How NASCAR Engines Work

NASCAR Engine Rules

In NASCAR, technology is similar to an arms race. That is, teams are constantly looking for innovations that will make their cars faster and better than the rest of the field. However, if any one team finds too big of an advantage and starts winning too easily, that makes racing predictable and boring to the fans. Bored fans mean empty grandstand seats, which means less revenue.

Understandably, NASCAR goes to some pretty extreme lengths to ensure a level playing field. At the end of a race, you might see the driver spraying champagne on teammates and perhaps giving a quick on-camera interview. However, the day is far from over for the exhausted winning team. NASCAR officials then roll the winning car away and conduct a teardown, or dismantling, of the vehicle. This can include a complete disassembly of the engine, suspension system or anything else that the officials choose to inspect. They're looking for any irregularity, such as forbidden parts or measurements, which might unfairly enhance performance.


­Teams can and do take certain liberties with engine design, but a few NASCAR rules are quite rigid. The engine, for example, must be a carbureted V-8 with an iron block. NASCAR places strict limits, for instance, on how engine cylinders are bored -- that is, how they're made larger by removing material. NASCAR also requires teams to use blocks, cylinders and intake manifolds made from castings of approved manufacturers. The mandatory Car of Tomorrow design, mentioned earlier, standardizes engines even further.

These rules are clearly spelled out in NASCAR guidelines, yet there are often disputes between teams and officials about their interpretation of these rules. Teams can become quite inventive in finding ways to bypass the limitations imposed by a rule, only to have NASCAR become more specific and stringent with its language to eliminate the advantage [source: Martin]. This is one reason why stock cars are so uniform in dimension. The bodies have similar shapes and aerodynamic properties because they must conform to certain templates, or patterns mandated by NASCAR to ensure a consistent car size and shape. NASCAR maintains an equally explicit list of interior features that cars must have for both safety and to promote a reasonably level playing field.

­Now that we've got some of those pesky rules out of the way, we can look at some of the technologies that make NASCAR engines such powerful beasts.