Mark Houlahan
Brand Manager, Mustang Monthly
October 25, 2011
Photos By: Courtesy the Manufacturers

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

ACCEL has made a name for itself over the years with its custom programmable EFI system called Digital Fuel Injection (DFI). Now in its seventh generation, the Gen 7 DFI is a very capable and customizable speed density-based engine management system. The Gen 7 DFI electronics allow batch and sequential fire port injection and throttle body injection with individual cylinder control, along with coil-on-plug, coil pack, or single coil ignition setups. Many advanced features include boost controls, nitrous controls, two-step rev limiting, and more-all through an easy-to-use graphic interface software you install on your laptop. ACCEL's latest engine management, the Thruster EFI, offers plenty of user adjustable tuning features and is the backbone of its new engine builder plug-and-play packages.

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

Eight-Stack EFI
ApplicationFord 289/302, 351W, and 351C small-block, 429/460 and FE big-block, 4.6L DOHC modular
System Description50mm throttle bodies on cast manifold, fuel injectors, fuel rails, linkage, harness, ECM and software
Ignition System IncludedMust provide distributor and coil, with Redline and Electromotive management it is complete with coil packs and crank trigger
Fuel System IncludedMust provide fuel pump, fuel filters, fuel pressure regulator, lines, and fittings
Horsepower LevelUp to 650 hp
Optionsstack filters, dyno tuning
Retail PriceStarting at $5,195

Thruster EFI Engine Builder Kit
ApplicationFord 289/302 and 351W small-block
System DescriptionSequential multi-port EFI on a single-plane intake manifold with billet throttle body, high-flow injectors, billet fuel rails, wideband O2 sensor, ECM, and wiring, built-in data logging
Ignition System IncludedDual sync distributor, DFI 6A ignition, DFI E-core coil
Fuel System IncludedFuel pump, DFI billet fuel pressure regulator, most provide own lines
Horsepower Level475-700 hp
OptionsElectric fan control, custom built orders
Retail Price$4,147.95-$4,620.95

Edelbrock

The Edelbrock Pro-Flo 2 EFI systems are complete, fully sequential, EFI systems designed to convert from a carburetor to the efficiency of fuel injection in one kit. Edelbrock's Pro-Flo 2- and XT-based EFI systems include a handheld controller for easy setup and tuning, yet can still be optionally tuned via laptop if the user so chooses. Edelbrock even has the capability of its support staff "seeing" your software calibration during a support session. The EFI system comes with two different tuning strategies built in, speed density (engine speed vs. manifold pressure) and Alpha-N (engine speed vs. throttle position) and even base calibrations to get your Ford up and running quickly. The system uses an included narrow-band O2 sensor and is wideband O2 sensor compatible.

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

Pro-Flo XT Multi-Point EFI
ApplicationFord 289/302 small-block
System DescriptionLong-runner intake manifold, 90mm throttle body assembly, fuel rails, 29- or 44-lb/hr injectors, wiring harness, ECM, handheld calibration module, software
Ignition System IncludedMallory distributor, must provide your own coil
Fuel System IncludedFuel pump, fuel filter, fittings, and lines
Horsepower LevelUp to 450 hp with 29-lb/hr injectors, up to 650 hp with 44-lb/hr injectors
OptionsAs cast or black powdercoated manifold, larger injectors, larger fuel pump, coil-on-plug conversion
Retail Price$4,309.95-$4,569.95

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Pro-Flo 2 Multi-Point EFI
ApplicationFord 289/302 and 351W small-block, 390-428 FE big-block
System DescriptionIntake manifold, throttle body assembly, fuel rails, 29- or 44-lb/hr injectors, wiring harness, ECM, handheld calibration module, software
Ignition System IncludedMSD (small-block) or Mallory (big-block) distributor, must provide your own coil
Fuel System IncludedFuel pump, fuel filter, fittings, and lines
Horsepower LevelUp to 450 hp with 29-lb/hr injectors, up to 650 hp with 44-lb/hr injectors
Optionslarger injectors, larger fuel pump, coil on plug conversion
Retail Price$3,359.95-$4,111.99

FAST (Fuel Air Spark Technology)

Walk through the pits of most any Sportsman racing event and you're bound to find FAST EFI equipment in many of the race cars. The FAST XFI systems feature a broad range of operating parameters, options, and scalability. The XFI system is available with Ford wiring harnesses and ignition adapters for the late-model TFI-style distributor, but because it's purchased in kit form, we're going to limit the XFI system to this mention here, but if you need the laptop tuning ability and customization, the XFI system should be on your list of EFI systems to look at. With that said, the folks at FAST know that the XFI system can be a bit challenging for the bolt-on crowd that simply wants to yank their carb off, go EFI, and reap all the benefits. That's why FAST has developed its EZ-EFI self-tuning EFI systems. On the market just a few short years, the EZ-EFI is available as a throttle body system, complete multi-port system, and even a multi-port retrofit to use with a factory manifold setup (great for swapping a factory EFI 5.0L Mustang engine into a classic). All EZ-EFI systems are speed density based.

(877) 334-8355
www.fuelairspark.com

EZ-EFI 4150-Based EFI
ApplicationAny 4150-style flange intake manifold
System Description4150 carb flange throttle body with built-in fuel rails and 88-lb/hr injectors, wiring harness, ECM, handheld calibration module, wideband O2 sensor (Master Kit includes fuel pump, filter, lines, and fittings)
Ignition System IncludedMust provide your own distributor and coil
Fuel System IncludedOnly included with Master Kit system
Horsepower LevelUp to 550 hp, dual quad option supports over 1,000 hp
OptionsDual quad kit, fuel pump kit, universal in-tank fuel pump kit, multi-port retrofit
Retail Price$1,802.45-$2,371.23

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EZ-EFI Multi-Port EFI
ApplicationFord 289/302 and 351W small-block
System DescriptionSingle-plane intake manifold, billet throttle body assembly, fuel rails, injectors, wiring harness, ECM, handheld calibration module, and fuel pump kit
Ignition System IncludedMust provide your own distributor and coil
Fuel System IncludedIncludes fuel pump and fuel filters, must provide fittings and lines
Horsepower LevelUp to 1,000 hp
OptionsFuel pump hose and fitting kit
Retail Price$2,667.39-$3,593.51

Holley

With a name like Holley, synonymous with fuel delivery, you know Holley has something to offer for aftermarket bolt-on EFI systems. Indeed, Holley has been involved with EFI systems for decades and has recently relaunched its aftermarket EFI business under the umbrella of "Holley EFI" with several sub-families of EFI packages. We're mostly concerned with the Avenger and HP lines of EFI, as its Dominator line; while more than capable of running a street engine is not a whole-system solution, which is what we're focusing on in this guide. The Avenger and HP lines feature throttle body and multi-port EFI systems. The Avenger and HP EFI systems are speed density based and both feature self-tuning capabilities and utilize a handheld programmer for tuning inputs should you feel the need to adjust a parameter yourself. Additionally, the HP-based systems offer enhanced features like nitrous retard, boost control, distributorless ignition driver, water/meth injection control, internal data logging, and much more.

(800) HOLLEY-1
www.holley.com

Avenger EFI 2/4BBL TBI
ApplicationAny 4150-style flange intake manifold
System Description670- to 900-cfm cast throttle body assembly, injectors, wiring harness, ECM, handheld calibration module, wideband O2 sensor, and fuel pump kit
Ignition System IncludedMust provide your own distributor and coil
Fuel System IncludedIncludes fuel pump and fuel filters, must provide fittings and return line
Horsepower Level200-600 hp
OptionsUpgrade to HP-based ECU, oil and fuel pressure transducers
Retail Price$1,799-$1,999

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HP EFI Universal Multi-Port Retrofit
ApplicationAny 4150- or 4500-style flange intake manifold
System Description900-cfm cast throttle body assembly, wiring harness, fuel rails, fuel injector bungs, fuel pressure regulator, ECM, and wideband O2 sensor
Ignition System IncludedMust provide your own distributor and coil
Fuel System IncludedIncludes pressure regulator, must provide fuel pump, fuel filters, fittings, lines, and properly sized injectors
Horsepower LevelDependent upon injector size
OptionsFuel pumps, injectors, Ford TFI ignition adapter, oil and fuel pressure transducers, knock sensor
Retail Price$1,849

HP EFI 4BBL TBI
ApplicationAny 4150-style flange intake manifold
System Description900-cfm cast throttle body assembly, 75- or 85-lb/hr injectors, wiring harness, ECM, handheld calibration module, and wideband O2 sensor
Ignition System IncludedMust provide your own distributor and coil
Fuel System IncludedFilters included, must provide your own fuel pump
Horsepower LevelUp to 525 hp (75-lb/hr injector), up to 600 hp (85-lb/hr injector)
OptionsKnock sensor, oil and fuel pressure transducers, 5.7-inch touchscreen controller, Ford TFI ignition adapter
Retail Price$1,749

Inglese

If there's one induction setup that stops people in their tracks, it's an eight-stack system. From Shelby Cobras to altered-wheelbase race cars of the '60s, stacks told people you meant business-and they just looked cool! Problem was you were essentially running four two-barrel carburetors. If you think tuning one carb can be a hassle, try getting all of those carbs to play nice with each other. Today, you can have the sweetest looking engine in town with the efficiency of EFI. Inglese, a name synonymous with eight-stack induction, is now part of the Comp Performance Group (Comp Cams, FAST, RHS, ZEX, and others). Working with its sister company, FAST, Inglese was able to build a simple-to-install EFI system using the FAST EZ-EFI electronics with special EFI throttle bodies that look just like the old-school Weber carbs. So now you can have your cake and eat it too!

(866) 450-8089
www.inglese.com

EZ-EFI Eight Stack
ApplicationFord 289/302 and 351W small-block
System DescriptionIndividual 50mm throttle bodies on cast single-plane intake manifold, fuel rails, wiring harness, ECM, handheld calibration module, Dual Sync distributor
Ignition System IncludedMust provide your own coil
Fuel System IncludedMust provide fuel pump, filters, lines, fittings, and injectors
Horsepower LevelUp to 1,000 hp
OptionsFuel pump kits, fuel injectors, polished and brushed stacks in 50mm and 100mm lengths
Retail Price$3,968.24

Mass-Flo EFI

So far the EFI systems we've reviewed here have been speed density based, meaning they calculate the fuel demand via engine speed and manifold absolute pressure. Where Mass-Flo EFI differs (though the name kind of gives it away) is that it uses a mass air meter just like the OE systems on your late-model Mustang or daily driver to calculate engine load. This makes your EFI system much more flexible and can "see" engine changes such as cam swaps, head porting, and more. There's no handheld controller or laptop connection because none is needed. Mass-Flo EFI also bucks the trend of using Bosh or GM sensors and actually uses Ford sensors. OE parts you can get service replacements as close as your nearest parts store. The OE Ford ECM that drives your late-model Mustang is similar to what Mass-Flo uses for OE reliability, and if you really want to, you can custom tune the ECM via any reputable Ford chip tuner. Multi-port injection, OE sensors, mass air meter calculation, and even a retro look are part of Mass-Flo's EFI packages.

(336) 644-8668
www.massfloefi.com

Mass-Flo EFI
ApplicationFord 289/302, 351W, and 351C small-block; 429, 460, and FE big-block; 4.6L and 5.4L modular
System Description1,000-cfm billet throttle body on cast single-plane intake manifold, fuel rails, wiring harness, ECM, injectors sized to your engine, distributor, ignition coil, mass air meter assembly
Ignition System IncludedDirect plug-in Mallory distributor and matching coil
Fuel System IncludedMust provide fuel pump, filters, lines, and fittings
Horsepower LevelUp to 1,100 hp
OptionsFuel pump kits, fuel injectors, mass-air meters
Retail Price$2,994.99-$3,994.99

Professional Products

Low-cost performance intake manifolds, both for carbureted and EFI applications, have been Professional Products' claim to fame from the onset of the company. Over the years, Professional Products has expanded its line of hardware to include dampers, distributors, fuel system components, and more. The Powerjection EFI systems come in two flavors: 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. Either system will work with a traditional air cleaner assembly for that stealth/retro look many classic car owners are looking for. Both Powerjection systems feature a self tuning Stage 3 ECM and a wideband O2 sensor with easy install exhaust clamp assembly (no welding required).

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

Powerjection III
ApplicationAny 4150-style flange intake manifold
System Description750-cfm cast throttle body, 62-lb/hr fuel injectors, wiring harness, ECM, and wideband O2 sensor
Ignition System IncludedMust provide distributor and coil
Fuel System IncludedFuel pump, fuel filter, fuel pressure regulator, and fittings (supplied in complete kit only)
Horsepower LevelUp to 550 hp
OptionsFuel pumps, Fuel on Demand returnless fuel system module (eliminates need for return line), feed and return fuel line and fitting kit
Retail Price$1,599.95-$2,099.95

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Powerjection II
ApplicationFord 289/302 and 351W small-block
System Description1,200-cfm cast throttle body on cast single-plane satin or polished intake manifold, fuel rails, 36-lb/hr injectors, wiring harness, ECM, fuel pressure regulator, fuel pump, fuel filter, wide band O2 sensor, and all sensors
Ignition System IncludedMust provide distributor and coil
Fuel System IncludedIncludes pressure regulator, fuel pump, fuel filter, and injectors, must supply fuel return line (unless optioning the Fuel on Demand system)
Horsepower LevelUp to 550 hp
OptionsFuel pumps, Fuel on Demand returnless fuel system module (eliminates need for return line), feed and return line and fitting kit
Retail Price$1,995.95-$2,095.95

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

Very Cool Parts

With a name like Very Cool Parts (VCP) you know that it certainly has a lot to live up to. But fear not, as VCP builds all sorts of shiny engine jewelry us mortals call "stacks" or "stack injection." If you're looking for a stack-type system with all the bells and whistles, custom set up to your engine's particulars, with plenty of build options for engine management, ignition systems, and more, VCP is the place to talk to. This is no off-the-shelf, one-size-fits-all EFI solution. No, the staff at VCP will discuss your engine's power level, your driving style, and more and spec the right hardware to build you the stack system of your dreams.

(760) 403-6266
www.verycoolparts.com

Eight-Stack EFI
ApplicationFord 289/302, 351W, and 351C small-block, 429/460 and FE big-block, 4.6L DOHC modular
System Description50mm throttle bodies on cast manifold, fuel injectors, fuel rails, linkage, harness, ECM and software
Ignition System IncludedMust provide distributor and coil, with Redline and Electromotive management it is complete with coil packs and crank trigger
Fuel System IncludedMust provide fuel pump, fuel filters, fuel pressure regulator, lines, and fittings
Horsepower LevelUp to 650 hp
Optionsstack filters, dyno tuning
Retail PriceStarting at $5,195

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.