Noble Sisters: Ford Cosworth, Sierra & Escort

Cosworth is a name that has made history in motorsport, renowned for its successes in Formula 1 and for creating sporty road cars that have become highly coveted collector's items today. Founded in 1958 by Mike Costin and Keith Duckworth—whose surnames combine to form Cosworth—both were former Lotus employees. Funded by Ford, Costin and Duckworth designed the engine that marked Formula 1 history: compact, lightweight, fuel-efficient (important for reducing vehicle weight), and reliable, it became the iconic engine for British teams.

With 176 wins in Formula 1, Cosworth is the third most successful engine manufacturer in F1 history, behind only Ferrari and Mercedes. The Cosworth brand became synonymous with high performance, and its partnership with Ford naturally led to the creation of road models that carried a "whiff of Formula 1".

The Ford Sierra RS represents one of the most successful chapters of the Ford and Cosworth collaboration. It was unveiled at the 1985 Geneva Motor Show and launched in 1986.

The Sierra RS Cosworth was one of the most glorious achievements of the Ford-Cosworth collaboration. Designed to compete in Group A of the Rally and Touring Car Championships, the Sierra RS was developed under Stuart Turner, then head of Ford Motorsport Europe. Debuting at the 1985 Geneva Motor Show, the car featured the Cosworth YBD engine, a 2-liter turbocharged four-cylinder with Weber-Marelli injection, delivering 204 hp. Its standout feature became the large shelf-like rear wing, installed to enhance downforce and improve road grip.

A distinctive feature of the Sierra RS Cosworth is its large shelf-like rear wing, designed to improve road grip.

In 1987, the Sierra RS, under the 500 Cosworth designation, introduced a more powerful version for track competitions. With an upgraded turbocharger, a larger intercooler, and other tweaks, the engine produced 227 hp. Only 500 RS500 models were built by Aston Martin Tickford, becoming a legend in touring car racing with numerous wins in various championships.

Just a year after its market launch, the Sierra RS500 Cosworth became legendary with numerous wins in various touring car championships.

The Sierra RS Cosworth's success prompted Ford to release a four-door version, dubbed the Sapphire, which was initially rear-wheel drive and later offered with all-wheel drive. The latter, launched in 1990, featured the YBG engine with 220 hp, offering greater stability and superior performance. By 1992, the Sierra RS Cosworth was retired to make way for the new Escort RS project.

The Sierra RS Cosworth was also offered in a four-door version, initially rear-wheel drive and later with all-wheel drive, before retiring in 1992 for the Escort RS Cosworth.

The Ford Escort RS Cosworth was designed to compete in the World Rally Championship. Debuting in 1992 as the successor to the Sierra RS Cosworth, it inherited the chassis while featuring the Cosworth YBT engine, a 2-liter turbo delivering 224 hp. Expectations were high, but between 1993 and 1996, the car achieved only eight overall wins, falling short of claiming a WRC title. Despite this, it became one of the most iconic rally cars ever, generating significant profits for Ford.

The Ford Escort RS Cosworth carried on the Sierra’s legacy, retaining the large rear wing and proving to be an excellent rally car.

Like the Sierra, the Escort RS Cosworth was also renowned for its large rear wing, designed to maximize downforce, and its brutal Garrett T34 turbocharger, which gave it a "wild" character. For less "wild" customers, a smaller Garrett T25 turbocharger was introduced in 1994, improving everyday drivability without sacrificing too much performance. Today, the Escort RS Cosworth is valued at €60,000–€80,000, while the Sierra RS Cosworth fetches even higher, with average prices of €80,000–€100,000.

Today, the Ford Escort RS Cosworth is one of the most desired youngtimers, with values ranging from €60,000 to €80,000.