1986 Ford Sierra RS Cosworth
Together, Ford and Cosworth released the Sierra Cosworth RS as a homologation special for Group A rally. Thankfully 5000 examples were needed for homologation into Group A rally and by 1986 the car went into regular production.
The Cosworth-developed YBB engine was a Pinto-based block with a Cosworth aluminum head. It was equipped with an intercooled Garret AirResearch TO3 turbocharger that delivered 9psi of boost, resulting in just over 200 horsepower. While for a road car this power was exceptional, especially given the price, in motor sport it was not ample. Given the fact that the car was also rear-wheel-drive and suffered from turbo lag, it is no surprise it didn’t take any outstanding victories in Group A.
Although unsuccessful in rally, the RS Cosworth was quite capable on the road. It even out-powered and weighed less than the BMW’s E30 M3. As a result the car achieved a top speed of 150 mph with a sub six second run to sixty mph.
Based in the RS Cosworth, 500 special RS500 models were built with a more powerful engine. Eventually the whole project evolved into the Escort Cosworth RS which was a more purpose built machine.
In Detail
| submitted by | Richard Owen |
| engine | Cosworth-developed, Cast Iron, YBB Pinto-Based Inline-4 |
| position | Front Longitudinal |
| aspiration | Garrett AiResearch TO3 Turbocharger |
| valvetrain | Belt Driven DOHC, 4 Valves per Cyl |
| fuel feed | Weber-Marelli Microprocessor-Managed Fuel Injection |
| displacement | 1993 cc / 121.6 in³ |
| bore | 91 mm / 3.58 in |
| stroke | 77 mm / 3.03 in |
| power | 149.9 kw / 201 bhp @ 6000 rpm |
| specific output | 100.85 bhp per litre |
| bhp/weight | 161.19 bhp per tonne |
| torque | 276.59 nm / 204 ft lbs @ 4500 rpm |
| driven wheels | RWD w/LSD |
| front tires | Dunlop D40 205/50 VR 15 |
| rear tires | Dunlop D40 205/50 VR 15 |
| front brakes | Vented Discs w/4-Piston Calipers |
| f brake size | x 283 mm / x 11.14 in |
| rear brakes | Solid Discs |
| r brake size | x 273 mm / x 10.75 in |
| front wheels | F 38.1 x 17.8 cm / 15 x 7 in |
| rear wheels | R 38.1 x 17.8 cm / 15 x 7 in |
| steering | Rack & Pinion w/Power Assist |
| f suspension | MacPherson Struts w/Lower Control Arms, Coil Springs, Anti-Roll Bar |
| r suspension | Semi-Trailing Arms w/Coil Springs, Anti-Roll Bar |
| curb weight | 1247 kg / 2750 lbs |
| wheelbase | 2609 mm / 102.7 in |
| front track | 1443 mm / 56.8 in |
| rear track | 1461 mm / 57.5 in |
| length | 4493 mm / 176.9 in |
| width | 1699 mm / 66.9 in |
| height | 1377 mm / 54.2 in |
| transmission | Borg Warner T5 5-Speed Manual |
| gear ratios | :1 |
| top speed | ~241.4 kph / 150 mph |
| 0 – 60 mph | ~6.0 seconds |
| 0 – 100 mph | ~16.0 seconds |
