RALLY: Interview with M-Sport Project Mananger Guenther Steiner
4 January 1999
Courtesy Ford MotorsportsM-Sport Project Manager Guenther Steiner is the man responsible for overseeing the process that transformed engineering concepts and ideas into the reality that is the all-new Ford Focus World Rally Car. Here he describes the thinking behind Ford's latest challenger for world class rally honours.
Our key philosophy was to start with a clean sheet of paper in order to make maximum use of all the changes in technology, engineering processes and materials that have taken place since the Ford Escort RS Cosworth was created in 1992. In the relatively short time available before the planned competition debut of the Focus, it would have been easy to carry over many proven parts from the Escort. That would have been a short-term solution but ultimately it would have limited the performance and potential of the new Focus for development during the next decade.
Clearly our aim is to win rallies and titles for Ford and we knew that in today's increasingly competitive world we could not afford to compromise. So we forced ourselves to start with nothing, working quite literally on clean sheets of paper as many of our designers still draw their initial thoughts before transferring their ideas onto the computer.
We made everything new and we know that over the next 10 years we can develop both our Focus thinking and our hardware to reach new levels of performance that would simply not have been possible with an Escort-based car. We have big plans to develop the Focus in many areas.
The team focused on the thought 'put the weight where we want it' - that is low down and within the wheelbase to create an agile but more driveable car. And the key to beginning that process was the relationship of the engine and gearbox. From Day One of the project we wanted to use a longitudinal gearbox. A transverse box would have worked, but it has limitations. The longitudinal gearbox can be mounted lower and further back in the chassis, freeing up space in the engine bay which allows us to tilt back and lower the engine, which is mounted transversely, like the Focus road car. The drive from the engine goes through a 90 degree bevel gear and into the gearbox. What's inside the six-speed sequential gearbox is radical and we look forward to revealing more about this in the future - but for now what goes on inside the box must remain a secret.
The gear selector is mounted on the steering rack with the selector lever protruding from the dash board. It is very close to the steering wheel, reducing 'time off the wheel' for the driver's hand. Similar systems have been used in SuperTouring cars and the driver simply pushes to change up and pulls to change down.
In the world of Formula 1 so many of the physical parameters are known that they can be programmed into the design computer and meaningful comparisons of different components can be made - before making the hardware and building the car. In rallying that is just not a practical proposition. So with a rally car, much more of the design process has to be experience-led, not computer pondered.
Our drive to save weight or re-locate weight to the most advantageous positions has led us to make wide use of titanium to make very light, very strong parts. The propshaft, steering rack and much of the suspension is titanium - with a protective coating of nitride which gives it a gold appearance.
A major consideration was the size and location of the fuel tank. We have found a way to accommodate a 100-litre FIA-approved safety tank in the same location as the Focus road car - under where the rear seats would be if a rally car had any - and within the wheelbase. The tank is shaped to allow the propshaft (to the rear differential) and exhaust pipe to pass through. It is protected from damage by ballistic carbon-composite sheeting beneath the car and allows us to keep 90 kilos - the weight of the tank when full of SuperUnleaded petrol - low down and ideally located.
Following the 'no compromise' approach, the engine in the rally car is a 2-litre Zetec E unit, fitted with a turbocharger specially developed by Garrett. Here we took advantage of Ford's worldwide resources to work closely with Garrett to obtain optimum performance from the turbocharger when fitted with the compulsory FIA 34mm intake restrictor. The turbocharger is mounted beside the engine and lower than usual because once again the choice of longitudinal gearbox has created useable space within the engine bay.
The fuel injection system is a new multi-port inlet system which gives a much better throttle response. This is also improved by lower flywheel inertia and extra torque means it spins up to high revs more readily. The engine's torque is distributed via front, centre and rear differentials designed and built by XTrac to Ford specifications. All three are 'active' units and the rear differential is very small, giving exceptional ground clearance.
The basic Focus bodyshell from Ford is already very stiff and the roll cage design which we have incorporated gives a 30 per cent stiffer torsional rigidity than the Escort World Rally Car. Suspension front and rear uses MacPherson struts with many interchangeable parts for ease of service on events and fewer spares to carry. They are fully adjustable units with new ultra-low friction wheel bearings specially developed for the Focus WRC. The suspension geometry gives generous wheel travel which will be particularly advantageous on rougher events such as the Safari. We have not used the innovative 'control blade' rear suspension that works wonders in the Focus road car, because it is unnecessarily complex for a rally car where considerations of noise, vibration and harshness are irrelevant. The brakes are simply the biggest and best we can squeeze inside the wheels.
We are very happy with the aerodynamics of this car. A first we thought we could get away without using a wing at the rear hoping to keep the rallycar and road car looking as similar as possible. The static weight distribution of the rally car is 58% front - 42% rear - compared to 60/40 for the road car. We needed more downforce at the rear. The rear wing we have devised in the wind tunnel will allow us to get nearer to the optimum 50/50 weight distribution when running at high speeds. Even with the wing, the Focus cuts through the air really cleanly and out performs Escort in terms of Cd and downforce over a whole range of speeds.
We have spent a great deal of time in the wind tunnel optimising the aerodynamic efficiency of the car in sideways attitude. We shall need this next year with Colin McRae at the wheel!