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Artist rendering of a NASCAR restrictor plate

A Restrictor plate or air restrictor is a device installed at the intake of an engine to limit its power. This kind of system is occasionally used in road vehicles (e.g., motorcycles) for insurance purposes, but mainly in automobile racing, to limit top speed and thus increase safety, to provide equal level of competition, and to lower costs. Image File history File links File links The following pages link to this file: Restrictor plates ... Image File history File links File links The following pages link to this file: Restrictor plates ... Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ...

Racing series

A few top classes like Formula One limit only the displacement and air intake mouth dimension. However, in 2006 air restrictors (as well as rev limiters) were used by Scuderia Toro Rosso to facilitate the transition to a new engine formula. F1 redirects here. ... Scuderia Toro Rosso (Italian for Red Bull Stable) is a Formula One racing team owned in a 50/50 partnership between the drinks company Red Bull and former F1 driver Gerhard Berger, and which made its racing debut in the 2006 Formula One season. ...

Many other racing series use additional air restrictors (or limit boost pressure in turbo engines).

• Formula 3, 2000cc, 215 hp
• Deutsche Tourenwagen Masters, 4000cc, 470 hp
• Automobile Club l'Ouest sports car racing, 400 to 600 hp in various classes
• American Le Mans Series sports car racing, 400 to 600 hp in various classes

Formula Three is a class of auto racing. ... The Deutsche Tourenwagen Masters (DTM, German Touring Car Masters) is a touring car racing series based in Germany, but also with rounds elsewhere in Europe. ... IMSA GTP sports cars racing at Mid-Ohio Sports Car Course in 1991 Sports car racing is a form of circuit auto racing with automobiles that have two seats and enclosed wheels. ... The American Le Mans Series (ALMS) is a series of automobile races. ... IMSA GTP sports cars racing at Mid-Ohio Sports Car Course in 1991 Sports car racing is a form of circuit auto racing with automobiles that have two seats and enclosed wheels. ...

Rallying

After Group B cars were outlawed from rallying because they were too powerful (rumored to have reached 600 hp), too fast and too dangerous, the FISA decided that rally cars should not have more than 300 hp. For a while no special restrictions were needed for that (e.g. the Group A Lancia Delta HF 4WD had about 250 hp in 1987). But with development in the 1990s, Group A cars were rumored to have reached 400 hp or more. So the FIA mandated restrictors for supercharged and turbocharged engines in all categories (World Rally Car, Group A and Group N). Group B Ford RS200 The Group B referred to a set of regulations for competition vehicles in sportscar racing and rally racing regulated by the FIA. Group B was introduced by the FIA in 1982 as replacement for both Group 4 (modified grand touring) and Group 5 (touring prototypes) cars. ... The Fédération Internationale de lAutomobile, commonly referred to as the FIA, is a non-profit association established in 1904 to represent the interest of motoring organisations and motor car users. ... hp redirects here. ... In relation to motorsport governed by the FIA, Group A referred to a set of regulations providing production-derived vehicles for outright competition. ... The Lancia Delta is a small family car produced by Italian automaker Lancia from 1979 to 1994. ... In relation to motorsport governed by the FIA, Group A referred to a set of regulations providing production-derived vehicles for outright competition. ... The Fédération Internationale de lAutomobile, commonly referred to as the FIA, is a non-profit association established on June 20, 1904 to represent the interest of motoring organisations and motor car users. ... For other meanings, see supercharger (disambiguation) A supercharger (sometimes called a blower), a positive displacement or centrifugal pump, is a gas compressor used to pump air into the cylinders of an internal combustion engine. ... Turbocharger Cut-away A turbocharger is a device used in internal-combustion engines to increase the power output of the engine by increasing the mass of oxygen and fuel entering the engine. ... Subaru Impreza WRC Toyota Corolla WRC Škoda Fabia WRC World Rally Car is a term used to describe the racing automobiles built to the specification set by the FIA and used to compete in the outright class of the World Rally Championship (WRC). ... In relation to motorsport governed by the FIA, Group A referred to a set of regulations providing production-derived vehicles for outright competition. ... In relation to motorsport governed by the FIA, Group N referred to a set of regulations providing a set of rules for standard production vehicles for competition, often referred to as the Showroom Class. This contrasts with the Group A all-out competition production-derived vehicles. ...

This means that the rally version of a car like the Mitsubishi Lancer Evolution can have less power than the street version (the "280" hp Evo VII was believed to have more than 300 hp, and in some markets the FQ-320, FQ-340, FQ-360, FQ-400 versions were sold, with the number representing the total horsepower). The Mitsubishi Lancer Evolution, colloquially known as the Evo, is a car manufactured by Mitsubishi Motors. ...

It also means that the torque and power curves of the engine are unusual. The engine produces peak torque and almost maximum power at a relatively low RPM, and from there to the rev limiter the torque drops and the power does not increase much. For other senses of this word, see torque (disambiguation). ... In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time. ... A Rev limiter is a device fitted to a petrol internal combustion engine to restrict its maximum rotational speed. ...

In 1995 Team Toyota Europe used an illegal device to bypass the restrictor (allowing an estimated extra 50 hp). Due to this the team lost their results in the 1995 season and was banned from rallying until the end of 1996. Team Toyota Europe is a Toyota division based in Köln, Germany. ...

NASCAR

NASCAR's Sprint Cup and Nationwide Series currently uses restrictor plates at Daytona International Speedway and Talladega Superspeedway. NASCAR routinely states that the Sprint Cup restrictor plate reduces engine power from approximately 750 hp to approximately 430 hp. Jeff Burton (99), Elliott Sadler (38), Ricky Rudd (21), Dale Jarrett (88), Sterling Marlin (40), Jimmie Johnson (48), and Casey Mears (41) practice for the 2004 Daytona 500 The National Association for Stock Car Auto Racing (NASCAR) is the largest sanctioning body of motorsports in the United States. ... The Sprint Cup is a Group 1 United Kingdom flat racing horse race for those horses aged three years and above run over a distance of 6 furlongs at Haydock Park during September. ... The NASCAR Busch Series is a stock car racing series owned and operated by NASCAR. It is NASCARs minor league circuit (often compared to Triple-A baseball), and is a proving ground for drivers who wish to step up to the organizations big league circuit, the Nextel Cup. ... Daytona International Speedway is a superspeedway in Daytona Beach, Florida. ... Talladega Superspeedway is a motorsports complex located in Talladega, Alabama. ...

The device limits the power output of the motor, hence slowing both the acceleration and the overall top speed obtainable on the tracks where the cars are so equipped. An undesired effect, however, is that all drivers tend to form very large "packs" of cars that run closely (there may only be one second separating the entire field at times) together for the majority of the race. These large packs reduce air resistance which allows the cars to run faster and makes drafting easier. These restrictions are supposedly in the interest of driver and fan safety, although many members of both of these groups feel that the closeness of cars and their inability to achieve separation may actually make the racing at these tracks more dangerous, as there are often massive and frightening multi-car pileups during races. Such a crash is dubbed "The Big One" by drivers and fans. At Daytona and Talladega, most races are marred by at least one occurrence of such a crash as cars rarely become separated. Talladega is considered the more likely track for these instances to occur as the track is wide enough to have three to four distinct lines of racing, compounding the chances of a mistake by a driver. This article is about the racing technique. ...

Reason for restrictor plates

There have been three reasons that NASCAR used restrictor plates in its history. Jeff Burton (99), Elliott Sadler (38), Ricky Rudd (21), Dale Jarrett (88), Sterling Marlin (40), Jimmie Johnson (48), and Casey Mears (41) practice for the 2004 Daytona 500 The National Association for Stock Car Auto Racing (NASCAR) is the largest sanctioning body of motorsports in the United States. ...

The first use came in 1971 as part of NASCAR's plans to reduce the size of engines from 427 cubic inches (7.0 L) to 358 cubic inches (5.8 L). In order to allow teams with smaller budgets to race the larger engines, NASCAR made mandatory the use of a restrictor plate to be placed on larger engines to equalize performance with smaller engines. The transition ended in 1974, when NASCAR banned the larger engines, and went to the 358 cubic inch engine (a compression limit would be implemented in 1996). This was a transitional process and, as not every car used restrictor plates, this is not what most fans call "restrictor plate racing."

The second use came following the terrifying crash of Bobby Allison at the 1987 Winston 500 at Talladega Superspeedway. Allison's Buick LeSabre blew a tire going into the tri-oval and flew tail-first into catch fencing early in the event, injuring spectators (although not actually entering into the grandstands). After a summer where the two subsequent superspeedway races were run with aids to prevent cars from flying, and smaller carburetors (390 cubic feet per minute instead of 750 cubic feet per minute) proved to be inadequate to sufficiently slow the cars, NASCAR imposed restrictor plates again, this time at the two fastest circuits, both superspeedways: Daytona for all NASCAR-sanctioned races and Talladega for Cup races. The Automobile Racing Club of America also enforced restrictor plates at their events at the two tracks. In 1992, when the Busch Series began racing at Talladega, the plates were implemented. Bobby Allison (born December 3, 1937) was one of the first NASCAR drivers and was named one of NASCARs 50 greatest drivers. ... The Aarons 499 is a NASCAR Nextel Cup stock car race held at Talladega Superspeedway in Talladega, Alabama. ... Talladega Superspeedway is a motorsports complex located in Talladega, Alabama. ... The Buick LeSabre was a full-size car made by the Buick division of General Motors from 1959-2005. ... The carburetor (or carburettor, carb for short) is a device which mixes air and fuel for an internal_combustion engine. ... In North American motorsports, a superspeedway is a race track over one mile (1. ... Daytona International Speedway is a superspeedway in Daytona Beach, Florida. ... Talladega Superspeedway is a motorsports complex located in Talladega, Alabama. ... ARCA Remax Series logo For other uses of ARCA, see ARCA. Michael Simkos ARCA car at Salem Speedway, Indiana The Automobile Racing Club of America (ARCA) is an auto racing sanctioning body in the United States founded in 1953 by John Marcum. ...

In some tracks, NASCAR's concerns with speeds because of power-to-weight ratios result in restrictor plates at other tracks. The Goody's Dash Series (known now as the ISCARS series with its new ownership) used restrictor plates at Bristol during at least the last years of the series' existence when the cars were using six-cylinder engines (compared to the traditional four cylinder engines), in addition to their Daytona races. The International Sport Compact Auto Racing Series (ISCARS) (previously known as the NASCAR Baby Grand National, Goodys Dash Series and IPOWER Dash Series among others) is a stock car racing series created by NASCAR in 1975 that involved V-6 powered cars raced over relatively short distances. ... Grandstand in 2007 Scoring pilon in August 2007 Sign proclaiming the track the Worlds Fastest Half-Mile in 2007 Bristol Motor Speedway, originally known as Bristol International Raceway and Bristol Raceway is a NASCAR short track located in Bristol, Tennessee. ...

However, restrictor plates are not used for Craftsman Truck Series trucks. Rather, air intake, aerodynamic, and, eventually, a tapered carburetor spacer were implemented for those races. Combined with the aerodynamic disadvantage of the trucks, this allows NASCAR to avoid the use of such equipment for the trucks. The NASCAR Craftsman Truck Series is a popular NASCAR racing series that features modified pickup trucks. ...

The third use came in 2000. Following fatal crashes of Adam Petty and Kenny Irwin, Jr. at the New Hampshire International Speedway during the May Busch Series and July Cup Series races, NASCAR adopted Modified rules featuring a one-inch (2.54 cm) restrictor plate to slow the cars headed towards the tight turns as part of a series of reforms to alleviate stuck throttle problems which were alleged to have caused both fatal crashes. For the Cup race, it was used just once at the 2000 Dura-Lube/Kmart 300, allowing Jeff Burton to dominate by leading all 300 laps in the ensuing race. Due to the lack of passing and the addition of an automatic kill switch in the case of a stuck throttle, the use of restrictor plates, intended as an emergency measure pending a more permanent replacement in any event, was discontinued at New Hampshire for the following race for Cup only. However, the Modifieds still use a restrictor plate, especially with the numerous deaths of star drivers in the history of the Whelen Modified Tour, yet no driver has died in the WMT at NHIS. Adam Kyler Petty (July 10, 1980 – May 12, 2000) was an auto racing car driver. ... Kenny Irwin, Jr. ... New Hampshire International Speedway is a 1. ... Most recent champion(s) Kevin Harvick The NASCAR Busch Series is a stock car racing series owned and operated by NASCAR. It is NASCARs minor league circuit (often compared to Triple-A baseball), and is a proving ground for drivers who wish to step up to the organizations... The NEXTEL Cup Series is NASCARs top racing series. ... (The NASCAR Whelen Modified Tour was previously named NASCAR Winston Modified Tour and NASCAR Featherlite Modified Series) The NASCAR Whelen Modified Tour (WMT) is a stock car racing series owned and operated by NASCAR in the Modified division. ... The Sylvania 300 is a NASCAR Nextel Cup stock car race held at the New Hampshire International Speedway in Loudon, New Hampshire. ...

Rusty Wallace tested a car at Talladega Superspeedway without a restrictor plate in 2004, reaching a top speed of 228 mph (367 km/h) in the backstretch and a one-lap average of 221 mph (356 km/h). ^[1] Wallace subsequently described the experience as "out of control". Rusty Wallace on his way to his 55th and final victory in the 2004 Advance Auto Parts 500 at Martinsville Speedway. ... Talladega Superspeedway is a motorsports complex located in Talladega, Alabama. ...

References