The Ford Sierra RS Cosworth 4×4 arrived around 1990 as the next major evolution of the Cosworth-powered Sierra. Building on the success of the earlier rear-wheel-drive cars, it introduced four-wheel drive to improve traction and stability while retaining the turbocharged performance and strong motorsport connection that had already made the Cosworth name legendary.

By 1991, the Sierra 4×4 Cosworth represented one of the final developments of the model before Ford shifted its performance focus to the Escort RS Cosworth.

Under the bonnet sits a turbocharged 2.0-litre DOHC inline-four from the Cosworth YB family. In this catalyst-equipped specification, it produces 215 PS and 290 Nm of torque.

Power is sent through a five-speed manual gearbox to all four wheels. The four-wheel-drive system is rear-biased, preserving much of the character of the earlier Sierra Cosworth while providing substantially improved traction under acceleration and on low-grip surfaces.

Performance remains impressive even by later standards. The Sierra RS Cosworth 4×4 accelerates from 0–100 km/h in around 6.5 seconds and is capable of more than 230 km/h.

The turbocharged engine delivers the distinctive old-school Cosworth character: relatively restrained at lower revs, followed by a much stronger surge of performance as boost builds.

The chassis was extensively developed to handle the additional performance and four-wheel-drive system. Independent suspension, firmer springs, model-specific dampers and upgraded brakes give the car considerably greater stability than a conventional Sierra.

Compared with the earlier rear-wheel-drive Cosworth, the 4×4 is more composed when accelerating out of corners and significantly more capable in difficult conditions. It nevertheless retains an engaging, mechanically direct character.

Visually, the four-door Sierra Cosworth is far more discreet than the famous three-door model with its enormous rear wing. The saloon body gives it an almost understated appearance, while distinctive spoilers, bumpers and wheels hint at the performance underneath.

Inside, the formula remains simple and driver-focused, with RECARO sports seats, traditional analogue instruments and very little separating the driver from the mechanical workings of the car.

The 1991 Ford Sierra RS Cosworth 4×4 represents one of the final chapters of the Sierra Cosworth story. It combines the legendary turbocharged Cosworth engine with a rear-biased four-wheel-drive system and the relatively understated body of a practical four-door saloon.

Today, it is an increasingly desirable modern classic and a reminder of an era when road-going performance cars retained an unusually direct connection to Ford’s motorsport programme.