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Rally Japan, Subaru's home event, is always a notable occasion for every Subaru World Rally Team member, but the 2006 rally was particularly special for the team's transmission department as they watched the 100th Subaru World Rally Team gearbox ever produced in action. The 100th gearbox was fitted to Toshi Arai's Subaru Impreza WRC2006, which finished sixth overall.

The first Subaru World Rally Team gearbox made its competitive debut in the 1999 FIA World Rally Championship season opener, the Monte Carlo Rally, in Juha Kankkunen's Subaru Impreza WRC1999. The Flying Finn finished second overall.

Between that first rally and 2004 there were only minor changes to the gearbox design as the team sought to improve the reliability, speed and accuracy of the gear changes. Five years later, in the middle of the 2004 season, a revised design was introduced with new differentials, software and gear ratios to improve acceleration and top speed.

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The current six-speed semi-automatic gearbox is built in-house at the Subaru World Rally Team headquarters in Banbury. Each gearbox comprises over 350 components and takes approximately one week to build from start to finish. This year the design was enhanced to improve the speed of the gear change; Petter Solberg and Chris Atkinson can change up a gear in 0.018 milliseconds, as fast as a Formula 1 car.

Paul Roberts, Subaru World Rally Team transmissions supervisor, said, "The gearbox design has evolved since the first 'box made its debut in Monte Carlo in 1999. As a team we've worked to increase efficiency and are proud that our gearbox is one of the most technically advanced in the rallying world. It takes a lot of hard work to produce each 'box, and each person works on a gearbox from start to finish so they think of it as their own project. I can't quite believe that we've now made 100 of them!"

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You would expect to find it on a luxury road car, but it will probably come as a surprise to learn that the Subaru Impreza WRC2006 is also fitted with cruise control, a system that enables a driver to set and automatically maintain a given speed. Thought rally drivers wanted to go as fast as possible? Of course - this advanced system is only used on the road sections of rallies, where it allows Petter Solberg and Chris Atkinson to keep their cars at a steady, constant pace for long distances.

Cruise control was introduced by the Subaru World Rally Team in 2004 to try and improve fuel consumption on rallies with long distances between stages. It's particularly useful in Rally Japan, the event with the longest liaison sections in the whole championship. Over the course of this year's three-day rally, crews covered 1240km as they drove between stages and service - that's the equivalent of driving from the team's headquarters in Banbury, in the heart of Great Britain, to Berlin, in the east of Germany.

Keeping the car at a steady pace over that kind of distance also requires extreme concentration and focus from drivers, especially in Japan, where the speed limits are very low; just 40km/h in built-up areas and 60km/h elsewhere.

Nick Dennish, Principal Engine Engineer, explained to swrt.com how the system worked. "When the drivers come out of the stage onto the road they can enable cruise control by pressing the 'LC', or launch control, button on the bottom of the steering wheel. At this point the driver does not need to use the throttle at all - once the system is engaged, the speed of the car is adjusted by pulling the gear-shift paddle to go faster, or pushing it forwards to go slower. Once the driver is happy with the speed, the car will hold it without any input from the driver or passenger."

Dennish continues that the system can be easily deactivated. "The system is cancelled by either pressing the clutch or footbrake, or activating the handbrake. Cruise control has to be cancelled before the driver can use the paddle to change gear. Petter and Chris will do this just before they get to the time control at the beginning of the stage, ready to start the next test."