The Ford Sierra RS Cosworth was a high-performance version of the Ford Sierra. It was the result of a Ford Motorsport project with the purpose of producing an outright winner for Group A racing in Europe.
The project was defined by Stuart Turner in the spring of 1983. He had recently been appointed head of Ford Motorsport in Europe, and he realised right away that Ford was no longer competitive in this area.
Turner got in touch with Walter Hayes, at the time the vice-president of public relations at Ford, to get support for the project. Hayes had earlier been the driving force behind the development of the Ford GT40 that won Le Mans in 1966, and the Cosworth DFV engine that brought Ford 154 victories and 12 world championships in Formula One during the 1960s and 1970s. Hayes found the project very appealing and promised his full support.
Turner then invited Ken Kohrs, vice-president of development, to visit Ford’s longtime partner, the automotive company Cosworth, where they were presented a project developed on Cosworth’s own initiative, the YAA engine. This was a twin cam, 16-valve engine based on Ford’s own T88 engine block, better known as the Pinto. This prototype proved an almost ideal basis for the engine Turner needed to power his Group A winner.
Therefore, an official request for a turbocharged version (designated Cosworth YBB) capable of 180 HP on the street and 300 HP in race trim, was placed. Cosworth answered positively, but they put up two conditions: the engine would produce not less than 150 kW (204 HP) in the street version, and Ford had to accept no fewer than 15,000 engines. Turner’s project would only need about 5,000 engines, but Ford nevertheless accepted the conditions. The extra 10,000 engines would later become one of the reasons Ford also chose to develop a four door, second generation Sierra RS Cosworth.
To find a suitable gearbox proved more challenging. The Borg-Warner T5, also used in the Ford Mustang, was chosen, but the higher revving nature of the Sierra caused some problems. Eventually Borg-Warner had to set up a dedicated production line for the gearboxes to be used in the Sierra RS Cosworth.
Many of the suspension differences between the standard Sierra and the Cosworth attributed their development to what was learned from racing the turbocharged Jack Roush IMSA Merkur XR4Ti in America and Andy Rouse’s successful campaign of the 1985 British Saloon Car Championship. Much of Ford’s external documentation for customer race preparation indicated “developed for the XR4Ti” when describing parts that were Sierra Cosworth specific. Roush’s suspension and aerodynamics engineering for the IMSA cars was excellent feedback for Ford. Some production parts from the XR4Ti made their way into the Cosworth such as the speedometer with integral boost gauge and the motorsport 909 chassis stiffening plates.
In April 1983, Turner’s team decided on the Sierra as a basis for their project. The Sierra filled the requirements for rear wheel drive and decent aerodynamic drag. A racing version could also help to improve the unfortunate, and somewhat undeserved, reputation that Sierra had earned since the introduction in 1982.
Lothar Pinske, responsible for the car’s bodywork, demanded carte blanche when it came to appearance in order to make the car stable at high speed. Experience had shown that the Sierra hatchback body generated significant aerodynamic lift even at relatively moderate speed.
After extensive wind tunnel testing and test runs at the Nardò circuit in Italy, a prototype was presented to the project management. This was based on an XR4i body with provisional body modifications in fibreglass and aluminium. The car’s appearance raised little enthusiasm. The large rear wing caused particular reluctance. Pinske insisted however that the modifications were necessary to make the project successful. The rear wing was essential to retain ground contact at 300 km/h, the opening between the headlights was needed to feed air to the intercooler and the wheel arch extensions had to be there to house wheels 10” wide on the racing version. Eventually, the Ford designers agreed to try to make a production version based on the prototype.
Superkart is a form of motor racing in which the class is a racing vehicle sized like a kart but with several characteristics more strongly associated with open-wheel racing cars.
The most obvious difference between a Superkart and any other form of kart is that they have full aerodynamic bodykits and can race on car circuits over 1,500 metres in length. The power unit, most often, but not exclusively two stroke 250 cc engines, can be specially designed kart engines or production motorcycle engines with either five or six-speed sequential gearboxes. Owing to their high top speed and superb cornering ability, a Superkart’s aerodynamic bodywork includes a front fairing, larger sidepods, and a rear wing. They use either 5-or-6-inch-diameter (130 or 150 mm) tires and wheels and most often race on full size auto-racing circuits.
250 cc Superkarts often[quantify] set faster lap times than much more expensive and technically advanced racing machines. Some British and Australian classes also include 125 cc gearbox karts.
Superkarts race on “long circuits” (e.g. Silverstone, Laguna Seca, Magny-Cours). In the UK they also race on “short circuits” (e.g. Kimbolton), “short circuits” are under 1,500 metres in length.
Superkarts are raced worldwide. There is a multi-event CIK-FIA European Superkart Championship (for 250 cc karts only), and there has in the past been a World Championship, which was last run in 1995.
Powered by a 2-stroke 250 cc engine producing 62 hp for an overall weight including the driver of 205 kilograms, Superkarts have a power/weight ratio of 440 hp/tonne (330 W/kg)(c.5 lbs/hp). Superkarts can accelerate from 0 to 60 mph in less than 3 seconds with a top speed of 155 mph (250 km/h). Their low weight and good downforce make for excellent cornering and braking abilities. A Superkart is capable of braking from 100 mph (160 km/h) to standstill in around 2 seconds, and taking corners at nearly 3 g (30 m/s²).
At some circuits, Superkarts are the outright lap-record holders, at others they run at around Formula 3 lap times.
Ben Wilshire British 125 Open class Superkart
British Superkart Divisions :
Main article: British Superkart Championship
Division 1 is open to 250 cc karts with one or two cylinders and five or six speed gearboxes. Typically the karts produce 100 hp and are capable of 160 mph – the fastest form of kart. This formula was previously known as Formula E.
Division 2 is for single cylinder karts with 5 and 6-speed boxes. Typically these karts produce 65 hp and are capable of 140 mph. However, being lighter than the twin cylinder (Division 1) karts they can be as quick on twisted circuits. This formula was previously known as 250 International. However the main British series is for single cylinder 250 cc karts with 5-speed only, also known as 250 National.
125 Open – Powered by 125 cc engines and again featuring 6-speed sequential gearboxes, this sprint kart class uses lighter chassis than the 250’s.
125 ICC (KZ) – Powered by similar 6-speed 125 cc engines to the 125 Open class with tighter tuning restrictions, this CIK sprint kart class hosts some of the closest Superkart racing in the UK.
2007 Australian 250 cc International champion Warren McIlveen (Stockman-Honda)
Australian Superkart Classes:
Main article: Australian Superkart Championship
Superkarting in Australia has, since 1989, referred to any form of racing kart to race on full-size motor racing circuits, usually as sanctioned by the Australian ASN, CAMS.
250 cc International – commonly referred to as twins or inters, these karts are powered by twin cylinder engines and usually have 6-speed sequential gearboxes. Several European and North American chassis are popular in addition to locally developed designs.
250 cc National – single cylinder class, the 250 National class is powered by 250 cc motocross engines and also feature 6-speed sequential gearboxes.
125 cc Gearbox – most often powered by 125 cc Honda and Yamaha Grand Prix motorcycle engines equipped with six speed sequential gearboxes, this Superkart class uses mostly the same chassis as the 250 classes. They run at lighter weights than the 250 classes, which makes for close racing with mid-field 250 Nationals at some circuits. Video Rating: / 5