It’s understandable how doubts and fear could creep into an enthusiast’s mind when swapping the old faithful carburetor in favor of an advanced fuel-distribution system. Before breaking out in a cold sweat, however, consider that the FAST EZ-EFI system can calm any installation panic with a rather straightforward R&R procedure on the engine and a simple programming of the computer that also features self-learning/tuning capability.
Carburetors are good for peak horsepower, but performance-car owners now want drivability, fuel economy and throttle response. That’s where electronic fuel injection is a better choice.
“We usually see an improvement of two or three miles per gallon after the EFI conversion. We had one conversion that gained seven mpg, but that depends on a lot of factors. How well the carburetor was tuned before you make the swap is a big factor,” says FAST engineer Matt Maxwell.
A big advantage of our self-tuning EFI kit is that it was designed in house from scratch.
— Matt Maxwell
The biggest difference between carburetors and fuel injection is the way fuel is introduced to the combustion chamber. Fuel injection atomizes the fuel by pumping it through small nozzles under pressure, while carburetors rely on suction created by air accelerating through a venturi to draw fuel into the airstream.
The carbureted system works effectively but is tuned to a certain rpm and air density. When the air density changes, like driving to a higher elevation, the carburetor’s tuning is disrupted. EFI relies on signals from several different sensors to calculate the precise amount of fuel to deliver for optimal performance in real time, no matter the altitude or air density.
“The EFI system basically has a mini weather station on-board that constantly makes corrections to the fuel mapping based on air density, temperature and such. The ECU is always correcting on the fly, working faster than we can think,” explains Maxwell.
The Test Bed
The project Chevelle is outfitted with a BluePrint 427 LS ProSeries engine, with loads of carbureted power for the street and top-end performance. FAST’s EZ-EFI Self Tuning Fuel Injection System (part #30226-KIT) was chosen to evaluate not only ease of installation but also if an EFI conversion will improve street manners and fuel efficiency.
“A big advantage of our self-tuning EFI kit is that it was designed in-house from scratch,” says Maxwell. “This gives our customers a great level of support, 24-hours a day, 7-days a week, year around. Our tech lines are open from 7 a.m. to 8 p.m., and the community on CPG Nation Forum is well developed. There is no question that can’t be answered quickly. We developed the self-tuning EFI kit with the consumer in mind. In the rare occurrence that a sensor might need to be replaced, we designed our kit to use OE type sensors that are less expensive to replace and are easily found on the shelf of local parts stores.”
Features of FAST’s EZ-EFI:
- Standard single throttle-body system flows 1,100-plus cfm and handles up to 650 horsepower
- Throttle body has 4150-style footprint, works with original carb-style linkage and accepts all OEM sensors
- Complete system includes mini ECU, wide-band O2 sensor, clearly labeled wiring harness, injectors, fuel pump kit and throttle body
- Works with any ignition setup – including HEI
- Easy-to-use Setup Wizard provides a walk-through tuning menu
- Carb replacement, dual-quad, multi-port, 8-stack & Jeep systems available
- Adjustable fuel pressure regulator
- Inline electric EFI fuel pump, 600 HP
- Fuel pressure gauge
- Billet fuel filter (re-usable)
- Relay harness (Plug & Play for EZ-EFI)
- (1) 6AN to 6AN female coupler (filter to fuel pump)
- (2) 6AN to O-ring 6AN straight fitting
- 25-feet push lock fuel hose (#6)
- (3) 6AN push-on straight fittings (Black)
- (2) 6AN push-on 90° fittings (Black)
- (3) Gator clamps
Fuel Pump and Filter Installation
As a believer in using components and kits belonging to the same family, we added the EZ-EFI 600 HP inline fuel pump kit (part #307503) and EZ-EFI fuel pump hose and fitting kit (part #307600) to the project.
FAST recommends mounting the fuel pump as close to the tank as possible and low so that the pump will be gravity fed. All safety precautions dealing with fuel systems apply. Keep the components away from sources of heat and moving parts, confirm that the fuel tank is vented and use the pressure regulator with a vacuum reference port that will raise and lower the fuel pressure with changes in manifold vacuum.
A fuel-pressure gauge is included in the EZ-EFI fuel pump kit, but if you source components elsewhere, an inline fuel gauge is needed to help with the initial set-up.
Baseline for the EZ-EFI system is 43 psi, at which the four injectors and EZ-EFI throttle body will support 550 horsepower. The system will support higher horsepower with higher fuel pressure. The injectors are rated at 88-lbs/hr at 60 psi.
Fuel System Wiring
The fuel-pump-relay harness (included in the EZ-EFI fuel pump kit) consists of three wires: A long red wire feeds power to the fuel pump, a wire with a connector to the main EZ-EFI wire harness and a black ground wire. The entire fuel pump system consists of a cut-to-length power wire and connector for the fuel pump on one end and the relay on the other. From the relay a wire with connector goes to the main EZ-EFI wiring harness with a ground wire at the connector. You simply hook up the two connectors to their intended locations and attach the ground wire.
Fuel Hose and Installation
The FAST EndureX hose and push-on fittings supplied in the EZ-EFI kits are easy to work with in fabricating the fuel lines. We do have one tech tip: Soak the hose ends in boiling water to make them more pliable when installing the fittings.
Like any other fluid transfer system, the hose is cut to length and secured to the push-on fitting by a hose clamp. The fitting is then ready to be attached to the receiving component.
“Our instructions have evolved to the point where we have practically no questions from the enthusiasts doing the work in their garage,” says Maxwell. The FAST EZ-EFI wiring harness is clearly labeled and corresponds to the manual for a smooth hookup to the vehicle’s electrical system.
Positive and negative battery connections must be made directly to the battery or electrical noise could be a problem. A 12-volt connection to a switched source that is hot when the key is in the on/run and start positions will be necessary. The connectors to the injectors, idle motor, throttle, air temp, MAP sensor, coolant temp, O2 sensor and hand-held controller are clearly labeled and sized for the individual component. Connections to the tach/rpm module, fuel-pump relay and controller and air conditioning switch (if applicable) will need to be wired. Large wiring diagrams of the specific systems are included in the instruction manual.
Mounting the ECU
The wiring harness makes a watertight connection when hooked to the ECU, which can be mounted with self-tapping screws in the engine compartment or inside the car’s cockpit. To be on the safe side, FAST recommends mounting the ECU on the inside with the harness connector facing down to reduce the chance of moisture getting into the ECU. When mounting the ECU, keep in mind the length of the wire harness and hand-held controller communication cable. Longer cables are available from FAST, and the hand-held controller is not required to be connected after initial set-up for the engine to run — but thinking through the ECU mounting placement before settling on the “perfect” location can keep all the options open.
The next stage of the EZ-EFI injection system begins under the hood with the throttle body. Disconnecting the throttle linkage and removing the old carburetor should be a snap, then the EZ-EFI throttle body will bolt directly on the intake manifold’s 4150 square-bore flange. The throttle body uses Holley-style throttle linkage, so your existing linkage should mount up easily. FAST includes a ball stud and lock nut to complete the linkage hook up. As with any carburetor or throttle-body installation, a throttle return spring should be used. FAST has built in some adjustability between the throttle shafts so that they can be set close to a 1:1 ratio. Having all four blades open at the same time gives the best fuel distribution. Installing the air cleaner and checking for hood clearance is highly recommended at this point.
The system setup starts with the EZ-EFI hand-held controller.
“It’s actually multiple tools in one. It can act as a code reader or scan tool and even clear error codes, and it can monitor live engine data and make adjustments on-the-fly as you drive,” explains Maxwell.
We checked for error codes, and finding none, moved into the “Setup Wizard” pull-down menu. Users are asked if they want to start a new tune or reset the ECU to the base tune. Selecting to start a new tune will automatically reset the learning feature, rev limiting, air/fuel ratio targets and the engine’s electric-fan operating temperature.
After entering some basic details about the engine into the Setup Wizard, the car was ready to fire up. Immediately the learning procedure began as the ECU fine tuned the fuel map. As we test drove the Chevelle around for driving impressions, the handheld controller showed a 15-to-20 percent correction as it continuously learned on-the-fly.
“It was interesting to feel the throttle smooth out the more that we drove it,” reports our test driver. “On initial start-up, we had to hold the throttle at different targets until the engine got to operating temperature. It was very impressive to see how the self-learning function adapted to the targets like idle rpm.”
The EZ-EFI self learning fuel injection system can be installed with basic maintenance skills and common hands tools. If the installation started on a Saturday morning, by Saturday evening you could be cruising downtown with electronic fuel injection in your classic muscle car… just like we did.