If there's one thing that's critical in a high performance engine, then it's
fuel control. Think about it: the whole objective of adding a turbocharger, of installing NOS, even of installing a free flow exhaust system, is to improve fuel delivery into the combustion chamber. It is also events in the combustion chamber that can and will destroy a high performance race engine if it's not controlled properly. Here we're talking about controlling the combustion process. Now I've heard many arguments as to why sidedraft carburetors provide better performance than fuel injection and engine management, and vice versa but I always say: it's not about performance, it's about reliability and there's no better system for fuel control than electronic fuel injection. Any endurance race car from
INDY Car Racing, to
Formula 1, to the
World Rally Championship, to the
Le Mans Series uses electronic fuel injection (EFI) systems, not just for reliability but because ensuring that the correct amount of fuel is delivered under every condition, will provide the best performance.
EFI is central to engine management. It relies on an
engine control unit (ECU) which processes a number of inputs from various sensors on the engine to deliver the correct amount of fuel at a particular RPM and air-flow rate/air density combination. The fuel is delivered through an
injector, which is an electronically actuated solenoid valve. The amount of fuel that is delivered is dependent on the fuel pressure, which is usually a constant
30 psi above intake manifold pressure, and the
pulse duration of the injector, i.e., the length of time the injector is held open.
Most EFI systems have a standard set of sensors. These include:
