21. Here’s a good visual representation of what the Edelbrock self-learning fuel system does. The top jagged line is the engine’s air/fuel ratio on our first dyno pull—it’s all over the place, since the ECU is trying to determine how much fuel the engine needs to run smoothly. The lower line is the AFR on our second pull -- much smoother and more stable across the RPM range. This was done 100 percent automatically by Edelbrock’s software.