FORD NEWS RELEASE THE FORD RS COSWORTH IN DETAIL The origins of the new RS Cosworth go back to 1988 when Ford established a new five year plan for its motorsport activities. Central to this was World Championship rallying in which the company was such a dominant force during the 1970s with the Mkl and Mk2 Escort - winning the Championship title in 1979. Formidable competitor Through the 198O's, the Sierra RS Cosworth in both 2WD and 4x4 form has proved itself a formidable competitor in rally sport, but to compete successfully in the 1990s at the highest level internationally, Ford Motorsport recommended the development of an Escort-sized vehicle, where retaining the power train and vehicle layout of the well-balanced Sierra Cosworth. A concept car along these lines was built by Ford Motorsport at their Boreham facility in the UK as a first step. Then, once programme approval had been granted, development for production was taken over by SVE (Special Vehicle Engineering), the department which has engineered all Ford's current generation RS models. International rallying is run to Group A regulations which demand a minimum 5,000 units to be built in one year before a car can be homologated for competition use. (This figure reduces to 2500 units in 1993). Fully-fledged production model However the RS Cosworth is no mere 'homologation special'. From the start it was determined that the car would go in to full scale production and that the road going version would have to meet the same exacting standards as any other Ford model. SVE's task therefore. was to turn that single prototype into a fully fledged production model and the team has done this in just two years - astonishingly fast for what is in most respects an all-new vehicle. The goal has been to produce not only a potential rally winner but a road car that is reliable, refined and safe as well as offering unmatched driver satisfaction. o Aerodynamcs-first production car with positive downforce Aerodynamics are of the greatest importance in both motorsport and for a high performance road car. SVE's prime objective for the Escort RS Cosworth was to create a moderate level of down force with emphasis being given to achieving a balance between front and rear in order to improve grip and stability at high speed. However, the spoilers that create this down force also increase drag so their size and shape has to be chosen with care. An additional problem was posed by the turbocharged engine which demands considerable cooling airflow - particularly under competition conditions - and therefore also increases drag. Extensive aerodynamic development These conflicting requirements were resolved during some 200 hours detail development in Ford's own Cologne wind-tunnel. The result is almost certainly a world first: a production car which generates positive down force (or negative lift as it is sometimes known) at both front and rear. In fact the RS Cosworth generates 45 Newtons of down force at the nose and 190 Newtons at the rear at 180 km/h. The downforce is created by a sophisticated arrangement of front and rear spoilers. At the front is a conventional air dam type spoiler below and integral with the bumper. In addition small spats run around the wheel arches at the edges of the spoiler and an aerodynamic 'splitter' is fitted at its base. The spats serve two roles: they give additional surface area to the front spoiler to increase down force and also help deflect the airflow out and away from the front wheels which reduces drag by approximately ten per cent. Aerodynamic splitter The aerodynamic splitter - so called because its function is to split the airflow above and below the car - is adjustable to three positions the most forward of which is ideal for circuit use. The further forward it is located the greater the down force (the figures above were recorded with the splitter in its middle position) . At the rear, the large spoiler at the top of the tailgate is an obvious source of down-thrust but the smaller lower spoiler is equally important while the distance between the two spoilers is crucial in determining down force and was fine-tuned at some length in the wind tunnel. New production process The large rear spoiler is manufactured by Resin Transfer Moulding (RTM) a process which is new to Ford. Polyester mat is laid into mounds to form the top and bottom halves of the spoiler: these are then closed around a centre core of polyurethane foam and resin is injected around the core. The result is a tough and very high quality glass reinforced plastic skin which is just 1.5 mm thick - far thinner than could be obtained by traditional moulding methods and a saving of around 50 per cent in weight compared with a conventional polyurethane spoiler The aerodynamic drag effects of engine compartment cooling are minimised by the use of a fully ducted cooling system. Air is channelled through the radiator and around the engine escaping via specially shaped bonnet louvres, further louvres at the rear edges of the front fenders and from under the rear of the engine. An under-body tray below the power unit manages this airflow and also reduces exterior noise levels. Despite the additional spoilers and with the cooling drag penalty increased from 0.016 Cd on the standard car to 0.035 Cd, careful smoothing of the exterior shape of the RS Cosworth has resulted in a final drag factor of 0.38 Cd. which compares favorably with the standard Escort's 0.34 Cd. o Bodyshell - exceptionally rigid and strong Overall some 50 per cent of the RS Cosworth's body panels are new, while the remainder are derived from existing Escort and Sierra components. The fuel tank is blow-moulded plastic which enables the tank to be shaped to fill the space available. Its space-saving properties have allowed a useful 65 litre capacity (compared with the standard Escort capacity of 55 litres). it also features a latest technology in-tank fuel pump. Body engineering was a joint exercise by SVE and by Karmann who are manufacturing the vehicle. The front wings and rear quarters are wide to accommodate an increased track and larger wheels. The rear body sides have also been raised by some 30 mm to carry the lower spoiler at the correct position. Overall the RS Cosworth is 175 mm longer 50 mm wide and runs on a 26.5 mm longer wheelbase than the standard Escort. Finite element analysis The RS Cosworth bodyshell has exceptional torsional stiffness - 6 000 Newton meters of torque are needed to produce one degree twist in the body. Extensive rig testing and finite element analysis studies were carried out before the body's design was finalized to provide the ideal characteristics, the only additional reinforcements needed to improve rigidity were plates between the turret tops and the inner wings. o Engine - latest version of turbocharged Cosworth power unit The 2.0 litre 16-valve turbocharged YBT engine of the Cosworth is broadly similar to the YBG unit of the Sierra RS Cosworth. However there have been a number of significant changes made. Most important of these is the fitment of a new and larger Garrett T3/T04B turbocharger with a two-stage inter cooler. The turbocharger is a special hybrid unit which combines the turbine of the T3 with the compressor of the larger T04B. It has been developed to provide good on-road driveability together with the increased power potential needed for competition usage. Two-stage intercooler The two-stage inter cooler is another feature developed with motorsport in mind. The charge air passes through a water cooled matrix before passing through a further air cooled matrix to give substantial additional cooling of the intake air. A further development of the Weber-Marelli fuel injection and engine management system has been used. The new unit now has full closed-loop control of turbocharger boost. In other words the boost characteristics are constantly compared to pre-mapped settings and adjusted accordingly. This change has enabled an element of 'over-boost' to be designed in to the system, which allows the engine to run higher than its standard 0.8 bar boost for short periods. The precise over-boost characteristics have also been calculated and mapped. Other engine changes include a lighter flywheel to reduce inertia and allow the use of a competition multi-plate clutch, retuned engine mounts to minimize NVH transmission, a redesigned cam belt cover, improved oil baffles for the sump and a blue painted cam cover to denote the new engine type. Maximum power of the YBT engine is 227 PS (DIN) at 6,250 rev /min with maximum torque of 304 Nm (DIN) at 3,500 rev/min. o Suspension, steering and brakes - tuned for safety and driver satisfaction Suspension steering and brake components are broadly similar to those of the Sierra RS Cosworth. However considerable development work has been carried out to achieve the best results for the new model. From day one, the RS Cosworth suspension was developed with the aim of improving on or matching the standards set by the car's rivals. SVE's own engineers and an impressive array of racing and rally drivers were called upon to make direct head-to-head comparisons between the Ford and its competitors both on the road and around the Nurburgring racing circuit. Precise handling characteristics From these early evaluations it was determined that the RS Cosworth should have minimal cornering roll, precise steering, outstanding high speed cornering stability and carefully controlled compliance in the suspension bushes to provide positive and responsive handling. To control compliance new suspension bushes with bi-directional characteristics have been incorporated in the rear cross member mountings and differential mountings. Rather than being the usual plain rubber design these bushes have steel plate inserts which reduce their ability to compress in one direction only. As a result. they retain the longitudinal compliance necessary for comfort but reduce lateral compliance to prevent the rear suspension assembly moving in relation to the car during cornering. Further measures to optimise the handling characteristics include stiff front suspension top mounting bushes and rigid rear semi-trailing arms which prevent any chance of flexing under extreme loads. The mounting points for the trailing arms on the rear cross-member have been specially reinforced. The front anti-roll bar is 28 mm diameter and at the rear is a 22 mm anti-roll bar. Gas-filled dampers are fitted all round. Specially formulated tyres Tyres for the new RS Cosworth were chosen after a year long appraisal programme which involved subjective evaluation on the road race circuit testing and as a primary requirement excellent wet weather grip. The tyres finally chosen were a version of Pirelli's P Zero specially formulated by the company for the car. They are size 225/45ZR16 and are mounted on 8 x 16 inch five-spoke alloy wheels . Power assistance is standard for the steering and a new power steering pump with revised flow characteristics gives precise steering response and excellent feel. The braking system comprises 278 mm front and 273 mm rear ventilated discs with hydraulic assistance and ABS electronic anti-locking. The front brake calipers are particularly rigid, front brake pad area is generous for an extended service life and disc design has been developed to optimise cooling. The pad material has been chosen to give the best possible high temperature performance. With motorsport in mind cooling ducts have also been built in to the front spoiler assembly. Refined ABS braking The control logic of the Teves Mk 2 ABS has been developed to give sensitive anti-locking control. This is aided by an additional mercury switch type deceleration sensor. The ABS developments have allowed the viscous couplings, used to limit slip in the centre and rear differentials to be made stiffer without any sacrifice in anti-locking performance which gives benefits to cornering grip particularly in poor surface conditions. o Interior - unique instrumentation and high equipment levels Unlike previous RS Cosworth models the new RS COSWORTH has its own, unique instrumentation. The main instrument pack is similar to that of the Escort RS2000 however a panel of three auxiliary gauges - for oil pressure, turbo boost and battery voltage - is housed in a new binnacle located at the top edge of the facia. The instruments themselves are new, too. Not only are the dials black on white but they also feature a unique new form of instrument lighting, electro-luminescence. This has been used in a slightly different form on the Aston Martin Virage but is otherwise unique to the car industry being derived from aircraft instrumentation. In this system there is no conventional instrument lamp; instead the surface of the instrument itself glows green. This effect is achieved by using a composite material for the surface which includes a phosphor-coated layer. A 115 - 120 volt AC current is applied to this layer which causes it to glow. (The AC current is created from the normal 12 volt DC battery voltage by a small inverter at the rear of the instrument). The result is even instrument illumination which automatically adjusts for ambient light conditions. Unique interior features The interior of the RS Cosworth is derived from that of other Escort models but has a number of unique features including a new style three-spoke leather-rimmed steering wheel with horn buttons on the side spokes as well as the hub, a separate centre console and a luxurious rear seat. The standard front seats are unique to the RS Cosworth and provide excellent comfort over long distances combined with positive lateral support. More sporting body-hugging Recaro seats are either optional or standard equipment according to the market concerned. Extensive standard equipment Standard equipment for the luxury model includes power windows powered and heated door mirrors, Premium radio/cassette unit a heated front screen heated screen washer jets, headlamp wash, glass sunroof, central locking and remote boot release, opening rear quarter windows, door bins, rear seat head restraints and central armrest and a centre console with armrest and cassette stowage. All these items are deleted in the Road Sport version of the RS Cosworth which is intended primarily for those who want to buy the car with competition usage in mind. This model features Recaro seats as standard, manually-operated windows and door mirrors and fixed rear quarter windows. Options on the luxury model include metallic paint Recaro seats, seat heating, air conditioning, a CD player and leather trim. o Testing and manufacturing The RS Cosworth has been through the same demanding pre-release testing programme as any other Ford model and, in addition has had to undergo the tough programme required to develop it for motorsport use. Following on from the original concept vehicle, there have been a total of 12 prototype road cars, two motorsport cars and four more rolling chassis. After these came three pre-functional build cars and ten more functional build cars before some 50 cars went into pre-production assembly. Exhaustive test procedures The Cosworth has gone through Ford's own General Durability test procedure no less than four times. This is a rigorous 40,000 km-long testing programme undertaken at the Company's Lommel proving ground. In addition it has also been put through the Improved Durability programme, a more severe version of this procedure. The effects of the General Durability test circuit have also been simulated on a special hydropulse test rig. Data is collected to show the movements of each road wheel during General Durability testing and these can be replicated on the special rig at the Company's research centre in Dunton.