In the past, Sunoco Green E15 mixed with air to power the engines at the carburetor. But with EFI, that process changed. Now, multiple-port EFI injects fuel into each “intake runner” and mixes it with air. A combination of sensors and a Freescale/McLaren ECU (Electric Control Unit) makes the engine more efficient.

EFI: The setup
Laptop computers help crew chiefs and engine technicians read data provided by the ECUs before the race. During the race, the fuel injection system technology adjusts itself, eliminating the need for teams to monitor the data.

EFI: Restrictor plates
NASCAR requires EFI engines to use a restrictor plate at Talladega and Daytona. It is placed beneath the EFI throttle body and limits the amount of air available to the engine. Unlike carbureted engines, Sunoco Green E15 will not pass through a restrictor plate opening.

EFI: Key parts/partners

1.     Freescale/McLaren Electronic Control Unit (ECU)

2.     Holley EFI throttle body

3.     Bosch O2 Sensors

4.     Other sensors

5.     Fuel injectors

6.     Ignition coils 

7.     Spark plugs