Few cars scream ’80s performance icon quite like the Ford Sierra Cosworth and even fewer are as instantly recognisable or as unapologetically rowdy as the wide-arched, whale-tailed icon. For today’s Behind The Wheel contributor, Simon, this car wasn’t just a poster on the bedroom wall. It was a dream he chased, caught, and built into something genuinely special.
Back in the day, Simon was already living the Cosworth life with a white Sapphire Cosworth as his daily driver, but the temptation of the original Sierra Cosworth was always there and we don’t blame him!
The Sierra Cosworth is a holy grail car for any Ford enthusiast. With its opinion splitting whale tail spoiler and that iconic Cosworth YB engine, the car was a cult classic. Designed and built to win races, the Sierra Cosworth proved to be an instant success, by June of 1987 (the first year that it competed on track) it had already won the first two rounds of the Monroe British Championship, the Willhire 24 Hour race at Snetterton and the Nurburgring 24 hours. This was all made possible in part thanks to that legendary Cosworth YB engine, which initially gave the Sierra Cosworth a whopping 204bhp on the road and approximately 375bhp in the first competition cars (which would only increase as time went on), the later homologation special Cosworth RS500 would go on to produce an even greater 224bhp in the road car and an ‘easy’ 486bhp in racing form.
Fast forward from the 1980’s to the 2000’s when in 2008 a Sierra Cosworth came up for sale in Portsmouth albeit imperfect and missing a few bits but nonetheless exactly what Simon had been long wanting, he made a snap decision to sacrifice the Sapphire Cosworth and repurpose its freshly rebuilt engine so that the Sierra project could begin. What followed was a 14 hour long round trip involving a trailer, his brother and his mate, all part of the journey that brought the Sierra home ready to kickstart its transformation. The result today is a highly personalised Cosworth that still wears its 1986 roots proudly, but with a modernised edge and some serious hardware under the bonnet.
Power now sits at a hefty 403 bhp, with a spec list that reads like a greatest hits of ’90s and early 2000s tuning culture. The car features a T34 hybrid turbo, 4×4 cylinder head and cams, Siemens 55 injectors, Swedish-style polished plenum, and a Group A K&N filter, all supported by an L8 ECU with a live map from Motorsport Developments (there’s no point in doing anything half-heartedly!). With anti-lag, launch control, and a Helix 6-paddle clutch, the car delivers plenty of thrills. However, Simon does admit that the clutch can be tiring after a while and so hydraulic clutch conversion might be on the cards to make the overall driving experience a bit more comfortable! Not that the Cosworth could get any better looking, but Simon has just refurbished a set of old school TSW Hockenheim alloys to really set the car off.
Inside, everything remains largely original, except for a cluster of aftermarket pillar-mounted gauges monitoring boost, oil pressure, water temp, AFR, and volts. There are no digital screens, no modern infotainment, the Sierra Cosworth is just a raw, analogue driving experience, but that’s precisely the appeal. Since Simon bought the car, it’s been to shows like Fast Ford and other enthusiast meets. In recent years it’s had more garage time than road time with Simon working at a football stadium and often working weekends. However, that’s beginning to change with 2025 so far shaping up to be the year that the Cosworth comes out of hibernation.
Out on the road, the Cosworth never fails to draw attention. It’s not just the boost or the turbo chatter, it’s the presence. People stop, stare, and smile. There’s a shared level of nostalgia amongst petrolheads towards the Sierra Cosworth and Simon’s example makes an impression wherever it goes. It’s not a daily, it’s not for comfort and it’s certainly not for the faint-hearted. It’s the kind of car that requires commitment, rewards attention and still threatens to go sideways at the twitch of a throttle. For Simon and so many other Ford fanatics, that’s exactly why the Sierra Cosworth will always be THE dream car.
We’d say keep your eye out for Simon’s Sierra Cosworth at our future meets, but let’s be honest you’ll spot it regardless… just look for the crowd of people drooling over a car!
Car Facts:
Make: Ford
Model: Sierra Cosworth (3DR)
Year: 1986
Engine: 1993cc
BHP: 403bhp
Top Speed: 150mph… maybe 160 with a good gust of wind
0-62: Around 5.5 sec if I lose some weight (Simon’s words!)
Weight: Standard plus all the wax and polish
Additional modifications: 4×4 cylinder head and cams, T34 hybrid turbo, Siemens 55 injectors, Swedish style polished plenum, Samco hoses, iridium plugs, group A K&N filter, 205 block with pocketed pistons and arp bolts, high pressure oil pump, Helix 6 paddle clutch, Grp A dump valve with kevlar diaphragm, magnecore plug leads, Magnet stainless steel exhaust, polished Bailey oil breather system, polished header tank power steering tank, turbo cooler, alloy radiator and rs500 intercooler, one off stainless turbo heat shield, polished strut brace, antilag & launch control, L8 ECU Motorsport developments live map
Wheels – front 8”x18” 215/35/18. rears 9”x 18” 225/35/18
Body – original RS500 front bumper & splitter, original RS500 upper and lower spoilers
