Modified Mustangs & FordsHow To Engine
Installing Electronic Fuel Injection
When we arrived at Ed Worthington's shop in Burbank, California, we shook hands with a man whose mind never rests, a fellow who conceives ideas and weaves realistic objectives 24 hours a day. Worthington is enjoying his retirement years these days. However, forget the rocking chair, shuffleboard, and reminiscing about the good old days. Worthington has hotter fish to fry in the here and now, so he invited us to his shop to share the rapidly bending technology curve with us.
In the back of his shop was a well-dressed "FE" Ford big-block--a ´67 390 GT High Performance V-8 topped with Edelbrock aluminum heads and induction, and stuffed full of all the workings necessary to make nearly 600 horsepower and roughly 600 lb-ft of torque from 390 cubic inches. On the open road through an overdrive unit and 3.50:1 gears, Ed predicts 32 mpg in a ´67 Mustang fastback. Who says you can't teach an old 390 passenger car engine new tricks? Certainly not Worthington, who will tell you that his approach, coupled with Speed Pro's Sequential Fuel Injection Management System (SFIMS) from Federal-Mogul Performance, will wake up any vintage Ford V-8 engine, including flatheads and Y-blocks.
Speed Pro's SFIMS was originally conceived by FP Performance Electronics (also known as Fel-Pro) in 1996. When Fel-Pro was acquired by Federal-Mogul in 1998, this system was brought under the Speed-Pro banner.
The beauty of this system is its versatility. You can retrofit current EFI systems with Speed Pro's SFIMS, and you can convert from carburetor to SFIMS. There are two basic SFIMS systems available from Speed Pro. The value-priced "Bank-To-Bank" system fires half the engine's injectors for every 180 degrees of crankshaft rotation. This improves fuel delivery and performance. There is also a provision for nitrous oxide injection or electric cooling fan.
The top-of-the-line Sequential Electronic Fuel Injection (SEFI) system enables performance enthusiasts to custom tune their engines cylinder by cylinder for maximum effectiveness. EFI is the perfect engine management system because it takes a performance picture 3,200 times a second, monitoring throttle position, manifold vacuum, intake temperature, total induction air volume, knock sensing, coolant temperature, and exhaust gas mixture. It checks all these things quickly and adjusts fuel mixture and spark timing faster than you can think. Lean on the accelerator and the ECM (electronic control module) changes the injector pulse width (how long the injector on each cylinder stays open). As we open the throttle, each injector stays open longer to enrichen the fuel/air mixture. Monitored exhaust gas (via O2 sensors) tells the ECM if we're too rich or too lean.
There's more to this than throttle position and exhaust gas condition. If the engine is cold, the coolant temperature sensor gives feedback to the ECM as well, calling for a richer mixture (just like having the choke on with a carburetor) until the engine warms up. Manifold air pressure (MAP) is monitored by the MAP sensor, which tells the ECM what manifold vacuum is. Wide-open throttle means little or no vacuum, meaning we're going to need more fuel. Combine this input with throttle position sensor (TPS) input and the ECM "knows" to increase fuel delivery (by adjusting injector pulse width). The throttle position sensor not only "tells" the ECM that we need more fuel, it also calls for more or less ignition timing. Lay on the gas and you will need advanced spark timing. Back off the throttle and you need a later (or retarded) spark for reduced emissions. The ECM also adjusts idle speed, which no longer has to be adjusted manually.
Ed's formula begins with a single-plane aluminum intake manifold. In this case, it's an old Edelbrock Streetmaster intake from the ´70s. Its uniform intake runners work well with EFI, but any of the Edelbrock Victor series single-plane manifolds will work well today. Because we're installing port-injected EFI, a single-plane manifold is just right for the application. Ed has simply bored holes and installed aluminum injector bungs at each intake port, which points the injectors at the intake valves. Because Ed is a seasoned fabricator, he makes the job look easy. But you can turn your single-plane manifold over to any reputable machine shop for this modification. Each injector bung is either welded or epoxied to the manifold. All must be positioned exactly the same way for uniform performance. The closer you can place the injector to the intake valve, the better.
Because Ed is seeking 600 horsepower, he has chosen Bosch 65 lb-hr fuel injectors, available from most automotive supply houses. These injectors will help the 390 make lots of torque across a broad band, ranging from 2,500 to 6,000 rpm. All eight injectors are tied into the Speed-Pro wiring harness. Even though Ed has chosen Bosch injectors, this doesn't mean you have to. Ford Motorsport SVO and Speed Pro are also excellent sources for fuel injectors. We learned from Ed that you can buy fuel rails by the foot and cut them to fit your application. That's good, considering the size differences between FEs, 385-series big-blocks, Clevelands, flatheads, small-blocks, and Y-blocks. Each side is cut to fit, then injector ports are positioned and drilled at each injector bung. Ed got fancy on us and fabricated pedestals for the injector fuel rails. Each rail is anchored to the aluminum pedestal via Allen screws, which makes for easy injection service. You can polish the injector rails, or you can leave them as they are.
Ed's throttle body is a unique, one-of-a-kind four-throat setup designed specifically for his 390 EFI. However, Coast High Performance has a variety of one-throat EFI throttle bodies, ranging from 65mm to 90mm in size. These throttle bodies work very well on 5.0L and 5.8L EFI engines with multi-port induction. They work quite well atop a single-plane manifold as well.
Easy To Understand EFI
Ed is using the Speed-Pro SFIMS from Federal Mogul Performance. It is simple and easy to understand, but it's not something you can trot right down the local speed shop and buy in kit form--at least not the way Ed has configured it here. It must be pieced together using all the parts we're about to show you. Once we arm you with all the necessary information you're going to need, you will find yourself wanting this system badly enough to give it a try. Most of it is as near as your local Federal-Mogul Performance dealer. Worthington teaches us that we have to rethink our "thinking" about engine tuning and performance. Start by tossing your carburetor because restomod is headed more toward EFI in the years ahead. "Too complex!" you say? Tell you what--EFI is actually more simple than your four-throat carb. It's more efficient and cleaner burning, plus it yields greater fuel economy--even in a huge Galaxie or Turnpike Cruiser.
Think of electronic fuel injection as your engine's performance management system, monitoring every aspect and adjusting fuel delivery and spark timing perfectly based on the engine's needs. It does everything (and more!) your old point-triggered distributor and fuel-bowl carburetor ever did, only faster, cleaner, and more precisely. We tend to think of EFI on today's cars as a highly complex system--too complex for the average person to understand. A carburetor is, in fact, more complex than EFI. And a carburetor is far more challenging to troubleshoot because it is more unpredictable--core shift, plugged passages, stuck needles and seats, and all important jetting. Jet your carb for sea-level use and you will be disappointed when it's time to head for the mountains. Head for the mountains with EFI and your engine will automatically adjust for the thin, high elevation atmospheric pressure.
What makes Speed Pro's system different from Ford's EEC-IV SEFI or GM's TPI/TBI is the tunability of each cylinder. With Ford and GM electronics, you tune the engine as a package. With Speed Pro's SFIMS, you tune each bore as if it was a individual engine--eight one-cylinder engines hammering out a smooth, consistent beat on a common crankshaft. Ed does this with a laptop computer, using Federal-Mogul Performance's C-Com software on a PC-based laptop (IBM 386 and higher). This system allows Ed to take full advantage of performance cams, nitrous systems, superchargers, and any other mechanical upgrades.
Why tune each cylinder? The answer is simple. It's no mystery to most of us that no engine is perfect. No matter how perfectly you machine the surfaces and size the chambers, there are going to be inconsistencies from cylinder to cylinder and from bank to bank. No two combustion chambers are exactly the same size. No two pistons seal exactly the same way. No two rods are exactly the same length. No two bores will yield the same compression. And no two intake runners follow exactly the same path. All of these inconsistencies conspire to make for uneven cylinder performance, even with a blueprinted engine. With Speed Pro's SFIMS, you can tune the spark and fuel curve on each cylinder. If we need a broader pulse width (more fuel) on a particular cylinder, we can dial in a richer delivery with the laptop. Perhaps there's not enough spark advance on cylinders #1 and #8. We can dial in more timing. And we can do this even as we drive. What this means for performance is more of it. Dialing in each cylinder on the laptop enables us to enhance performance like never before.
While Ed was explaining this system to us, he gave us a sneak peek at the future. Cylinder tunability hasn't been taken to the max yet. We will soon witness O2 sensors positioned at each exhaust port for the most optimum engine tuning package ever. This concept is right up there with "coil-on-plug" ignition found on Ford's new 4.6L V-8s. With an O2 sensor on each exhaust port, this will enable enthusiasts to custom tune each cylinder even more effectively than ever before for improved torque, cleaner emissions, and greater fuel economy. Where Ed's concept differs from Federal-Mogul's is in his use of a mix of GM and Ford sensors. He has opted for the use of GM MAP (manifold air pressure) and air volume (just like Ford's mass air sensor) sensors. The air idle control and fuel pressure regulator are also GM. Ed went to the Ford parts bin for the throttle position (TPS) and water temperature sensors.
Federal-Mogul provided the electric fuel pump, ECM, and main harness. You can simplify your efforts by using the complete Speed Pro SFIMS system, which includes the ECM (Speed Pro calls it the ECU, for electronic control unit), main wiring harness, injector wiring harness, five-foot communication cable (for use with the laptop), and C-Com software (for tuning purposes). To complete the system, you're going to need the injectors, bungs, O2 sensors, coolant temperature sensor, MAP sensor, throttle position sensor, air temperature sensor, idle air control motor, fuel rails, fuel pressure regulator, fuel pump, single-plane intake manifold, and a throttle body setup.