F.A.S.T. EZ EFI Kit Install - EFI: It’s Not Just For Your Minivan Anymore
We found a kit that is truly plug-and-play and made for your Muscle car
From the December, 2011 issue of Mopar Muscle
By Randy Bolig
Photography by Darren Tedder
When it comes to the local soccer mom and her minivan, she doesn't care whether or not that engine is carbureted or fuel injected. All she cares about is whether or not it'll start and get her to the appropriate location to drop off the kids and have a couple hours of peace and quiet-she'll think about picking them up later-maybe. For years, carburetion was the mainstay of every car's fuel delivery system, and it worked relatively well. That is, until the needle for the float stuck, the carburetor needed a rebuild, or some enterprising hot rodder thought he knew what he was doing, and adjusted it.
It was in the mid-'80s when EFI started to become prevalent on new cars. Sure, there were some car manufacturers that tried a couple of different types of EFI in the '50s and '60s, but it wasn't until the mid-'80s when it really became a mainstay from the manufacturers. Those early EFI setups were new for the times, and more than capable to make any mechanic pull out his hair while troubleshooting an issue. And in the eyes of many hot rodders, some things never change.
Why did the auto manufacturers arbitrarily switch to EFI? Was it a better mousetrap? Was it cheaper? Or did they do it to simply keep the average guy from doing repairs himself, and have to take the car to the dealership for repairs? Whatever you think the reason is, EFI is here to stay, and it's even making the move within the aftermarket for us muscle car guys to adapt to our cars. But what is fuel injection, and how does it work?
What's the Difference?
The primary difference between a carburetor and fuel injection is that fuel injection atomizes the fuel by pushing it (under high pressure), through a nozzle. A carburetor relies on a low pressure signal, or vacuum created by intake air rushing through it to add the fuel to the airstream. Fuel injection generally increases an engine's fuel efficiency by improved cylinder-to-cylinder fuel distribution. In other words, since the fuel is more evenly distributed, less fuel is needed for the same power output. When cylinder-to-cylinder distribution is less than ideal, as with a carburetor, some cylinders usually get an excess of fuel. This is a side effect of making sure that all cylinders receive at least the minimally required amount of fuel. Extreme distribution problems will, if not immediately, eventually begin to reduce efficiency. Overly extreme distribution issues substantially affect power. By optimizing the uniformity of cylinder-to-cylinder fuel-mixture distribution, all of the cylinders reach their maximum power potential, and the engine's overall power output improves.
There are different types of electronic fuel injection systems found in automobiles and other vehicles, and we'll briefly explain them here.
Throttle Body Injection (TBI)
This is possibly the simplest type of fuel injection. A device that resembles a carburetor's "body," is fitted with fuel injection nozzles, and simply replaces the carburetor. For some automakers, TBI injection was the beginning of the more complex multi-point systems that followed. Although the TBI injection system may not be as precise as some of the EFI systems that have followed, TBI meters fuel better than a carburetor, are less expensive, and are easier to service.
Port or Multi-Point Fuel Injection (MPFI)
Multi-point fuel injection means that there is a separate injector nozzle for each of the engine's cylinders. Each injector is located directly outside of an intake port. This is why the system is occasionally referred to as port injection. With the injector spraying the fuel vapor this close to the intake port, it ensures that it will be drawn completely into the engine's cylinder. MPFI has the capability to meter fuel more precisely than TBI design.
Sequential Fuel Injection (SFI)
Sequential fuel injection, also called sequential port fuel injection (SPFI) is a type of multi-port injection. This does not mean that it's the same as MPFI. A basic Multi-Port injection employs multiple injectors, as does Sequential Fuel, but the Multi-Port injectors all spray their fuel at the same time or in groups. As a result, the fuel may pool, or puddle, in an intake port for as long as 150 milliseconds when the engine is idling. Sequential fuel injection triggers each injector nozzle independently. With Sequential injection, the injectors are timed like spark plugs, and they spray the fuel immediately before, or as the intake valve in their respective cylinder opens.
Direct injection is the most complex and takes the concept of fuel injection about as far as it can go. Direct injection means that the injectors are injecting fuel directly into the combustion chambers, past the valves. While this type of injection was most prevalent in diesel engines for many years, direct injection is starting to make an appearance in gasoline-engine designs. When referring to this type of injection in regards to gasoline power, it's sometimes called DIG for direct injection gasoline. Again, fuel metering is even more precise than in the other injection systems, and Direct Injection gives engineers yet another variable to influence precisely how the combustion occurs in the engine's cylinders.
It's All About the Parts
When it comes to fuel injection, choosing the right engine parts that have to work with the injection system is just as important as it is for choosing them with a carbureted engine. We asked Darren Tedder of Prism Racing in Conyers, Georgia, how important camshaft selection is to an EFI engine. According to him, running a cam with larger than average lift and duration numbers is actually easier to do with EFI than it is a carburetor. With a carburetor, you have to find a balance between wide-open throttle, cruising speed, and idle. Tuning for one aspect is easy, but your setting for one situation can-and usually does-have an adverse affect on the others. For instance, getting an engine that has a camshaft with a large duration number to idle, means raising the idle setting, which in turn opens the venturi butterflies more, which in turn pulls more fuel because of the increased air flow drawn over the idle and transition circuits. Like we said, tuning a carburetor requires concessions with at least one aspect of the fuel curve.
On the other hand, tuning an EFI-equipped engine allows you to infinitely tune the fuel curve. Again, say you have an engine with large camshaft duration and lift, with EFI, you can fine tune the idle mixture, cruise mixture, and wide open throttle mixture simply by telling the injectors to open for a longer or shorter period of time, at any give rpm. Another thing to keep in mind is that EFI is not as affected by a vacuum signal as a carburetor is. When using a carburetor, vacuum from the engine draws fuel into the intake. With EFI, it is squirted under pressure. Since that's the case, unless you're running power brakes, a large amount of vacuum is not required.
When considering an intake manifold for an EFI engine, the same principles apply as if choosing an intake for your carbureted engine. Dual-plane intake manifolds are named for their split plenum opening (where the carburetor mounts). Each side of the opening feeds four cylinders of a V-8 engine. Dual-plane intake manifolds are the most popular for performance street engines, because they generally build power across a wider rpm range, and start making their power at a lower rpm-typically around 1,500. Single plane intake manifolds are aptly named, because they have one large ôhole,ö or opening in the plenum where the carburetor mounts. Fuel from the carburetor/throttle body enters the intake into a single plenum through the single opening with no separation between the right and left side. That single opening feeds all eight cylinders on a V-8. Single plane intakes are typically less restrictive and work best to build power between 3,000 and 8,000 rpm. Because of the higher rpm range capabilities, the single plane intake manifold is best suited for racing applications.
OK, enough with the lesson. How does EFI get retrofitted into a muscle car, and which one should you use? The choice comes down to installing what you're comfortable with. If you're comfortable designing and installing a complete Multi-Port system, go for it. There are manufacturers that have intakes and complete kits available to do just that. The tunability and other benefits of such a system are great for the guy that has a firm grasp of tuning EFI. But what if you like the attributes that EFI has to offer, but you're not a guy that has spent a lot of time tuning and installing EFI kits? There are a couple of kits out there that claim they are bolt-on, and we decided to test one and see just how easy it really is.
For our testing, we have heard nothing but good things about the FAST EZ EFI, and we wanted to see if those praises are warranted. According to the guys at FAST, you don't need a laptop or EFI tuning experience; the EZ module handles that for you.
In the past, a carburetor-to-EFI conversion usually resulted in a nightmare of issues like not enough fuel pressure, and tuning. The guys at FAST tell us that with their EZ kit, you simply hook it up, answer the basic setup questions on the included hand-held display, and the system tunes itself while you drive!
The EZ-EFI system provides you with the complete EFI package, including the ECU, wide-band O2 sensor, wiring harness, fuel injectors, an optional fuel pump kit, and other assorted components, including the 4150-base throttle body. If you're running a, shall we say, more aggressive application, the EZ-EFI dual quad upgrade kit is capable of supporting 1,000-plus horsepower engines with dual quad carburetor-type manifolds.
Regardless of your engine size, this single throttle body system bolts-on to any carbureted engine with up to 600 hp-no manifold replacement is needed. The EZ-EFI system also works with your original carburetor style throttle linkage and is ready to accept all OEM sensors. The guys at FAST tell us that the EZ-EFI can be installed easily in an afternoon.
But we weren't going to make our testing of it easy. We didn't want to bolt this thing onto some restored, stock-engined muscle car and go. Nope, that would be too easy. So, we found a car that would definitely test the limits of the EZ kit. Darren Tedder of Prism Racing in Conyers, Georgia, had a customer with a big-inch Hemi that pushed the limits of what some would call a street car, and we felt this would be the perfect test vehicle. The car is a '71 Road Runner with a big Hemi under the hood. We say big because this Hemi displaces 557 inches via a 4.500-inch crankshaft, 7.100-inch connecting rods, and a 4.440-inch bore. Despite its large displacement, the Hemi features a final compression ratio 10.0:1. The camshaft is a flat-tappet design with 248 degrees of duration at .050 inch, and a 110 LSA. The induction is a Ray Barton intake with an 1150 Dominator. When spinning the lie detector, the carbureted engine made 810 hp. Subtle it ain't.
*Prices we found. You might find better-or not.
|EZ EFI kit||30227||$2,136.95*|
|Dual Quad add-on||304155||$873.95*|
|Stage V intake dual quad intake||$450.00*|
1 Before you even think about...
1 Before you even think about swapping parts, please read the instructions completely. We’re told that the number one reason the tech line gets calls at FAST is because the person didn’t take the time to fully read and understand the instruction manual.
2 A big Hemi with a big camshaft...
2 A big Hemi with a big camshaft and a Dominator carburetor—a tuning nightmare.
3 After reading the instructions,...
3 After reading the instructions, it’s time for the swap. In applications under 600 hp, a single throttle body will deliver all the fuel you need. In our case, there are a few more the 600 horses concealed in the Hemi, so therefore we need to use the dual-quad upgrade kit, which also means changing the intake.
4 There are a couple of choices...
4 There are a couple of choices when looking for an intake, but we went with the Stage V Dual quad unit. Stage V is probably best known for their Wedge to Hemi conversion kits, but they also manufacture high-quality individual parts as well. This intake is a single plane design, and with the way this Hemi is built, it fit our plans perfectly.
5 With the new Stage V intake...
5 With the new Stage V intake installed and the bolts torqued to 40 ft-lb, the throttle bodies are installed next. Tighten the nuts down to 15-inch pounds—just enough to seal them to the intake.
6 As we mentioned earlier,...
6 As we mentioned earlier, our engine is a little over the 600hp rating of the single throttle body kit, so we had to upgrade and add the dual-quad kit.
7a The included wiring harness...
7a The included wiring harness comes complete...
7b ...With labeled ends so...
7b ...With labeled ends so you can easily just plug everything in.
8 The ECU is weather tight...
8 The ECU is weather tight when connected to the harness, so mounting under the hood is an option. If you notice the plastic plug to Ralph’s right, we decided to mount the ECU under the dash and run the wires through the opening after removing the plug. If you decide to mount your ECU under the dash, be sure that the included wire harness will be long enough.
9 After running the wires...
9 After running the wires through any hole in any surface, don’t forget a grommet of some sort.
10a Now you just start.....
10a Now you just start...
10b ...Plugging in conne...
10b ...Plugging in connectors.
11 The coolant temperature...
11 The coolant temperature sensor tells the computer the temperature of the engine so the proper fuel mixture is achieved. When the engine is cold, more fuel is required to keep it running. When it’s warmed up, it doesn’t take as much fuel. How will the ECU know the engine temperature without a sensor?
12 Another sensor that and...
12 Another sensor that and EFI system needs in order to properly function is an O2. The O2 sensor tells the ECU what the fuel mixture is like at any given second so adjustments can be made. In the case of the EZ kit, adjustments are made automatically by the ECU—just like the new car in your driveway. The O2 sensor should be mounted. Installing the sensor just after the collector gives it a good reading from each cylinder.
13 The fuel pressure needs...
13 The fuel pressure needs to be set at 43 pounds, so a vacuum referenced fuel regulator is used. The regulator kit is an option, so you supply your own if you like. The vacuum port needs to be connected to direct manifold vacuum. A vacuum-referenced regulator is used so the proper amount of fuel is delivered under various load conditions.
14 There are two ways to...
14 There are two ways to plumb a fuel system. One is the correct way, and one is the incorrect way. For the purpose of this EFI install, the following is a diagram of the single throttle body design. By using two throttle bodies, you simply add it to the equation directly after the first one.
15 Once you have the regulator...
15 Once you have the regulator mounted, you’ll need to cut your fuel lines to attach it to the throttle bodies. If you’re only using one throttle body, you’ll put a plug in the regulator where we have our second one connected. You’ll also notice that the two return lines from the throttle bodies connect at a Y fitting and then use a single line back to the tank.
16 The electric fuel pump...
16 The electric fuel pump needs to be mounted as close to the fuel tank as possible. Electric pumps work best as pushers, not pullers. The EZ EFI pump comes with a pre-filter incorporated in it, so an external pre-filter is not required. If you are running a different kind of pump, a pre-filter is recommended.
17 Here’s where EFI can cause...
17 Here’s where EFI can cause some concern for some people that are undecided about it. A good EFI kit will not only have a fuel feed-line, but a return line as well. A stock gas tank usually doesn’t have a provision for a return line, but installing a return line can be done a couple of different ways. One is that a rear sump can be added to the tank (Like Ralph’s Road Runner already had), a custom tank can be built, or a factory tank can be modified and fitted for the required line attaching points. We did an Internet search and could only find aftermarket tanks with the pump already installed, so that is another option. In some cases, the factory sending unit might have a port in it that is not connected to anything and can be used for a return. Just be sure that wherever your return line goes into the tank that it isn’t dumping fuel directly on the pickup. This can cause aeration and cavitate the pump.
18 Previously, we mentioned...
18 Previously, we mentioned mounting the ECU under the dash. Once we were sure our wiring would reach, we found a nice place on the firewall.
19 According to the FAST...
19 According to the FAST instructions, the positive and negative wire from the ECU must be connected directly to the battery, not spliced into the radio feed or cigarette lighter. You will experience current issues by taking a short cut. It’s also good insurance to install a breaker inline before the ECU box since it is directly connected to the battery.
20 Although your factory...
20 Although your factory throttle cable connects to the throttle body on a single unit application, since we were using two throttle bodies, we needed to connect them. This linkage comes with the dual-quad upgrade kit. According to the FAST instructions, both throttle bodies should open simultaneously. This allows for the best fuel distribution.
21 It’s an accepted fact...
21 It’s an accepted fact that EFI will not make any substantial power gains over a carbureted setup, but once we had everything installed, we used the chassis dyno to run the car under various load conditions so that the EZ module could “learn” what our engine required under those conditions. We did, however, pick up an additional 10 hp, though that was probably just by virtue of having the extra throttle body, which also meant more air was entering the engine.
22 When it was all said and...
22 When it was all said and done, we asked Darren what his thoughts were about the kit: “I think it’s a well-designed, quality kit. I don’t see any reason why any competent car guy couldn’t install it in a weekend. But, really, read the instructions before you start.”
23 As far as what Ralph thinks,...
23 As far as what Ralph thinks, we couldn’t ask him. We couldn’t ask him because after he drove the car with the EFI installed, he’s driving the car now more than ever.