1987 Sierra Cosworth RS 500

The switch to Group A rules for the Australian Touring Car Championship allowed Ford to introduce its Sierra Group A racers from Europe. Because demand for an ongoing V8 Falcon had dwindled, Ford Australia had concentrated its development efforts in re-engineering its six cylinder engines which by 1986 were the only family sixes still produced in Australia. A special Group A Falcon V8 was no longer an option after local V8 production ended in 1982.

The Sierra was the European replacement for the Cortina launched late in 1982 and the Sierra RS Cosworth version was first announced at the Geneva Show in March 1985. It was available only as a three door hatch, a body style that had been discontinued from the Sierra range and was now unique to the Sierra Cosworth. Production models followed some time later as the March 1985 announcement was designed to provide advance notice of the new model to private owners and teams.

Ford Australia meanwhile had replaced the Cortina with the locally assembled Ford Telstar version of the front drive Mazda 626. The Telstar had no relationship whatsoever with the rear drive Sierra. While this ruled out any direct connection with the Ford range sold in Australia, the Sierra RS Cosworth race cars allowed the Ford and Holden rivalry to continue throughout the Group A period in Australia.

It was a measure of the Sierra Cosworth that Australia's best drivers including Peter Brock, Allan Moffat and Dick Johnson all drove one at some stage. The Sierra gave Dick Johnson two Australian Touring Car Championships and his 1989 Bathurst win. It also won Bathurst in 1988 with Longhurst and Mezera at the wheel. Global variations in the interpretation of the Group A rulebook ultimately cost the Sierra Cosworth its most emphatic 1-2 Bathurst finish in 1987 some time after the event.

The RS 500 was the evolution version announced on July 22, 1987. It retained the Cosworth twin cam 16 valve head but its Cosworth YBD-series engine was based on a new reinforced version of the Ford 2-litre four cylinder cast iron block. Most components were tweaked for extra performance and durability under racing conditions when this engine was often delivering 300 kW. The induction system was boosted from 56 to 65mm diameter, the intercooler was much bigger, there were now twin injectors per cylinder and a new water-cooled hybrid Garrett-AiResearch turbocharger was specified.

Cosworth cast the head at their own casting works then machined and assembled it at another Cosworth facility. The whole engine was hand-assembled and individually tested by Cosworth. Suspension and brakes which included Teves four piston front calipers continued as for the Sierra Cosworth.

Externally, the RS 500 had an extra cooling slot at the front while the fog lights were replaced by brake cooling grilles. The front air dam had a more pronounced lip which extended around the lower bumper corners to form an aerodynamic splitter. At the rear, a 30 mm lip extension on the rear wing and an additional liftback spoiler generated an extra 100 kg of downforce at 160 km/h. In road trim, the engine delivered 167 kW for a homologation top speed of 153 mph.

Tickford UK was commissioned by Ford to homologate the RS 500 for production and final assembly. This was carried out under the supervision of manufacturing director, David Flint, better known in Australia as the founding managing director of Tickford Vehicle Engineering and Ford Performance Vehicles. This rare Sierra model has a valid place in Australian Ford performance history as a significant winner.

Examples of the Sierra Cosworth and the later Sapphire version which was more of a mainstream Ford model are well-represented in Australia after reaching here as private imports. A similar model was developed in South Africa but featured the 5-litre Windsor V8 instead of the Cosworth engine. This Sierra V8 was called the XR8 some time before the XR8 nameplate appeared in Australia on a Falcon-based model.