Updating Induction Systems with EFI

Feeding fuel to a hot rod requires not only solid science, but also a sense of style. Since the induction system sits right on top of the engine, it's the first thing everybody notices when you open the hood. If it doesn't look cool, most hot rodders could care less how well it works. So when it comes to installing a modern electronic fuel injection (EFI) system, half the battle is making it visually pleasing.

Art Meets Science
"The biggest challenge is hiding injectors, when customers don't want the EFI system to be seen," admits Dan Fodge of Fodge Engineering, a firm that specializes in custom EFI for hot rods, musclecars and street rods. "They don't like wires and lines; they want you to make it look clean."


Just because you like the benefits of EFI doesn't mean you have to give up form for function. It's really amazing how many different types of setups can be done. "Fortunately, the EFI computer doesn't care what the intake is—we can fuel-inject anything," Fodge adds. Even though the basic EFI system is fairly similar for all engines—a collection of various sensors feeds data to a computer that controls the timing of the fuel injectors—how EFI actually fits onto intake systems varies widely, and that's where art and science converge. To show how they can comfortably coexist, we've provided an overview of several different configurations and their specific applications.

Applications
In addition to the basic system components, you can see EFI fitted to engines with port systems, throttle bodies, stacks, blowers, cross-ram, and tunnel-ram induction systems. Today, EFI systems can be adapted to just about any engine, from a flat head to an LS1. Prices vary with the system involved, but a custom unit can range anywhere from $4,000 to as high as $9,000 for a race-ready induction system.


Whatever induction system you choose, EFI can handle them all, because, as Fodge sums up, "The bottom line is pulse width." In other words, the engine's performance is determined entirely by how long the injectors fire (at idle, the pulse is usually about 2.5 milliseconds, accelerating to 12 to 15 milliseconds for wide-open throttle). No matter what sort of flow and air/fuel characteristics a given intake system has, the timing in microseconds on the injector firing keeps the engine in precise tune, which is all controlled by the computer. Even though the EFI's brain box may look the same on two different engines, it can be programmed to handle completely different types of injection, such as batch-firing, bank-to-bank or sequential. For most street applications, bank-to-bank is the most cost-effective way to go.