Taking the rough with the smooth
If you are unfamiliar with the FIA World Rallycross Championship then allow me to enlighten you. Imagine merging the brutal environment of a rally with the chaos of a touring car race, add a jump in, and some drifting, and you are getting close. The 600bhp turbocharged Supercars punch 0-60mph (100km/h) acceleration times faster than F1, so the dash to the first corner becomes a six-way drag race. This is followed by six laps of hardcore racing on tracks where up to 67 per cent of the lap surface is dirt, while the other 33 per cent is asphalt. Then there is the joker lap, which is an alternative section of track that adds at least two seconds of lap time which every driver needs to complete once per race. In short, WRX races are close to controlled carnage.
Yet while rallycross is great entertainment, it also presents a rare and fascinating engineering challenge. Just how do you go about designing and setting up a car to maximise performance when it has to both drift on dirt like a rally car and accelerate on tarmac like a GT racer? ‘The difficulty is you have tarmac with very good grip and then you have gravel sections of the track with much less grip. Getting a good car to deal with both is tricky,’ explains Kenneth Hansen, team principal at Team Hansen and a 14-time FIA European Rallycross champion.
Surface tension
Graham Rodemark, engineer and crew chief at Team Hansen, adds: ‘In many of the circuits, especially the newer ones, you have the F1 aspect of very smooth and fast tarmac corners where you don’t need that much travel within the suspension system and you want really hard springs to support the car. Then when you are racing on the dirt surface you want to start using a WRC gravel rally kind of idea. Trying to combine that with a formula car-style suspension for tarmac is tricky, so in rallycross it is all about achieving a happy medium.’
