Self-tuning EFI systems have been all the rage in the past few years, thanks to the many refinements made in these kits. The new crop of EFI conversions give us much better control of the functions that most people can easily understand – like air/fuel ratio, rev limit, and basic engine functions and parameters.
In years past, you needed to hook up your computer because you need to understand things like fuel curves, injector pulse width, flow rates, and be able to read fuel delivery tables; it seems you also have to have a degree in computer science. Those details have kept many people far away from converting their musclecar over to fuel injection.
But the refinements that we’ve seen lately, like those found in Edelbrock’s E-Street Fuel Injection self-tuning systems, have made the conversion a much more user-friendly process, and you now have all the controls you need at your fingertips. If you’ve thought about pitching the carburetor and giving your classic car improved drivability, the E-Street EFI is a kit you’ll want to consider.
Designed to be a simple installation that will make your car run smoother, start better, and be more fuel efficient, the E-Street EFI is a self-learning fuel injection system that begins to learn as soon as you start the car. No more grabbing a screwdriver and popping the hood to turn an adjustment screw, or fixing the choke.
Some of the latest technology is built right into the kit: wireless communication, a seven-inch tablet with touchscreen, and the ability to update your software through internet download. You can even download some of your favorite tunes on the tablet, and connect to an audio device. The E-Street EFI puts you in control, while it learns about your car based on your input.
The Vehicle: 1967 Chevrolet Corvette
For our installation, we reached out to our friend Adam Miles to install the E-Street EFI on his ’67 Corvette. The car has been modified and updated with a ZZ4 Chevrolet crate 350 backed by a 5-speed overdrive transmission. “The car was built to be a daily driver, so it had to be fun to drive but also couldn’t be a pain to maneuver around in traffic,” shared Miles.
When we first brought the car into the shop, the first thing we noticed was that it ran extremely well, it had some power, but it also had decent road manners and it certainly didn’t disappoint. We pulled it onto our Dynojet dynamometer for some base numbers, to see what our starting point was with regards to horsepower, torque, and air/fuel ratio (AFR).
Putting down 287.36 RWHP and 331.95 lb/ft of torque, with an AFR right where it should be at about 12:1; we had some great base numbers for a regularly driven musclecar. But can this E-Street EFI kit improve upon those numbers, and at the same time give us better fuel economy and drivability? That’s what we’re here to find out, so follow along as we take you through this installation.
Fuel System Choices
With any EFI system, you must up the ante when it comes to fuel pressure. The best fuel pump for a carburetor isn’t going to provide the necessary psi for a set of fuel injectors. Edelbrock offers up three choices for the E-Street EFI: a return-style, a returnless-style, and a universal fuel sump system in both 49 psi and 60 psi. The return-style fuel system requires a return line to the fuel tank, while a returnless-style does not; both systems require an electric fuel pump, either in-tank or inline. The system we selected for this install is the sump style, which uses a sump tank to store the fuel, with an electric fuel pump inside the sump tank.
How does the sump tank work? It’s a pretty cool setup, because you retain your original fuel pump for the carburetor and use it as a lift-pump for the sump tank. The low pressure fuel pump delivers the necessary fuel to the sump tank, where the electric pump provides the necessary fuel pressure to fuel the injectors.
Although the mechanical pump only delivers up to nine psi, it still delivers the fuel flow necessary to feed the system. Fuel pressure is not the same as fuel volume; the E-Street EFI will support up to 600 horsepower, and both the mechanical pump and the EFI pump will deliver the volume necessary. Since the injectors need pressurized fuel for the throttlebody, the EFI pump delivers the necessary fuel pressure from fuel stored in the sump tank.
Like the returnless-style fuel system, the sump tank set up eliminates the need to run a return line back to the fuel tank. Classic cars typically don’t have provisions for a return line, but with the sump kit we were able to confine all of our installation to the engine compartment using existing fuel lines as our starting point for fuel delivery.
Mark Honsowetz, Electronics Engineer at Edelbrock, says, “One of the big problems with EFI conversions is fuel slosh. Our sump tank stores about a gallon of fuel and even if the mechanical pump is pulling air from hard cornering, the sump tank keeps the pump pressurized.” That sump tank was designed to eliminate fuel slosh issues, and Honsowetz says it’s available separately for those who want to add it to their existing EFI conversion.
Proper Planning Saves Time
Like any major job, proper planning is necessary to not only save time, but also to save headaches down the road. If you go into any major task without planning, you run into the risk of having to make changes that you weren’t prepared for, and that can cost you time and money.
The first thing we did with our E-Street EFI is to read the instructions thoroughly. Our tech for this install, Sean Goude, has installed nearly every EFI system on the market in our shop, but since this is a new system, he still broke out the instruction manual and read through it to get a full understanding of what needed to be done prior to bringing the car into the shop. There are two additional components that need to be mounted in the engine compartment: the ECU, and the sump tank.
The sump tank isn’t a huge component, but it does require some space, primarily depth, within the engine compartment. We needed to find a suitable location where it wouldn’t interfere with other components, and also where it would be far enough away from high temps – like the exhaust headers. Although the ’67 Vette has a pretty cramped engine compartment, we found plenty of room in the area between the firewall and the wheelhouse on the driver’s side. One down, one to go.
The ECU is the brains of the EFI system, and while it’s smaller than the sump tank, we also needed to find a suitable location for it. The ECU can be mounted in the interior of the car, or in the engine compartment, either place is acceptable providing it isn’t too close to a major source of heat, and it also needs to be protected from the elements to some extent. The perfect spot for this installation was on the opposite side from the sump tank, and we decided the best location was to mount it on the wheel house on the passenger’s side, above the battery.
Since the ECU and the included 7-inch touch screen tablet share a wireless connection, we didn’t need to run any cables through the firewall and into the interior of the car. If we had decided to run the ECU into the interior, a suitable spot on the firewall would have been planned out so we could mount the box and be sure to seal up the wires. Once the ECU is mounted and the cable attached, we won’t need to access it again – there are no LED lights or indicators on the box, so the location we chose suits our needs perfectly.
The E-Street EFI Installation
Once we established our mounting locations for the ancillary components to the throttle body, we were ready for installation and brought the car into the shop the following day. We were up against some pretty impressive numbers to begin with, but we knew that the EFI would enhance the driving experience in ways that tuning a carburetor can’t. An EFI system will make adjustments for whatever atmospheric conditions and temperatures are read, and also based on readings that the included wideband O2 sensor sends back to the ECU.
A narrow band sensor, typically a one or two wire sensor, simply sends the AFR reading to the computer. Wideband O2 sensors, typically five or six wire sensors, reads the AFR, and also measures other parameters, like back pressure, and exhaust and operating temperatures. This data is used to communicate with the computer to make adjustments based on the conditions in the exhaust. This wideband sensor, as you might guess, needs to be mounted in the exhaust system as close to the collector as possible to get an accurate reading.
Included with the O2 sensor is a weld-on bung that must be welded onto the exhaust pipe. If you aren’t able to weld it on yourself, you can easily take the car to an exhaust shop, have them drill the hole and weld the bung in place for you. There is an included plug that allows you to cap off the bung and drive your car back home until you’re ready to install the EFI. The O2 sensor must face upwards, so it requires room for the sensor and wiring. We located a spot that gave us plenty of room to keep the wires away from the rest of the exhaust header and other heat sources.
With our plans already laid out, and the exhaust bung welded into place, the rest of the installation went by without a hitch. We marked holes for drilling on both wheelhouses to mount the sump kit and the ECU. The sump kit includes a pair of brackets that get mounted to the tank, and those brackets bolt to the mounting location.
The sump tank has a check valve in it, so the pump needs to be vertical, of course. A slight angle won’t affect its functionality, but it does need to be as close to vertical as possible.
The sump tank has four fittings on the top: one for the electrical connection for the pump, a fuel inlet and outlet, and a breather. The breather vents vapors from the tank, so an included hose must be used to route those vapors to the outside of the car. We ran the hose down below the body of the car and out from under the engine compartment.
The ECU, as we mentioned, was mounted to the other side of the engine compartment, keeping in mind that we have to be able to access the plug so that we can connect the main harness to it. We marked the holes for drilling and mounted the ECU with the provided screws.
The ECU can be mounted in just about any position, but it’s recommended that the plug does not face upward so that if any moisture reaches the plug it won’t pool up inside. This could cause problems with the connection or the terminals.
The carburetor on this Corvette was removed, and the throttle body put in its place. We made sure to pay attention to how our throttle lever was connected, and since this throttle body has the standard lever, like most carburetors do, it was simple to reconnect the throttle lever.
If you’re using a cable, and a kick-down for an automatic transmission, be sure to note how they are connected. Reconnecting them will be just like replacing the carburetor with another one, but having the proper tension on the kick-down means that you may have to make an adjustment.
The throttle body will bolt onto most square-bore, 4150-style flange intake manifolds designed for a carburetor, and it’s roughly the same dimensions as an Edelbrock carburetor. You should be able to reuse your air cleaner, and we reused ours, even though it had a dropped base. The only adjustment we needed to make was to aim the fuel line downward to clear the base of the air filter. Other than that, we installed a new stud kit for the center of the air cleaner and it was good to go.
The throttle body contains all of the sensors needed, with the exception of the coolant temperature sensor. The throttle position sensor, the fuel injectors, the idle air control valve, air temp sensor and the fuel rails are on the throttle body itself. The main harness will plug directly into all of the sensors with pre-terminated connectors for a professional installation. We also laid out the harness to make sure that we could plug all connectors into the throttle body. The additional coolant temp sensor is mounted to the intake manifold, and this provides the coolant temperature reading for the ECU to function.
We connected the throttle linkage and then addressed the fuel lines prior to running the wire harness to all of the connectors. Since our sump tank is higher than the fuel tank, a pump is needed to ‘lift’ the fuel to the tank. The Edelbrock mechanical fuel pump on the engine works just fine, and we installed an inline filter after the pump, and then ran the fuel hose directly to the sump tank, using the included -6 AN fitting. Another AN fitting was used to connect the sump tank fuel line to the throttlebody.
Since we installed our sump tank on the driver’s side, we didn’t want to run the fuel line all the way around the engine compartment, so we flipped the fuel rails around in order to have the fuel inlet facing the sump tank. This does not cause any problems with the installation or fuel delivery, and we simply removed a couple of screws from each side and reversed the fuel rails, leaving the injectors in place. A second, 10 micron fuel filter, was installed in line with the fuel inlet. This is necessary to filter out anything that may have gotten past the 40 micron filter that we installed.
Making All The Right Connections
With our three major components installed, the wiring harness was laid out and installed. We have a little bit of a stealth thing going here with the sump tank and ECU somewhat hidden from view, so we opted to continue that theme and route the harness against the firewall.
The connections are rather simple: the hot and ground wires connect directly to the battery; the tach input signal connects to the coil; and the remaining harness plugs into all of the senders and sensors, injectors, and fuel pump. We made sure that all wires were kept away from moving parts, and also away from any direct source of heat. The harness has convoluted tubing to protect it, so laying across an intake manifold is acceptable, but be sure to keep it far enough away from the exhaust.
The harness installed easily; all of the connectors have enough length to plug into their respected terminals, and since we mounted the ECU above the battery we were able to cut down the length of wire. There is plenty of wire if your connection isn’t as close to the battery as ours, and it can be extended for trunk mounted batteries, but the hot and ground wires need to be mounted directly to the battery, and not through any other source of power in the car. For safety, a 20-amp inline fuse can be used for remote battery connections, as a precaution.
Setting Up The Tablet
We finished the physical installation of the E-Street EFI in about a day, and we were very impressed with the overall kit and how everything came together. The next, and final connection was wireless: we turned the key on, fired up the 7-inch touch screen tablet and waited for our wireless connection to be established. Having this wireless tablet allows us to make our initial settings and adjustments from anywhere in or around the car. The elimination of a cable also keeps us from having to drill a hole through the firewall for using the tablet inside the vehicle.
The tablet was one of the coolest parts of the installation. Once we established our connection, we were given full instructions on how to set up the EFI system. The software is pre-loaded, and a computer connection is not necessary in order to set up the EFI.
Honsowetz said, “We’re working on a method for sending update information to customers, for now they can simply check the Edelbrock web site and download updates directly to the tablet.”
Self-Learning Through Development
We found a very useful video on Edelbrock’s web site that shows the functions of the tablet. The instructions start off with questions you answer about your car: engine size, rev limit, cam size, and you can even set parameters for things like AFR and when to switch on an electric cooling fan.
We created and tested every base map in the tablet extensively, there is no extrapolated information used for those base profiles. -Mark Honsowetz, Electronic Engineer
But it doesn’t stop there, because this EFI system is self-learning; it is constantly monitoring the engine’s parameters and making adjustments as you run the engine, and as you drive. If the idle appears rough at first, it’s because the system needs to establish a baseline reading and then make its adjustments accordingly.
Honsowetz said, “We created and tested every base map in the tablet extensively, there is no extrapolated information used for those base profiles. We resolved all known issues with EFI conversions through continued R&D; the base maps are very well developed and designed so that the system works right out of the box.”
We asked if there would be an added feature later for storing profiles and he told us, “The E-Street EFI learns so quickly and so well that we really didn’t see any need for storing different profiles. You can simply make a change to the parameters if you want to tune for better economy, but for those who are hard on the throttle the computer makes adjustments very quickly.”
The idle will smooth out, and the adjustments will be made as the ECU learns about your engine and the fuel delivery – all with the help of the wideband O2 sensor we installed in the exhaust. The tablet can be mounted to the windshield via the included mounting kit, or somewhere on the dash or console, if you prefer. It can also be kept in the glove box, because you don’t need to have the tablet powered up while driving the car.
You use the tablet for initial settings or later adjustments, or you can use it to download some of your favorite tunes and connect it to an audio device. This full color, full feature wireless tablet will become your best friend in no time because it’s very user-friendly and will even provide a real-time display of your engine’s functions, like a tachometer, temperature gauge, fuel pressure, AFR, throttle position, and more.
The Bottom Line – Performance And Drivability
After we drove the car around a little bit to let the computer do its learning and make the necessary adjustments, we were eager to get the car back on the dyno and see what kind of numbers we could get. With most EFI conversions, you can almost expect to lose a horsepower or two as a trade off for efficiency and drivablity. For serious horsepower achievements, there’s no match for a finely tuned carburetor on a high horsepower build, but for drivability, fuel economy and control over things like AFR and throttle response, not much can beat an EFI conversion.
We put the Vette back on the rollers and fired it up, and ran it through the gears. The first run brought us an improvement, but we saw a little blip on the screen – the computer was still learning since that was the first time we brought the engine revs up that high. We ran it again to see if that little blip would disappear, and to see if our numbers would be consistent.
The second run after the installation of the E-Street EFI netted us 310.22 RWHP and 357.82 lb/ft of torque, for an increase of 22.86 RWHP and 25.87 lb/ft of torque over our initial run with the carburetor. That little blip? It was gone, showing us that the computer learned, on its own, and took care of what it needed to do to make adjustments, proving to us that it truly is a self-learning system.
As soon as Adam Miles got into the Vette and started it up, he knew right away that it was not just different, but better. It started better, and idles smoother, and it even sounded different. As the owner of several musclecars from the ’60s through the ’70s, he’s no stranger to performance, but does admit that the Corvette is his favorite – and we can see why. Now he has another reason to love driving this car, because the old ways of the carburetor are no longer, and a self-learning EFI system is going to keep that 350 running smoother. We’ve heard back from Miles that his fuel mileage has increased on longer trips with the ‘Vette. Prior to installation, he got a respectable 17 MPG, after a week of driving, breaking it in, and taking it on a trip, he’s pushing 22 MPG. And that makes cruising on E-Street even better than it was before.
To find out more about the E-Street EFI and what’s available for your classic car or truck, be sure to visit the Edelbrock web site and get the latest in performance and technology.