Subiesport Magazine

Sideways at Prodrive UK

Just before Christmas I was running a series from my trip to Rally GB in 2007. I've dusted the files off and have one more from that series to share. This was the visit to the Prodrive test track in Warwickshire.

I had a chance to drive a Subaru Type UK 2007 STI and a Group-N WRC car on the high-speed course (my first time in a right-hand drive), plus I had a little fun on the ice simulator. Prodrive has one of only two such simulators in the UK.

Thanks to Subaru of America for hookup us up. Enjoy the video, just after the jump.

WRC Brakes: Asphalt vs. Gravel

Brakes are an essential component of any WRC car, and in slowing the car down play just as important a role in boosting overall speed. Quite apart from simply slowing the car, drivers use the brakes to position and balance the car on its approach to corners and to slide through tight hairpins while maintaining engine speed.

Each car’s brake setup is also different for gravel and asphalt rallies, owing to the different demands and usage in each condition.

For an asphalt rally, the Impreza WRC2007s use 366mm AP Racing brake discs at the front of the car and 305mm discs at the rear. These are wrapped by eight-pot AP calipers up front and four-pot variants at the rear. On asphalt there is generally more available grip than on gravel, so more force can be exerted through the brakes without the wheels locking, generating more friction. Speeds are also generally higher, leading to higher loads.

Subaru WRC drivetrain: by the numbers

Where far more than expected meets the eye, we look at the complexities of the gearboxes and differentials used in the Impreza WRC2007, and what goes into making them work:

The Subaru World Rally Team has produced over 100 WRC gearboxes since 1999. Almost 50 WRC differentials have been built since 2004. Each gearbox takes 85 hours to build and costs £75,000. Coupled with the rear differential the transmission system contains over 700 individual components.

Each differential takes 16 hours to build, and costs £20,000. The front and rear differentials share components to reduce costs, whereas the centre differential is unique. Once a gearbox has been built, it takes three hours for the team’s dedicated dyno to run through the complete test procedure before it is used on a rally.

WRC-level fitness training for SWRT

The sport of rallying, especially at the competitive sharp end of the World Championship, is incredibly tough and demanding of both cars and drivers. Teams of engineers channel huge focus and resource into the development of the vehicle side of the equation, but what of the human element?

It’s well known in motorsport that, while engineers are working to find tenths of a second, a driver who tires halfway through a stage suffers reduced focus and slower reactions, leading to the potential loss of seconds, not just tenths.

The job of ensuring the drivers are their absolute peak falls to John Mills, the Subaru World Rally Team’s performance trainer. This doesn’t simply mean that John sets them a training routine and stands back, as he explains: