Sierra Cosworth RS500
The Ford Sierra RS Cosworth was launched in the summer of 1986, around June. It became the first road car to be listed with an output greater than 100 bhp per litre. It came about because the Motorsport division of Ford wanted a saloon racer and rally car to use in international motorsport. Thus the concept of the Cosworth was concieved.
In order for the Cosworth to be eligible for international motorsport it needed to be homologated. International Group A homologation required 5000 road going versions of the car to be produced in a 12 month period. So Ford commisioned Cosworth to build the 5000 engines needed, while Ford Special Vehicle Engineering, with help from the Motorsport division, designed the car. So the Sierra Cosworth was born!!
Cosworth devolped its YB engine prototype into an engine worthy of the Cosworth name. Ford asked for a 2 litre engine with around 180 bhp with scope for 300 bhp. They got their 2 litres but the power outputs were very different. With over 210 bhp as standard with scope for near 400bhp, the engine exceeded all expectations. With a super efficient 16 valve cylinder head, a turbo charger and electronic fuel injection, the engine was easily one of the best in a road going production car.
The sucess of the Sierra as a racer and rally car depended on its road holding abilities. So an aerodynamic package had to be developed for the car. This develoment resulted mostly in the huge rear wing. Ford executives freaked out at the idea of one its saloon cars with a huge rear wing but the Motorsport division said it was essential so it stayed.
So that's a brief and by no means complete account of how the Cosworth came about. So onto the RS500. Even before the Cosworth hit the road the Motorsport team were developing the evolution version. The rules of motorsport state that further developments of an already homologated car must be supported by a further 500 cars. It was built to make doubly sure that the Sierra would dominate racing and rallying championships around the world. So Cosworth further developed the YBB block used in the normal Cosworth (more about the engines later) and came up with the YBD. The engine was capable of producing more than 600 bhp (the YBB could only produce 380-400 bhp in race trim) and 900+ bhp has also been achieved. With 8 injectors, larger turbo, modified head, strengthened block and tweaked engine management. Discrete body modifications over the standard Cosworth were also added. Coupled with suspension modifications the RS500 was born. RS500 Specification Engine: 1993cc, 16v, 4-cylinder, DOHC, twin-cam, Cosworth YBD engine. Water-cooled Garrett AiResearch T04 turbocharger, Weber-Marrelli fuel injection and engine management. 90.82mm bore, 76.95mm stroke. 525 engines made for the RS500 were numbered: YBD 0015-0537
Interior: Only one trim specification was available: Recaro seats, factory sunroof, etc.
Tranmission: Borg-Warner T5 five-speed manual gearbox. Front engined, rear wheel drive. Ratios: 1st, 2.95:1; 2nd, 1.95:1; 3rd, 1.34:1; 4th, 1.1:1; 5th, 0.80:1; Reverse, 2.75:1; Final drive, 3.64:1.
Suspension Front: Independant coil springs, gas shocks, MacPherson struts.
Rear: Different from the standard Cosworth with elongated rear beam to allow longer wheel base for racing.
Ride height is 10mm higher than the standard Sierra.
Wheels & Tyres 7x15 cross latice alloys all round. Dunlop D40 tyres (no longer produced). On both standard Sierra Cosworth and RS500 you can fit 17inch wheels without modifications to the body.
Brakes Front: 283mm vented discs
Rear: 273mm solid discs
Electronic ABS as standard. Standard replacement discs cost £150.
Body 500 body shells were produced by Tickford during June and July 1987. Visually different from the standard Sierra RS Cosworth, the RS500 had a different front bumper with more, larger air intakes, extra rubber wing taken from the Sierra 2.0iS on the bootlid and an extra 30mm lip on the huge rear wing. Bodykit is no longer made.
Performance Maximum power: 224 bhp @ 6000 rpm
Maximum torque: 206 lb/ft @ 4500 rpm
0-60 mph: around 6.2 seconds
Maximum speed: about 150 mph
Specific power output: 112.39 bhp/litre
With over 500 bhp produced from RS500 engines (the record is over 900 bhp and can be found in a grass track racer!!) the RS500 was the complete racer. Graham Goode Racing were approached to race their RS500 in Malaysia in 1991. The car was shipped to Malaysia and was sponsored by Petronas, the national oil company of Malaysia. The car ran in four races per year, each one a double race and finished first in all but one race where the car could only manage second. You may think that the cars it raced against were poor. Think again!! The cars included: AMG Mercedes Evo 2, German Touring Car Alfa Romeo V6, AC Schnitzer 2.5l M3 Evo and also one of the all conquering Nissan Skyline GTR's from the Australian Touring Car Championship. This proves the RS500's worth as a racer. GGR further devolped the RS500 and produced a car with 6-speed geabox, uprated LSD etc to race in the 1994 season. It's qualifying form was so good the other competitors lobbied to have the rules changed to make the car illegal in the series. GGR promptly entered the car in non-championship events and won every race. The RS500 was truly a racer beyond all expectations and will continue to astound fans in rallies and special series' for years to come