Sierra Cosworth Introduction The Sierra RS Cosworth was introduced in 1986 but had been in development since 1981. The looks of the Cosworth were very different to other Sierras with an RS body-kit, large rear spoiler & changes to the front grill & bumper. This RS was very successful in motorsport, both rally and track. The engine was based on the "Pinto" block with the Cosworth developed 16 valve aluminum head. The 16v head was originally going to be a tuning part offered by Cosworth for the humble OHC engine.

Sierra Cosworth Specifications Engine: Cosworth YBT 16-valve, 1993cc, Bore 90.92, Stroke 76.95mm, compression ratio 8:1. Garrett T03 water-cooled turbocharger. Max power 204hp at 6000rpm, max torque 278Nm at 4500rpm. Fuel System: Weber-Marelli engine management system. Transmission: 5-speed Borg-Warner T5 gearbox, 240mm single plate clutch, 3.65:1 final drive. Suspension Front - McPherson struts, 28mm anti-roll bar. Rear - semi-trailing arms, coil springs, 14mm anti-roll bar. Brakes: Front - 283mm vented discs, four-pot calibers. Rear - 273mm solid discs.