Thursday | 16 Oct 2014

How to: 75-minute asphalt makeover

With an opening day on gravel and the next two on asphalt, cars at RallyRACC Rally de España (23-26 October) will have to be rebuilt on Friday night. And to keep the pressure on, teams have just 75 minutes to get the job done.

M-Sport engineer Tim Jackson will be supervising the transformation of Ken Block’s Fiesta RS in Spain. He told how his team would squeeze the work in:

0-15 minutes
“The car will have driven six stages on Friday, so when it comes in we’ll do the usual checks, look at the data and note any issues the driver has reported. Minor damage isn’t a problem because we will replace most of the parts anyway. We take off the gravel components as quickly as possible, including front and rear crossmembers, steering rack, gearbox, rear diff and all suspension and brakes. We can have eight people working at once because we are allowed to stagger service times. After 15 minutes everything is off and the car looks quite bare.”

15-30 minutes
“Now we are ready to fit the asphalt parts. The most important thing here is preparation; it’s essential to get a head start. All the components are already laid out, mostly as sub-assemblies that have been put together in our workshop in the UK. The rear crossmember is the brace for the suspension and is pre-fitted with the asphalt-spec diff, suspension links, uprights and even the dampers. We fit the whole unit in one piece and secure it with eight bolts. The front is similar but includes a steering rack and steering arms pre-adjusted to give the correct asphalt geometry.”

30-40 minutes
“Most of the rear of the car will be back on by now - certainly the crossmember and rear diff. While that’s going on, the guys at the front are doing engine checks and other routine servicing.”

40-50 minutes
“The gearbox is in now, and that contains the front diff. These and the rear diff are a different specification to the gravel units because of the car's speed, grip and wheelspin characteristics on asphalt roads.”

50-60 minutes
“The suspension and brakes will be fitted. The brake discs are bigger, up from 300mm to 355mm diameter all round, and fitted with water-cooled calipers. The whole system needs to be bled. Asphalt dampers are bolted on and it’s starting to look like a car again.”

60 minutes 
“All the major work should be done. Now we work around the car to check geometry, ride height and camber settings. These are different because the car runs about 60mm lower in asphalt specification. Usually it’s just a case of fine-tuning, because we have already adjusted the components in a controlled environment at M-Sport. Then we weigh the car to check we are not under weight. In general, gravel components are stronger and heavier than the asphalt versions, and that goes for wheels and tyres too. We’ll add ballast if necessary.”

65 minutes
“If everything goes to plan the car should be on its wheels and ready to go at 65 minutes. That gives us 10 minutes of contingency time just in case...”

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