| The original concept of a NASCAR race car was that | | | | Talledega, Alabama. Fans were injured in the stands |
| is was supposed to be composed of stock parts you | | | | and NASCAR took action to restrict the speed of |
| would buy in an auto parts store. In some respects | | | | the vehicle through what is known as a restrictor |
| that is true but not totally. The race car is a high | | | | plate. This also gave birth to the term restrictor-plate |
| performance racing machine designed to withstand | | | | racing. |
| high G-forces when banking on turns. Lets look at | | | | The physics of the restrictor plate have to do with |
| what makes up this vehicle. | | | | reducing air intake into the intake manifold of the |
| The first component most are interested in is the | | | | engine. Less air will result in lower combustion thus |
| engine of a NASCAR racing vehicle. This engine | | | | reducing horsepower. The restrictor plate is a sheet |
| actually is very close to that which you have in your | | | | of metal with four holes bored in it at precise |
| car (provided you have a big engine) but it is | | | | tolerances. The plate is then mounted between the |
| customized so that it can withstand high temperature | | | | intake manifold and the carburetor. After that, the |
| and torque. All parts in the engine of a are machined | | | | NASCAR vehicle should not be able to exceed |
| to within very tight specifications so that there is a | | | | speeds of 200 mph. |
| minimum of friction. The carburetor is designed to let | | | | It would seem like the restrictor plate would resolve |
| in the volume of air and fuel mixture required to | | | | the safety problem but many professional drivers |
| sustain high speeds for lengthy spans of time. There | | | | have been asserting that it creates more potentially |
| are no fuel injectors in the race cars engine. | | | | unsafe situations in a race. If you think about the |
| The first modification to the NASCAR vehicle was to | | | | difference between a motor scooter and a |
| smooth out the ride. Early races were run on tracks | | | | motorcycle you can see where a restrictor plate |
| that were very bumpy and this causes a lot of | | | | could create problems. Many times a motor scooter |
| damage. Today, the NASCAR vehicle is basically a | | | | has an accident where a motorcycle could have |
| body molded from sheet metal on a frame | | | | avoided it because of its increased ability to |
| supported on the inside by bars made of sheet | | | | accelerate (a motorcycle can accelerate quicker to |
| tubing. The vehicle is not a stock vehicle any longer | | | | avoid an oncoming threat). It is the same complaint |
| as each component is hand-crafted and assembled. | | | | among almost all of the racers with restrictor plates. |
| The car is built with safety in mind while giving it the | | | | They have identified situations where the cars bunch |
| ability to maintain speeds approaching 200 mph. Driver | | | | up and the driver only has one choice and that is to |
| comfort is not the focus. | | | | slow down. Speeding up to avoid the congestion is |
| The NASCAR vehicle at one time was able to reach | | | | not an option because the other cars may be at the |
| speeds in excess of 200 mph and that all changed in | | | | restrictor plate limit too. |
| 1987 when Bobby Allisons race car flew into a | | | | But as for now, the restrictor plate is a requirement |
| section of fence at the Talladega Speedway in | | | | in the race car vehicle on the majority of tracks. |