In previous issues, we've discussed some of the benefits of a quality aftermarket fuel injection system. As we've implied, simply converting from a carbureted system to an electronic fuel injection setup doesn't necessarily mean you're going to gain significant horsepower, but it does allow you to manipulate every parameter of the engine's functionality, which provides an infinite level of tuning for maximum performance. With a little fine-tuning, you can expect easier cold starts, increased fuel mileage, smooth idle, and exceptional part- and full-throttle quality from even the most radical combinations.
Converting to EFI may seem like a daunting task, especially if you're used to tuning a carburetor with a screwdriver. Although the concept is the same, which is to require similar air/fuel ratios for optimum power, all the mechanical hardware is replaced with computerized maps that match engine load and rpm with numbers. Fortunately, electronic fuel management systems like the ACCEL/DFI unit comes with a user-friendly CalMap calibration software to help you get started with minimal effort.
ACCEL's latest Gen-VII digital EFI system is available in several different configurations, from basic to extensive. The most basic systems include the engine control module (ECU); engine harness; MAP, TPS, IAT, ECT, and MST sensors; the CalMap software with an interface cable; and the instruction booklet. Accel also offers a bolt-in system for both big- and small-block conversions that includes its proprietary Pro-Ram manifold with machined billet aluminum fuelrails; stainless braided crossover tubes; an adjustable fuel regulator; CNC-machined, billet aluminum throttle-bodies (choice of 4150 or 4500 flange that flow from 750, 1,000, and 1,200 cfm); idle air control motor; high-output fuel pump; stainless fuel filter; all manifold fittings; throttle bracket; and high-performance fuel injectors.
There's also a complete Plug-n-Play system specifically calibrated for various crate-engine combinations, such as those offered from GM Performance Parts, and requires no tuning whatsoever. In fact, these systems come completely programmed from ACCEL, based on both engine dyno and real-world vehicle testing. That means you'll only have to find a place to mount the ECU, plug it in, and you're ready to go. About the most difficult procedure, if you can call it that, is to set the throttle-position sensor (TPS) for wide-open throttle. Simply turn the ignition key on (engine off), hit the corresponding key on the laptop, floor the throttle, and hit the key again to complete the procedure. And should you ever decide to upgrade the camshaft, heads, or manifold, you'll be happy to know that the system can be easily upgraded to take advantage of the added air.
Regardless of your setup, ACCEL/DFI can create a custom program for your specific application, making it even easier to get the engine fired up the first time. And if that isn't enough, the Gen VII includes a volumetric efficiency (VE) estimator that can create a basic VE table, eliminating any guesswork when determining a start-up fuel map. You'll need to fine-tune the VE table for peak power, and the map generated by the Gen VII will get you fairly close. Another invaluable tuning tool is ACCEL's wide-band oxygen sensor. While not everyone will need one, it's certainly an important tuning aid that'll accurately monitor air/fuel ratios when adjusting the fuel mixture.
While we've only scratched the surface on how powerful the ECU is with its various utilities and optional accessories, we'll prove it in the next couple of months. We're already tearing apart our 496ci big-block (see "The Fatter-Block!" Jan. '05) and plan on throwing a fairly stout huffer, namely a ProCharger F-2, on top of it with an air-to-air intercooler and shooting for some big numbers on pump gas. Combined with the Gen VII, we're going to show how a brutal mule can be toned down and made streetable with a few simple keystrokes. So whether you're looking for the easiest way to convert to EFI or need an EFI system that's capable of supporting copious power, have comfort in knowing that ACCEL/DFI can fulfill your needs. CHP