Cosworth is a name that's been at the forefront of performance engineering for over 60 years, dominating everything from Formula 1 to touring car racing. This success wasn't just forged on the track, however, with Cosworth part responsible for some road-going icons, too. At the core of this, though, were fast Fords — and, more specifically, the car that arguably launched this into the mainstream: the Sierra RS Cosworth.
By the time of the car's launch in 1986, Cosworth and Ford were no strangers to each other. In fact, they were far from it, as Cosworth had been tinkering with Ford engines dating back to 1959. Racing played a big part in their partnership, then, and unsurprisingly, the Sierra Cosworth followed suit. It was a proper homologation car designed to hit the tracks since Group A regulations meant that 5,000 units needed to be built. Cosworth provided Ford with a 16-valve twin-cam engine derived from their very own Pinto, with plans to throw a whopping turbo on there, too. The Sierra, which was already powered by the Pinto, was chosen as the foundation to work with, turning the conservative family car into an aggressive, race-winning machine.
Let's take a detailed look at the Ford Sierra RS Cosworth and what made it so iconic.
The History Of Cosworth
Cosworth was founded in 1958 in Northampton by Mike Costin and Keith Duckworth. They both worked for Lotus at the time but wanted to start their own racing-focused company. Costin, who had just extended his contract with Lotus, was required to continue working for the company until 1962, meaning only his spare time could be spent working for Cosworth. They launched their first racing engine in 1959, which also marked the beginning of Cosworth’s involvement with Ford. The engine was derived from the Ford Anglia 105E and was to be used in the back of the Lotus 18 — as, at the time, Cosworth was still being heavily funded by Lotus. The engine was reworked by Cosworth to develop 75 bhp and, at its best, broke the 100bhp per liter mark with 123 bhp. The result was a great success, with the engine dominating in Formula 2, 3, and Junior. The best, however, was yet to come.
Having cut its teeth in the lower rankings, Cosworth then fancied its chances in the big leagues. Cosworth had been contacted by Lotus in 1965 to develop a 3.0-liter engine for Formula 1. Lotus, who were then closely affiliated with Ford, managed to secure over $100,000 worth of funding for Cosworth. In 1967, the engine was complete. And what an engine it was. It was named the DFV, which was a naturally aspirated, 2,993 cc V8 producing 408 bhp and 270 lb-ft of torque. The engine was an instant success, having secured victory at the Zandvoort circuit on its first outing. But it didn’t stop there. It went on to become the most successful Formula 1 engine of all time, eventually securing 176 wins and featuring across 55 different teams.
A Detailed Look At The Sierra RS Cosworth
With such a huge racing pedigree behind it, then, you'd expect the Sierra RS Cosworth to have a bit about it when it came to performance. And there were definitely no disappointments. The first generation Sierra Cosworth — or "Cossie", as it was known to fans — came with a 2.0 liter, Pinto-derived four-pot, with an aluminum twin-cam head, a Garrett AiResearch T3 turbo and an intercooler added. It also came with a five-speed Borg-Warner gearbox as standard and sent torque to the rear axle using a viscous coupling limited-slip differential. The result was 204 bhp, 205 lb-ft of torque, and a 0-60 time of 6.2 seconds, figures that were then nipping at the heels of your typical supercar. In race form, power eventually increased to over 500 bhp, and the Sierra dominated touring car championships winning 84% of races it entered.
The looks were just as exhilarating, too, thanks to that famous "whale tail" spoiler and those iconic bonnet vents. The body kit was borrowed from another Ford — the Murker XR4Ti, which was sold exclusively in the US — to improve aerodynamics over the standard Sierra. This look was said to be frowned upon by officials at Ford, with sales initially predicted to be around the 1,500 units mark. A total of 1,600 were sold in the UK alone, though, with over 6,000 sold in total, and that was largely due to the car having power that was typically reserved for the rich, at a cost available to the masses. New, it was priced at around £16,000 — which is around $22,000, though the car was never actually sold in the US — which meant you didn't need to be a millionaire to have one in your driveway.
A limited run of 500 cars was developed in 1987, too, as Ford wanted to modify racing versions but needed to meet further regulations. They were aptly named the RS500, with an additional fin on the rear spoiler, a modified front skirt to improve airflow, and subtle RS500 badges added. A bigger turbo and a revised inlet manifold increased power by 20 bhp, too, and there was also a secondary injector system laying dormant for use on race versions.
In 1988, Ford shedded the homologation status of the Sierra Cosworth, instead focusing it more for use on the roads. The second generation was based on the four-door Sapphire and took on a much more muted look, but it was marginally quicker to 60 than its predecessor and had the same 204 bhp — though this figure may seem small compared to modified versions, admittedly. In 1990, having wanted to take the Sapphire rallying, Ford created the third generation, four-wheel-drive version, and uprated power to 217 bhp. It didn't quite have the racing success of the first generation, though, but still managed podium finishes in 1990 and '91 before bowing out to another rallying icon in '92, the Escort RS Cosworth.
Sources: Hagerty, Wikimedia Commons, Cosworth