There are sensible ways to improve the image of a family car, and then there’s bolting a vast rear wing to it and sending it racing. Ford, gloriously, chose the second option.
The Sierra hadn’t exactly enjoyed a gentle introduction when it arrived in 1982. Its aerodynamic “jelly mould” styling looked futuristic to some and faintly alarming to others. Plenty of buyers were still emotionally attached to the Cortina, which had the comforting shape of something that knew how to queue properly. The Sierra was smoother, rounder and wind-tunnel-friendly, but early on it had a bit of an image problem.
Then Ford Motorsport got involved, and image problems became the least of anyone’s worries.
By the mid-1980s, Ford wanted a serious weapon for Group A touring car racing. The old Capri was ageing, the RS200 rally project was about to be caught up in the end of Group B, and touring cars offered a very public way to make the Sierra look exciting. The problem was that Group A rules demanded a production base. If Ford wanted to race a monster Sierra, it first had to build thousands of road-going ones.
The idea was driven by Stuart Turner, Ford’s motorsport boss, who knew Ford needed proper power and proper credibility. Cosworth was the obvious partner. The Northampton engineering firm took Ford’s 2.0-litre four-cylinder engine architecture and created the turbocharged, 16-valve YB unit that would become the stuff of fast-Ford folklore. It had the right badge, the right noise, the right boosty temperament and, crucially, the right potential for racing.
There was just one awkward detail. Ford had to commit to a lot of engines. According to one well-worn version of the story, Cosworth wanted a 15,000-engine agreement, while Ford only needed 5,000 cars for homologation. That left Ford with a slightly terrifying business case: build a very aggressive, expensive-looking Sierra and hope people bought it.
The dealers weren’t universally convinced. Some reportedly thought Ford would struggle to sell even 1,500 of the things. In fairness, you can see their point. This was a three-door Sierra with a big turbo engine, a bodykit and a rear wing large enough to host a modest buffet. It wasn’t exactly the obvious choice for someone popping in to ask about finance on a 1.6 Laser.
But the wing wasn’t there for theatre. Well, not only theatre. The standard Sierra’s slippery shape created lift at high speed, which isn’t ideal if your racing car is meant to stay attached to the planet. Lothar Pinske in Ford’s Special Vehicle Engineering team worked on the body modifications, and the now-famous “whale tail” was part of the aerodynamic solution. Sales people may have winced, but the engineers needed it.
And thank goodness they won. Without that rear wing, the Sierra RS Cosworth would still have been quick. With it, it became unforgettable.
Launched for sale in 1986, the road car looked like nothing else in the office car park. It had the stance of a Sierra that had been told a secret about motorsport and taken it personally. Underneath, it was rear-wheel drive, turbocharged and far more serious than its family hatchback roots suggested. Ford built 5,545 three-door RS Cosworths, enough to satisfy the Group A requirement and create the base for the even more focused RS500.
And the RS500 is where the story gets properly spicy. Built in 1987 as a 500-car evolution model, with conversions handled by Tickford, it gave Ford the extra homologation parts needed to turn the Sierra into a touring car bruiser. Bigger turbo, revised aerodynamics, extra engine potential – all the things that make motorsport engineers smile and insurance underwriters stare into the middle distance.
On track, the Sierra Cosworth became a proper menace. In RS500 form especially, it dominated touring car racing around the world, from Britain to Australia. It was fast, spectacular and occasionally controversial, which is exactly what racing saloons should be. A Sierra with a huge wing bullying rivals down the straight remains one of the great 1980s motorsport images.
On the road, the Cosworth became something else again: a legend with a complicated reputation. It was adored by enthusiasts, coveted by joyriders and watched nervously by insurers. The very things that made it brilliant – speed, tuneability, recognisable looks, Ford parts-bin usability – also made it a target. For a while, the “Cossie” felt less like a car and more like a national event involving turbo lag, alarm systems and local newspaper headlines.
That notoriety has only added to its mythology. Today, a good Sierra RS Cosworth is a blue-chip fast Ford, especially if it’s an RS500. Values that once seemed absurd now make a strange kind of sense, because this wasn’t just a hot hatch with delusions of grandeur. It was a homologation special that did exactly what it was built to do.
Forty years on, the Sierra RS Cosworth still has that charge. It’s loud without necessarily making a sound, famous before it even turns a wheel. The wing, once a headache for cautious dealers, became the whole point.
Ford set out to build a racing car for the road. It accidentally built a folk hero.
