Aboard the 1999 Impreza, Burns and Reid took three wins and three podiums in their first full season with SWRT

In the late 1990s and into the turn of the millennium, the technology being used in rally cars was running rife and the Impreza employed the very latest gadgetry to take Richard Burns to the 2001 WRC title.

1999 – Subaru Impreza WRC99
The WRC99 didn’t necessitate a new homologation but under the skin was very different to its predecessor. With the age of technology rife, this was a very cutting-edge car and most of the development work reflected this, focussing on the interaction and endlessly adjustable parameters of the automatically controlled systems in use.

The semi-automatic H-pattern gearbox came into its own this year. While it had been used in one form or other since 1994, this was the first year in which the standard manual gear lever was removed from the car. Instead, the driver changed car by pushing or pulling a paddle behind the steering wheel, and a complex series or hydraulic actuators and electronics changed gear.

This system changed gear faster and with better precision, not only reducing time off the throttle between gear changes but aided the lifespan of the gear ratios with smoother changes.

The Impreza WRC99 also incorporated a fly-by-wire throttle for the first time, pioneered by Subaru and Prodrive. This meant that there was no throttle cable or linkage to the pedal, but that it was all electronically controlled. Demonstrating the complexities of interrelated systems, this was tied to the gearshift systems to allow the driver to change gear without lifting his foot from the pedal. The electronics ensured engine revs were cut accordingly and then matched with wheel speed once the next gear had been selected.

The car also benefited from a new turbocharger, and a lighter and stiffer rollcage to reduce the centre of gravity. On the notoriously tough-on-brakes Rally Catalunya, six-pot water-cooled brake calipers were used.

2000 – Subaru Impreza WRC2000
Subaru started the 2000 season using the Impreza WRC99 for the first three rounds. On its final swansong on the Safari rally it claimed victory, before being replaced for Portugal by the all-new Impreza WRC2000.

The last of the classic shape Imprezas, it drew upon the knowledge amassed by Subaru and Prodrive since the early days of the Legacy and was a complete redesign, as opposed the incremental developments that had gone before it.

Every component on the rally car was examined for possible improvement and although the end product looked similar in external appearance to the WRC99, underneath that familiar skin around 80 percent of the car was new.

Led by designer Christian Loriaux, fundamental changes were implemented to increase stiffness. The rollcage was joined directly to the suspension points for maximum strength, and it was the first time that a team had used the rear differential as an integral part of the rear suspension.

Changes in the engine bay were also fundamental: the huge vents in the bonnet were used to vent the hot air immediately away from the radiator, hence shielding the rest of the engine bay from excess heat. The air intake was also insulated and made more direct to improve air flow. Centre of gravity again ruled supreme: the pedal box was the only item of its kind in the WRC to be floor mounted, to keep the pedal pivots closer to the floor, and even the turbocharger was lowered by 10mm for this end.

2001 – Subaru Impreza WRC2001
In contrast to the incremental body-styling changes of recent years, the WRC2001 represented a significant visual change for Subaru, not least the return to a four door platform that resulted from the parallel development of the road and rally variants.

The proven rally-winning mechanical development that had gone into the WRC2000 was transferred to the new variant, and even more emphasis was placed on aerodynamics, bodyshell strength and weight distribution. Peter Stevens, the guru behind the WRC97, was again responsible for the external elements of the car.

The four-door bodyshell, which shared an intentional striking similarity to the STi roadcar launched that year, was an impressive 250 per cent stiffer than its predecessor, made so by marked improvements in materials technology. The four-door car also allowed greater flexibility with the location of the fuel cell and of various ancillary components to further improve performance.

With the radical new styling, Stevens’ brief was to ensure maximised airflow to the engine bay and intake manifold. The team experimented with air intakes throughout the year, sometimes opting for the bonnet-mounted air scoop and at other times taking air from behind the headlamps at the front of the car.

As the technology behind them improved their effectiveness, the brake discs front and rear were made smaller to reduce the un-sprung weight at each corner of the car. Under new regulations introduced for the start of the year, forged wheels were banned forcing teams to opt for heavier cast items.

The cockpit controls also started to move towards the centre of the car and into a console between the front seats.