Sierra RS Cosworths

The abbreviation RS stands for Rally Sport. It denoted hot versions of the Ford Fiesta, Escort and Sierra. For less hot versions of these cars Ford used the designation XR. The name Cosworth indicates that their engines were designed by Cosworth Engineering of Northampton, a company founded by Mike Costin and Keith Duckworth, who set up shop in northern London in 1958 after having met at Lotus. This company now belongs to Volkswagen AG.

Sierra RS Cosworth two door

Manufactured by: Ford of Europe, Genk, South Limburg, Belgium
Years produced: 1986
Price at launch: £15500

To render the Ford Sierra competitive in motorsports, it was decided to use a turbocharged 2-litre twin cam version of the Pinto engine. This made use of an aluminium head, cogged belt drives, a Garrett TO3 turbocharger, an air-to-air intercooler and a Weber-Marelli engine management system. As Ford’s Type 9 gearbox was not considered adequate, it was decided to use an American built 5-speed Borg-Warner T5 instead. For homologation purposes it was decided to produce 5000 such cars for sale to the public. With the RS Cosworth the power output of this engine was 204 HP.

Originally the intention was to use a four-pillar XR4 bodyshell, but due to the disappointing sales of the XR4i the conventional two-door Sierra’s three-pillar shell was used. To this were added a front-end chin spoiler, wheel arch extensions and a sizeable rear wing which was propped up with a central pylon on the tailgate.  This provided downforce at speed, which affected its high speed handling in a favourable manner. Only three exterior colours were available: Diamond White, Moonstone Blue and Black.

A total of 5542 Sierra RS Cosworths were produced, all in the second half of 1986. About half were sold in the UK. Other markets were Western Europe, where this car found favour especially in Austria, and a total of nine found their way to the Canary Islands, the U.S.A., Australia, Hong Kong and New Zealand. None were sold in Sweden, Denmark or Yugoslavia.

Sierra RS 500 Cosworth

Manufactured by: Ford of Europe, Genk, South Limburg, Belgium and Aston Martin Tickford, Bedworth, UK
Years produced: 1987
Price at launch: £19500 

The RS500 Cosworth was the ultimate performance Sierra. In racing it was so successful, it came to dominate the World Touring Car Championship and the European Touring Car Championship and many national championships. As 5000 examples of a car had to be sold for homologation purposes, and an additional 500 modified examples could be built, the previously mentioned RS Cosworth was used for homologation. The name RS500 was agreed upon as it had been decided to build 500 examples of this modified car, and not one more or less.

From the production line at Genk in Belgium 500 Sierra RS Cosworths were taken and sent for modification to Aston Martin Tickford at Bedworth, near Coventry (a company which, despite its name, is not connected to the famous Aston Martin of Newport Pagnell, now part of the Ford group), which had already been known for building the turbocharged Tickford Capris. All these were right-hand drive versions, as this car was intended only for the British market. Modifications included a Garrett TO4 instead of TO3 turbocharger, twin fuel-rail/eight-injector fuel injection, modified and enlarged inlet passages, recalibrated electronics, suspension and aerodynamic modifications. Its power output had increased by 20 HP to 224 HP. Versions modified for racing were known to generate some 350 HP, and some even managed a whopping 550 HP.

Production took place in the months of June and July 1987. By that time the second generation, or facelifted Sierra had been introduced. Thus the RS500 Cosworth was the only first generation Sierra to be sold after the introduction of the second generation of this model. Its price was £19500. Such cars were susceptible to theft, and several RS Cosworths were slightly modified and sold as RS500 Cosworths. Therefore Ford made the Aston Martin Tickford build list available, so that the veracity of the RS500 could be checked. Such cars could be sold for £30000 on the used market. The acceleration of the RS500 Cosworth was inferior to that of the RS Cosworth at low speeds, but its top speed was 5 mph faster. All in all, the RS Cosworth was more suited to daily use, as the RS 500 had a larger turbocharger which did not start to operate until the engine reached 3000 rpm. This rendered it more suitable for racing.

Sierra RS Cosworth four-door

Manufactured by: Ford of Europe, Genk, South Limburg, Belgium
Years produced: 1988 - 89
Price at launch: £19000

Sales of the four-door RS Cosworth commenced in the beginning of 1988 and lasted until the end of 1989. Initially its price in the UK was £19000, and it increased to £21300 by the time production ended.  A total of 6670 were built. The primary markets were Western Europe, especially the UK and Italy, and some were sold in places like Hong Kong, Singapore, the Canary Islands, Macao and South Africa. None were sold in Sweden, Switzerland, Austria or Yugoslavia.

Sierra RS Cosworth 4X4

Manufactured by: Ford of Europe, Genk, South Limburg, Belgium
Years produced: 1990 - 92
Price at launch: £24995

Even before the original Sierra RS Cosworth two-door had been launched Ford considered a four-wheel drive version of this car. Use could be made of the running gear of the Sierra XR4x4. However, its Type 9 gearbox was not capable of handling the Cosworth engine, and the Borg-Warner T5 gearbox could not be fit on the running gear of the XR4x4. Therefore Ford had to await the introduction of its MT75 (Manual Transmission, 75 mm between the shafts) gearbox, which was suited for front-wheel, rear-wheel and four-wheel drive.

The engine of the Sierra RS Cosworth 4x4 was modified, resulting in a power output of 220 HP. This engine valve seats were made such so it could run on unleaded fuel. As the weight of this car increased by 210 lb (96 kg) due to the extra differentials and drive shaft, performance remained virtually unchanged. Viscous couplings were used in the centre and rear differential, but not in the front, and the torque split was 34% at the front and 66% at the rear wheels. Visually the RS Cosworth 4x4 was identical to the four-door RS Cosworth except for the louvers on the bonnet and 4x4 badges on the front fenders.

Deliveries of the Sierra RS Cosworth 4x4 commenced in the spring of 1990, and in the UK the RS Cosworth 4x4 cost initially £24995. Its principal competitor was the Mercedes-Benz 190E 2.5-16, which also had a Cosworth designed engine, and cost in the UK £ 32940. Production of this car continued until the Sierra was phased out in 1992.