Restrictor plates

Restrictor plates are devices installed between the carburetor and intake manifold that restrict the amount of air and fuel entering the engine's combustion chamber.

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The device limits the power output of the motor and hence slows both the acceleration and the overall top speeds obtainable on the tracks where the cars are so equipped. These restrictions are supposedly in the interest of driver and fan safety, although many members of both of those groups feel that the close packing 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 those races. Such crashes are dubbed "the big one" by drivers and fans and usually happen once per race, if it does happen. (On rare occasions there are multiple such incidents, or on even rarer occasions, none.) It certainly makes for a different style of racing at these events than that which occurs at the other superspeedways used by NASCAR, as reduced power makes it more difficult to pass other drivers.

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Drivers often form long chains, which, due to the lack of air resistance, typically travel faster than single cars. This type of racing is often referred to by fans, drivers, and crew members alike as restrictor plate racing.

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Restrictor plates have been used three times in NASCAR history.

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The first use came in 1971 as part of NASCAR's plans to reduce the size of engines from 427 cubic inches (7.0 liters) to 358 cubic inches (5.87 liters). In order to allow teams with smaller budgets to race the larger engines, NASCAR imposed a restrictor plate to be placed on the larger engines to equalize the performance with the smaller engines. The transition ended in 1974, when NASCAR banned the larger engines, and went to the current 358 cubic inch formula. This was a transitional process, and as not every car used restrictor plates, this is not what most fans call "restrictor plate racing".

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The second use came following the terrifying crash of Bobby Allison at the 1987 Talladega events. NASCAR imposed restrictor plates again, this time at the two fastest circuits, both superspeedways, Daytona and Talladega. This usage continues to the present day for all races at these tracks, including the Daytona 500.

Related Topics:
Bobby Allison - Superspeedway - Daytona - Talladega - Daytona 500

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The third use came in 2000. Following fatal crashes at the New Hampshire International Speedway during the May Busch Series and July Cup Series races, NASCAR imposed restrictor plates for Cup cars 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. The plates, used in Whelen Modified Tour races at the circuit, were used just once in the Cup series, for the 2000 New Hampshire 300, and created a dominating race for Jeff Burton, who led 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 was discontinued at New Hampshire for the following race.

Related Topics:
New Hampshire International Speedway - Whelen Modified Tour - New Hampshire 300

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