Fuel Injection Comes to NASCAR
CONCORD, N.C. — Simply put, NASCAR's move to electronic fuel injection hasn't gotten the press it deserves.
There have been more pressing concerns. The sanctioning body and Sprint Cup teams were so focused on rule changes designed to break up sustained two-car drafts during mid-January tests at Daytona International Speedway that the impending competitive debut of EFI went virtually unnoticed.
Nevertheless, the introduction of EFI represents a profound change that goes far beyond bringing Cup race cars closer to models found in the showroom. Here are the basics:
-- The fuel delivery system is fundamentally different. Injectors shoot fuel into each individual cylinder, as they are programmed to do by computer. Instead of a carburetor that mixes air and fuel, a throttle body provides airflow to the engine. As Sprint Cup series director John Darby put it during a meeting with reporters Monday at NASCAR's research-and-development center, "The engine architecture is the same. We're squirting it (fuel), instead of sucking it."
-- There are more parts and pieces. To run the EFI system, NASCAR has contracted with McLaren to provide an electronic control unit, powered by software from Freescale. An array of sensors provides performance data to the ECU, which is mounted on the engine. With a few keystrokes on a laptop computer, engine tuners can construct an ignition timing map that will regulate fuel flow to the cylinders based on input from the sensors.
The implications for Cup racing are far-reaching. Teams can plug into the ECU post-race and use the after-the-fact telemetry to make performance decisions. Traditionally, NASCAR has taken a firm stance against real-time data acquisition, and that won't change.
But teams will be allowed to download data after practice and qualifying and make adjustments to the EFI system. What they won't be able to do, however, is read data during a race, and — realizing that fuel mileage may determine the outcome, for example — reset their systems to a mapping more conducive to fuel conservation.Continued on the next page