Background
The badge ‘Cosworth’ has always been synonymous with performance, and when Ford chose to apply the legendary badging to its line of performance Sierras in the 1980s, they were a predictable success, bringing supercar-beating performance to the masses, with a mind-boggling level of customisation and tuning at the hands of any owner.
Not only was there plentiful tuning opportunities, but also extensive knowledge thanks to an impressive enthusiast base - the chief of which was the renowned RS owners club - and, unfortunately for the owners, a somewhat ill-deserved reputation for fast Ford owners being somewhat flippant when it came to following the letter of the law, though this has largely died out in this modern world of social media, ANPR and automatic speed cameras.
Beginning with an otherwise-unassuming family three-door hatchback, Ford built the Sierra RS with the outright goal of producing a Group A motorsport winner, with Stuart Turner at the head of the table.
By replacing the mundane performance offered by the standard Sierra’s engine with the incredibly tuneable turbocharged YBB block and mating it to a custom-built Borg-Warner manual transmission, Ford were on to a winner.
Underneath, the suspension and chassis were largely influenced by Andy Rouse and Jack Roush and their successful motorsport campaigns in IMSA and BSCC respectively, though numerous production parts from the XR4Ti also found their way underneath the Sierra Cosworths’ bodywork.
Demanding ‘carte blanche’ in order to keep the car stable at high speed when designing the RS Cosworth’s bodywork, designed Lothar Pinske based the body on the XR4i, but incorporated some subtle design changes, and - of course - added the absolutely, not-at-all subtle trademark ‘whale tail’ rear wing, which was necessary for high-speed stability and ground contact.
In the end, a total of 5,545 Sierra RS Cosworths were built, with 500 of these being sent to Tickford for conversion into the even-rarer RS500 models for homologation purposes.
To this day, the iconic ‘Cosseh’ enjoys something of legendary status among both the Ford fraternity and the car enthusiast scene as a whole, whilst extensive tuning and somewhat inexperienced drivers mean that finding a good, non-accident-damaged car is becoming harder and harder.







