Kart racing

General info:

Kart racing or karting is a variant of open-wheel motorsport with small, open, four-wheeled vehicles called karts, go-karts, or gearbox/shifter karts depending on the design. They are usually raced on scaled-down circuits. Karting is commonly perceived as the stepping stone to the higher and more expensive ranks of motorsports.
Karts vary widely in speed and some (known as Superkarts) can reach speeds exceeding 160 miles per hour (260 km/h), while go-karts intended for the general public in amusement parks may be limited to speeds of no more than 15 miles per hour (24 km/h). A KF1 kart, with a 125 cc 2-stroke engine and an overall weight including the driver of 150 kilograms has a top speed of 85 miles per hour (137 km/h). It takes a little more than 3 seconds to go from 0 to 60 mph with a 125 cc shifter kart (6 gears), with a top speed of 115 miles per hour (185 km/h) on long circuits.

History of Karting:

Art Ingels is generally accepted to be the father of karting. A veteran hot rodder and a race car builder at Kurtis Kraft, he built the first kart in Southern California in 1956. Karting has rapidly spread to other countries, and currently has a large following in Europe.
The first kart manufacturer was an American company, Go Kart Manufacturing Co. (1958). McCulloch was the first company, in 1959, to produce engines for karts. Its first engine, the McCulloch MC-10, was an adapted chainsaw 2-stroke engine. Later, in the 1960s, motorcycle engines were also adapted for kart use, before dedicated manufacturers, especially in Italy (IAME), started to build engines for the sport.

 Engine:

Amusement park go-karts can be powered by 4-stroke engines or electric motors, while racing karts use small 2-stroke or 4-stroke engines.

• 4-stroke engines can be standard air-cooled industrial based engines, sometimes with small modifications, developing from about 5 to 20 hp. Briggs & Stratton, Tecumseh, Kohler, Robin, and Honda are manufacturers of such engines. They are adequate for racing and fun kart applications. There are also more powerful four-stroke engines available from manufacturers like Yamaha, TKM, Swissauto or Aixro (Wankel engine) offering from 15 hp up to 48 hp. They run to and around 11,000 rpm, and are manufactured specifically for karting. Those are used in some National Championship classes like the two-strokes.

• 2-stroke kart engines are developed and built by dedicated manufacturers. WTP, Comer, IAME (Parilla, Komet), TM, Vortex, Titan, REFO, TKM, PRD, Yamaha and Rotax are manufacturers of such engines. These can develop from about 8 hp for a single-cylinder 60 cc unit (MiniROK by Vortex) to 90 hp for a twin 250 cc. Today, the most popular categories worldwide are those using the Touch-and-go (TAG) 125 cc units. The recent 125 cc KF1 engines are electronically limited at 16,000 rpm. Most are water-cooled today; however, previously air-cooled engines dominated the sport.

Racing Formats

Sprint

Sprint racing takes place on dedicated kart circuits resembling small road courses, with left and right turns. Tracks range from 1/4 mile (400 metres) to over 1 mile (1,600 metres) in length.
The sprint format is a series of short-duration races, normally for a small number of laps, that qualify for a final, with a variety of point scoring calculations to determine the event's overall winner. Typical duration does not normally exceed 15 minutes. Here, speed and successful passing is of the most importance. It normally occurs in the format of three qualifying heats and a final race for trophy positions.
The FIA championships, including the Karting World Championship, take place in this format.

Endurance

Endurance races last for an extended period, from 30 minutes up to 24 hours or more, for one or more drivers. In general, consistency, reliability, and pit strategy is of greater importance than all out speed.

Called "Enduro" racing in the USA, most WKA & IKF sanctioned events typically last 30 minutes (Sprint Enduro) or 45 minutes (Laydown Enduro) and are run continuous without pit stops. Enduro events are held on full-size road racing circuits that are usually between 1.5 & 4 miles in length.
As well as the famous 24 Hours of Le Mans race for automobiles there is also a 24 hours event for karts which takes place at the kart circuit Alain Prost at Le Mans, France. This race has taken place since 1986 and its winners list include four times Champ Car champion Sébastien Bourdais (in 1996).

Speedway

Speedway racing takes place on asphalt or clay oval tracks which are normally between 1/6 mile and 1/4 mile long. Tracks primarily consist of two straights and four left-turn corners, few tracks are symmetric and often the shape parallels that of an egg or a tri-oval.

'Offset' kart chassis have been developed for precise handling and adjustability in left-turn-only racing competition taking place on oval and tri-oval tracks.
Speedway kart races range in length from 4 laps for a trophy dash, to 20 laps for a main event.
The two chief racing formats used in dirt speedway karting are heat races and timed laps qualification:

• The International Kart Federation (IKF) runs a racing format of two 10 lap heats followed by a 20 lap final. Finishing positions in the two heat races are used to calculate the starting position in the feature race.
• The World Karting Association (WKA) uses time qualifying. Karts equipped with transponders are sent out onto the track in groups of 5 or less to try to achieve the fastest lap time. Positions for the 20 laps feature event are determined by qualifying time.
• The American Kart Racing Association (AKRA) uses group transponder qualifying to calculate starting positions for 20-lap features.