The Ford Sierra RS Cosworth is a high-performance version of the Ford Sierra that was built by Ford Europe from 1986 to 1992. It was the result of a Ford Motorsport project with the purpose of producing an outright winner for Group A racing in Europe. Mike Moreton was head of the team that planned to develop an evolution edition aimed at making the car unbeatable on the race tracks. In March 1987, Aston Martin Tickford was signed for the job of converting the 500 cars. The Cosworth RS500 was announced in July 1987, and was homologated in August 1987.The main difference to the Sierra three-door Cosworth was Cosworth's uprated competition engine. Its new features were: The Inline-four engine had a thicker walled cylinder block to cope with the rigours of the track. A larger Garrett AiResearch T04 turbocharger A larger air-air intercooler A second set of four Weber W025 yellow" fuel injectors and a second fuel rail (not activated in the roadgoing version). An uprated fuel pump. A reworked induction system to allow higher power outputs to be realised. An uprated oil and cooling system. The rear semi-trailing arm beam had extended but unused mounting points. Engine output increased to 227 PS (224 hp; 167 kW) at 6000 rpm. . torque of 277 N⋅m (204 lb⋅ft) at 4500 rpm.[3]. The RS500 also had minor external cosmetic differences to its parent the Sierra three-door Cosworth: The rear tailgate had a lower spoiler in addition to the upper "whale tail" Discreet RS500 badges on the rear tailgate and front wings A redesigned front bumper and spoiler to aid cooling and air flow, including the removal of the fog lamps and their replacement with intake grilles to supplement brake cooling
