,000 each. The car's engine, transmission and differential are individually oil sealed, allowing for quick replacement in 10–12 minutes. The transmission utilizes a hydraulically actuated and electronically controlled semi-automatic gearshift operating at a pressure of 17 MPa (2,500 psi), enabling gear shifts in under 0.1 seconds.
The WRC98 was an evolution of the WRC97, incorporating computer-controlled active differentials in the front, rear, and center, along with an electronic throttle. However, mechanical failures plagued the team, hindering their championship aspirations. The WRC2000 debuted at Rally Portugal and secured a victory, benefiting from lessons learned from the WRC99. The WRC2001 introduced a new look based on the GD chassis Impreza WRX, featuring four doors, revised aerodynamics, improved weight distribution, and a lower center of gravity, while retaining the mechanical developments from the previous year with subtle refinements. The WRC2002 saw continued development, with improvements to the driveshaft, transmission housing, steering column, turbo-charger, and manifold, as well as weight reduction of 15 kg (33 lb).
The WRC2003, introduced at Rallye Monte Carlo, featured a revised appearance based on the updated Impreza production car, with "bugeye" headlamps replaced by "blobeye" lamps. Technical improvements focused on the turbocharger and engine to increase low-RPM torque and improve driveability, alongside a lighter and stiffer body shell. The WRC2004 saw refinements to the engine and body panels, with a revised gearbox introduced mid-season. The WRC2005, developed jointly by Subaru and Prodrive, featured a stiffer, wider bodyshell (30 mm wider) with more composite body panels to reduce weight. Engine enhancements included a lightened flywheel and a revised IHI turbocharger, along with revised water and fuel injection systems.
The WRC2007 was considered underachieving compared to the competition, suffering from handling problems that led to Subaru’s withdrawal from Rally Finland. In December 2007, Subaru began testing the WRC2008, based on the new GR chassis Impreza WRX, featuring a double wishbone rear suspension, which was later reverted to a MacPherson strut design. The WRC2008 debuted at the Acropolis Rally of Greece, achieving a second-place finish with Petter Solberg. Chris Atkinson’s third-place finish at Rally Finland was the final WRC podium for the car and the Subaru World Rally Team, which withdrew from the championship at the end of 2008 due to the financial crisis.
In 1995, the FIA mandated more restrictive air intakes in an effort to slow the cars down. In 2006, rule changes banned active differentials and water injection, and mandated that teams must re-use cars and engines on selected ‘pairs’ of events. The semi-automatic transmission technology pioneered by Subaru was ultimately forbidden by the 2011 championship rules.
The semi-automatic transmission initially implemented on the WRC99 was adopted by all WRC cars until its prohibition in 2011. The WRC2008 benefited from a decreased polar moment of inertia due to smaller overhangs and featured a double wishbone rear suspension, although this configuration was later deemed suboptimal and reverted to a MacPherson strut design.
Gallery · 4 related images
