EFI Buyer's Guide - Fueling Around

Many people think fuel injection is akin to the dark arts, like Voodoo or something, but it's not really that scary if you understand the basics of how an electronic fuel injection (EFI) system works. Without sounding like geeks in white lab coats, EFI is, essentially, a more precise way to control the fuel requirements of an engine. Where a carburetor is sized to an engine by its cfm rating and certain sized fuel jets are used to control fuel flow to the engine, EFI does the same thing via the cfm rating of its inlet, called a throttle body, and by the EFI's fuel injectors. Think of the injectors as an electronic version of a carb jet, only they can vary in size, making the EFI system more precise for the engine's fuel demands.

While we're over simplifying the typical EFI system here, we're just trying to help those who feel EFI is out of their range of comprehension by doing exactly that, keeping it simple. A whole separate story could be written on EFI theory (frankly whole books have been written on it) and if we really wanted to scare you we could talk about building, literally, with a circuit board and soldering iron, your own EFI computer. But that's not what we want to do. We want to put your mind at ease when it comes to EFI systems, which is why we're going to concentrate on easy-to-install, complete EFI conversion kits only for this buyer's guide.

A lot of technology and ingenuity have gone into the latest EFI systems. Just a few short years ago, many of the top aftermarket EFI systems were pretty much race oriented and required a laptop to even get the car started, let alone running at peak efficiency (hmm, maybe that's where all the scariness about EFI comes from). Today you can easily bolt on a manifold (or in some cases just a throttle body to your existing manifold); plumb some fuel system upgrades, and hook up a couple of wires. You can literally have some of these fuel injection systems up and running in less than a day with great benefits, including lower emissions, better fuel economy, easier starting, and more performance. For our buyer's guide, we scoured the market for complete bolt-on systems that featured either self-tuning capabilities, or came with their own handheld tuner so that no laptop or special software is required to get these systems up and running on your classic Ford. Check 'em out and join the 21st century!

Accel DFI

(216) 688-8300
www.accel-ignition.com

Edelbrock

Edelbrock's new Pro-Flo XT EFI systems use the same electronics, including the handheld controller, but that's where the similarities end. The Pro-Flo XT features a more modern look with an OE-style long-runner intake and large 90mm front-mount throttle body. The wiring harness on the Pro-Flo XT also includes a bulkhead connector for easy disconnection and removal for servicing the engine or for engine removal.

(800) 416-8628
www.edelbrock.com

FAST (Fuel Air Spark Technology)

(877) 334-8355
www.fuelairspark.com

Holley

(800) HOLLEY-1
www.holley.com

Inglese

(866) 450-8089
www.inglese.com

Mass-Flo EFI

(336) 644-8668
www.massfloefi.com

Professional Products

(323) 779-2020
www.professional-products.com

Powerjection II is a multi-port system on a carbureted type manifold, while Powerjection III is a unique throttle body system that, at first glance, looks like your typical performance carburetor

When it comes to small-block... 

   

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When it comes to small-block Fords, stack system options are out there, but as you get up into the big-block engines and the new modulars, choices become fewer and fewer. If you’re a big-block kind of guy (or gal) and just have to have EFI stacks for your 460 (like the Ford Racing crate engine shown in this Factory Five Roadster kit built by VCP), or you want the ultimate modular engine with stacks, VCP is the place to call.

Very Cool Parts

(760) 403-6266
www.verycoolparts.com

Fueling Around

Although some of the EFI systems we've just profiled either come with a fuel system or at least a fuel pump, most leave the fuel system up to the builder. With that said, we thought a bit of a primer (sorry, couldn't help myself on the pun!) would be in order as to choosing EFI-type fuel system components.

First off, while the typical EFI system runs at about 40 psi of pressure, nearly 10 times that of your carbureted setup, it's still designed to do the same thing, which is deliver the proper amount of fuel for the demand of the engine. In the case of EFI, the engine's demand is calculated by a series of sensors that give the ECM enough data to determine the opening and closing rates of the fuel injectors at a specific fuel pressure. Thus, the pressure needs to be right (as well as the volume of fuel) otherwise you can have a lean condition, which is not good.

Starting at the fuel pump, you can find EFI pumps in two basic configurations: in-tank, and external tank setups. In-tank is like your OE late-model daily driver, with the pump mounted inside the tank where it's cooled by the fuel around it. This setup is a bit harder to work out in a vintage car, but there are solutions through aftermarket companies to put the EFI fuel pump inside the tank. This is usually considered the best solution, as the pump lasts longer, is quieter, and isn't susceptible to fuel level issues and/or hard cornering when the tank is low on fuel.

The external pump mounts on the framerail or similar location of the chassis, so right off the bat the first consideration is mounting space/location where it will not interfere with moving suspension parts or be too close to a hot exhaust system. External pumps must be mounted below the fuel level of the tank, often making the pump one of the lowest parts of the car's profile. External EFI fuel pumps do not like to "suck" the fuel, but should be gravity fed, hence the importance of mounting location.

For fuel lines, the typical EFI system requires a feed line to the EFI manifold and a return line back to the tank. Generally, the return line is sized smaller than the feed line, as there is little pressure in the return line. Most builders simply run the same size line for both. Like a carburetor, with more power you want bigger lines. We suggest 3?8-inch ID or -6 AN line for both the feed and return. Any restriction in the return line can cause pressure issues with the EFI system, so ensure your return line has nearly zero pressure in it. If you use a rubber line for any portion of the fuel line, ensure it's rated for EFI use due to the pressure seen in these systems. Typical braided AN line or push-on hose is good for 300 psi of working pressure, but if you're plumbing from a stock vintage Ford fuel pickup to an external pump or filter and need to use regular hose and clamps, it must be EFI-rated and be sure to use EFI-type hose clamps, as they don't cut into the hose when tightened.

Finally, you'll need a fuel pressure regulator, and for good measure, grab a 0-50 or 0-100 EFI-rated pressure gauge for your build as well. The regulator is used to regulate the fuel pressure at the throttle body or fuel rails. As noted earlier, working pressure is usually 40 psi, but some systems can be tuned to higher horsepower capacity by raising the fuel pressure, providing your fuel pump has enough capacity in both pressure and volume. A typical two-port bypass regulator will fit the bill, allowing the feed line to feed the regulator's IN port, the OUT port will then feed the throttle body or fuel rails, while the regulator's return port (usually marked RET) will return the unused fuel back to your fuel tank. We'll take a more in-depth look at EFI fuel systems and building the proper system in an upcoming issue.