When it comes to developing or selling road cars, many manufacturers love getting involved in some sort of racing series. Pounding a car around a track or rally stage for hours on end puts demands on a vehicle that cruising along a road simply can’t match, allowing engineers to find weaknesses with their creations that can then be ironed out for the road. Plus, the whole ‘Win on Sunday, sell on Monday’ adage came into play, as spectators who supported a certain driver, car, or manufacturer would be more likely to purchase a road-going version having witnessed it racing.
Ford has always been a big exponent of this approach, and one of its 1980s challengers was so hardcore that it was designed to carry a factory roll cage from the outset.
The Sierra RS Cosworth Was Built To Solidify Ford’s Racing Heritage
1987 Ford Sierra RS Cosworth Silver Front Angled View Lights OnBring a Trailer
The machine in question is the Ford Sierra RS Cosworth, which was dreamed up by Stuart Turner, then Ford’s Head of Motorsport, in 1983. He felt that Ford wasn’t sufficiently positioned as a big player within racing, with the manufacturer’s successful earlier sports car and rally programs long in the past. The evolving Group A regulations were chosen as the ideal arena for Ford’s racing push, as the cars not only looked like their road-going counterparts, but the category was also gaining popularity by the year. World-famous series like the British Touring Car Championship and the World Touring Car Championship used the regulations, while rally cars could also be fashioned using them.
1986-1987 Ford Sierra RS Cosworth
Engine
2.0L turbocharged I4
Transmission
5-Speed Manual
Power
201-220 hp
Torque
205-206 lb-ft
0-60 mph
6.1-6.2 seconds
Average Used Value
$64,606-103,028
Turner elected to use the Sierra sedan due to its aerodynamic shape and rear-wheel drive layout, while longtime Ford partner Cosworth was tapped to develop a new turbocharged engine for the machine. Following a three-year development program that used a three-door version of the car, which featured a wild new aero package to help keep the car pinned to the road, the production version was unleashed in 1986. Since Ford wanted to take it Group A racing, a total of 5,000 road cars had to be produced alongside the race-prepared variants.
It Used The Bones From An American Performance Sierra
1987_merkur_xr4ti front redBring a Trailer
While the Sierra RS Cosworth was a Ford of Europe project, which meant it was never sold in the United States, it did make use of parts from its American counterpart. The Merkur XR4Ti was essentially a rebodied version of the Sierra XR4Ti, a turbocharged mid-range performance variant of the model. These parts were borrowed because it meant Ford didn’t need to homologate them for use within the vehicle, as they were already utilized in a road-going car.
The Merkur couldn’t get near the performance of the full-fat Sierra RS Cosworth, though, leaving American enthusiasts frustrated that they couldn’t get a taste of this particular Fast Ford.
The Sierra Cosworth Could Really Shift
CNC Motorsport Ford Sierra RS500 Group A ContinuationCNC Motorsport
In road car spec, the Sierra RS Cosworth produced a handy 201 horsepower from its turbocharged 2.0-liter Cosworth inline-four engine, which was derived from Ford’s Pinto family of powerplants. The Pinto was chosen as the basis for the new engine since the standard Sierra was already offered with it, which ensured it would be easy to install. A five-speed manual transmission delivered the engine’s grunt to the rear wheels, while a limited-slip differential was on hand to allow the tires to transfer the grunt to the road without losing traction. This was especially handy on the Group A racers, as these got tuned versions of the engine that produced around 400 hp early on, before eventually being developed to produce well north of 500 hp in the late 1980s.
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The Sierra’s chassis was left largely untouched, but a few alterations were made to ensure it handled like a proper pocket rocket. A quicker steering rack was added, while the Sierra’s spring rates, dampers, and anti-roll bars were tuned to provide more responsive and agile handling. Needing to keep the machine competitive in the late 1980s, Ford later developed a special version of the car called the RS500. It got an upgraded version of the engine that produced 220 hp, while also getting an even more hardcore body kit and a revised rear suspension setup that allowed for greater versatility when tuning the rear end of the vehicle.
The Car Could Be Purchased From Ford With A Rollcage
1987 Ford Sierra RS Cosworth Group A cockpit viewIconic Auctioneers
Given the close relationship between the road and race versions of the RS Cosworth, it shouldn’t come as a surprise to learn that you could purchase a Group A competition variant as easily as you could a production version. The homologated race gear, such as a tough rollcage to prevent the car from crumpling in the event of a crash, was designed to easily fit within the confines of the RS Cosworth from the factory.
That meant teams or individuals could purchase a road-ready Sierra RS Cosworth from Ford or its associated tuners, since the rally-spec variants of the vehicle had to be road legal so that they could travel to each rally stage without being transported everywhere. As a result, you could technically use a Group A rally version of the RS Cosworth as a daily driver, but its stripped-out nature meant that actually doing this would be extremely uncomfortable. In fact, you’d probably come out more relaxed from the latter.
A Used Sierra RS Cosworth Is Pretty Expensive
1987 Ford Sierra RS500 CosworthBonhams
Given that the road-going Sierra RS Cosworth was built purely to allow Ford to take on its rival manufacturers in Group A racing, as opposed to maximizing profits from a sales standpoint, it never built a ton of road cars. In total, 5,500 RS Cosworths were produced and sold across Europe, with a further 500 cars built to the later RS500 spec. As a result, they’re one of the rarer Ford performance models out there, and given their racing heritage, their used value stands pretty high today.
According to Classic.com, the average auction sale price for the standard version currently stands at a commanding $64,606, with low mileage and mint examples attracting around $100k at the moment. As the number of low-mileage examples decreases and the car ages, expect values to comfortably breach this level before too long. The faster and rarer RS500 demands even more from your wallet, with it selling at an average of $103,028. Specimens in concours condition have sold for as much as $175k, illustrating just how appealing they are in 2026.
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Ford’s Wild Racer Didn’t Gain Much Of A Reputation Across The Pond
Thanks to the 25-year import rule, Sierra RS Cosworths have been eligible for import into the US for years already. Despite this, they’re not particularly popular stateside, but then this isn’t exactly surprising. The fact that it was never sold in the US meant it was largely segregated from American gearheads in its prime, so it simply never achieved such a revered reputation there as it did in Europe. Plus, Group A racing never really took off in the US, so it’s not as if the Sierra lit up American racetracks, either.
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The Sierra RS Cosworth Remains A European Racing Legend
CNC Motorsport Andy Rouse Engineering Ford Sierra RS500 Group A Touring CarAston Parrott/CNC Motorsport
Across the Atlantic, the Sierra RS Cosworth is still remembered as one of the coolest tin-top racecars ever produced. It’s not hard to see why, especially when you watch old footage of the car drifting around the world’s best racetracks as the fearless drivers desperately try to keep the 500+ hp beast under control. The BTCC in particular was becoming more popular in the late 1980s too, with many race fans witnessing close and thrilling battles between touring car greats such as Andy Rouse and Tim Harvey.
In addition, the car found success competing in rallying across the world. Once the Group B era came to an end in 1987, Ford made use of the Sierra RS Cosworth due to the Group A regulations being brought in to replace Group B. While it lacked the pace of the four-wheel-drive cars on mixed surface rallies, the Sierra was a force to be reckoned with on tarmac. It managed to claim a solitary World Rally Championship victory in the 1988 Tour de Corse, with future WRC champion Didier Auriol behind the wheel. Eventually, Ford replaced the RS Cosworth with the Sierra Sapphire, which was equipped with 4WD.
The machine certainly left its mark on gearheads around the world, whether it was on the road or via the world’s racetracks or rally stages. The Sierra RS Cosworth is a great example of building a car to be successful in competition first, before adapting it to work on the road. Models like the Toyota GR Yaris follow this recipe today, but few models have managed to claim supremacy in circuit racing and rally the way the old Sierra RS Cosworth managed.
Sources: Classic.com, Ford.
