EZ-EFI Fuel Injection System - Super Chevy Magazine

Ez Efi Fuel Injection System Installed Throttle

Most of us with classic Chevys strive to upgrade our rides for the street. We ditch drum brakes for discs, bolt in overdrive transmissions, add air conditioning, and perform a plethora of other upgrades with one goal in mind: better street manners. We've gotten used to modern cars and while we still dig the timeless lines and "soul" of our older cars, we also appreciate the technological advances of the last 40 years. One of the biggest advances in terms of drivability is electronic fuel injection, more commonly referred to as EFI.

Until recently, the only downside to slapping an EFI system into a classic Chevy was complexity, and to some degree, cost. Typically, the intake manifold had to be modified to accept fuel injectors or outright replaced. The tuning systems were complicated and either required a laptop or "one size fits most" programming. FAST saw an opening in the market for a simple to install kit and developed its EZ-EFI system. Unlike its more robust systems, like the XFI line, EZ-EFI is geared towards the "average Joe" who is more concerned with making his ride nicer to drive on the street and cruise down the highway than building a racecar.

Ez Efi Fuel Injection System Baseline Engine

Here's our baseline engine, a 454 big-block with RHS heads and a middle-of-the-road camshaft. It's one of Westech Performance's test mules so it was perfect for this exercise. Normally it makes less than 550 hp, well under the EZ-EFI's performance ceiling.

Here's our baseline engine, a 454 big-block with RHS heads and a middle-of-the-road camsha

To get the price and complexity down, the EZ-EFI system was designed to use an existing 4150-style intake manifold. The four fuel injectors are integrated into the throttle body so there's no need to buy a new intake or modify an existing one. In fact you can even use your current carb-style air cleaner. The downside to this is that with only four fuel injectors the EZ-EFI isn't really suited for engines that put out over 550 hp. Then again, contrary to what you may read on the internet, the vast majority of cars out there make under 500 ponies.

There are several features built into the EZ-EFI system to improve drivability. The key one is what FAST calls "adaptive learning." This in essence lets the system tune itself and anyone who has messed with a more complicated EFI system can certainly see the benefits. The system also has a "pre-squirt" feature that helps starting by injecting a small amount of fuel into the manifold at key-on. We found the result of this to be that our big-block fired up at the push of a button, just like a modern LS engine.

Ez Efi Fuel Injection System Throttle Body

Here's the main player in the FAST EZ-EFI kit, the throttle body. One key to it carrying the "EZ" moniker is that the four fuel injectors and most of the sensors are all integrated into the throttle body. It's also compatible with any standard carb-style air cleaner, so you can keep that "old school" look.

Here's the main player in the FAST EZ-EFI kit, the throttle body. One key to it carrying t

So, what this new system is all about is drivability and ease of install. To put the EZ-EFI to the test we decided to find a carbureted engine and see how easy it was to put on the FAST system and get it running good. Doing this on an engine dyno would give us better control and allow us see what the real world results would be. After all, the "butt-o-meter" is only so accurate.

On the back of the throttle body is the Idle air control motor along with two of the fuel injectors. The base of the throttle body also houses three manifold vacuum ports, and there's one ported vacuum port on the body near the air temperature sensor. FAST really worked hard to make the unit as compact and unobtrusive as possible.
On the back of the throttle body is the Idle air control motor along with two of the fuel
Since the throttle body is designed to replace any carburetor that works on a 4150 square-flange manifold, it was a no brainer for FAST to make the unit accept any Holley-style throttle linkage. Just like a carb, you'll want to make sure to use a throttle return spring or two. Also, just below the braided crossover fuel line is the TPS idle re-calibration screw.
Since the throttle body is designed to replace any carburetor that works on a 4150 square-
On the passenger side of the unit, there's the air temp sensor and the throttle position sensor.
On the passenger side of the unit, there's the air temp sensor and the throttle position s

Ez Efi Fuel Injection System Graph Chart

Purely out of curiosity, we decided to also try a bigger carb on the engine. In this case the 1,000 cfm Holley HP that was on the engine when we bolted it to the dyno. It put down 531 lbs-ft at 3,900 rpm and 516 hp at 5,600 rpm. About the same torque as the EFI system, but 20 more peak horsepower. The down side would be that the 1,000 cfm carb sucks fuel like it's going out of style compared to the EZ-EFI.

There's also a chance that over time, with more WOT "driving," the adaptive learning function would further fine tune the EFI system and raise our peak numbers a bit, but most likely not up to the numbers put down by the monster Holley carb. But for a street car that spends most of its life under 5,000 rpm, the EZ-EFI system offers performance on par with a traditional carb with drivability that the carburetor can't come close to. Best of all, it really was easy to install.

Meet the brains of the system, the ECU. When connected to the wiring harness, the ECU is water tight and can be mounted just about anywhere. FAST recommends that the ECU be mounted at least a couple of feet away from any "noisy" components such as ignition boxes, coils, or distributors. There's also a red LED near the logo that will flash if the ECU detects a problem.
Meet the brains of the system, the ECU. When connected to the wiring harness, the ECU is w
Also included in the kit is a wideband oxygen sensor and a bung for the exhaust system. The fitting needs to be welded, but if you can't do it yourself any competent exhaust shop can install it for few bucks. Run the supplied plug in the hole until you have the system installed and not the sensor itself. Running the O2 sensor without it being connected will shorten its life due to deposits building up.
Also included in the kit is a wideband oxygen sensor and a bung for the exhaust system. Th
The wiring harness may look like a bowl of spaghetti, but it's surprisingly easy to install. One reason for this is that all the connectors are clearly labeled, and FAST includes several wiring diagrams to make installation a snap.
The wiring harness may look like a bowl of spaghetti, but it's surprisingly easy to instal

One sensor not integrated into the throttle body is the coolant temperature sensor. It can go just about anywhere, but we chose to mount it in the intake manifold using the supplied adapter.
One sensor not integrated into the throttle body is the coolant temperature sensor. It can
And with that, the system was installed and we were ready to fire up the 454 to start the calibration process. In regards to fuel our Superflow 902 dyno already has an EFI-ready system. If you're converting from a carb you will need an electric pump and regulator capable of putting out 43 psi. To make things easier, FAST does offer a fuel pump and a line kit just for the EZ-EFI system.
And with that, the system was installed and we were ready to fire up the 454 to start the
Set up and tuning of the EZ-EFI is done through this handheld interface. It has a straightforward menu system that we found very easy to navigate. In addition to setting up the system, it also serves as a scan tool that displays live data and diagnostic information.
Set up and tuning of the EZ-EFI is done through this handheld interface. It has a straight

The first step was to fire up the engine and let it warm up to the target temperature of 140-plus degrees. During this process we adjusted the throttle to maintain idle. We also had to input the engine size, fuel pressure, and a few other pieces of information. This was all done in a step-by-step process using the menu's "setup wizard" function. The main menu also tracks live data, reads error codes, and let us perform advanced functions.
The first step was to fire up the engine and let it warm up to the target temperature of 1
Under the Advanced Options screen, we set our target idle speed, rev limiter and put in our air/fuel ratio targets. The rev limiter works by disabling the fuel injectors until the rpm drops to a safe level. According to FAST, this can also be used as a form of "valet mode" since it's easy to temporarily lower the RPM level.
Under the Advanced Options screen, we set our target idle speed, rev limiter and put in ou
In our application, the guys at Westech went with 14:1 at idle, 13.8:1 at cruise, and 12.8:1 at wide open throttle (WOT). During the course of the day, these were adjusted a bit since it takes a bit of experimenting to find just the right setting. For example, when cruising a leaner target (higher number) will use less fuel and increase mileage- just remember not to let the system go too lean.
In our application, the guys at Westech went with 14:1 at idle, 13.8:1 at cruise, and 12.8

The key to the FAST EZ-EFI system is its adaptive learning feature. This system goes beyond normal closed loop fuel control. In essence it tunes itself by using oxygen sensor feedback to adjust the underlying base fuel table as well as the instantaneous fueling. This way the closed loop system only has to make fine adjustments. We found that the system took a while to learn and the more we ran the engine the better it did. If installed in a car the best tactic would be to get the engine idling nicely and then drive around for an hour or so.
The key to the FAST EZ-EFI system is its adaptive learning feature. This system goes beyon
We decided to make our first baseline pulls using a 750 cfm Holley carb. Given that the EZ-EFI system is rated up to 550 hp, this seemed like a likely carb size it would replace. The best pull we got with the carb was 526 lb-ft at 3,900 rpm and 504 hp at 5,700.
We decided to make our first baseline pulls using a 750 cfm Holley carb. Given that the EZ
Here, you can see one of our better EFI pulls compared to the earlier carb numbers. The FAST system made 532 lb-ft at 3,800 rpm and 496 hp at 5,600 rpm. In essence, it lost eight peak horsepower to the carb, but made an additional 6 pounds of twist. I guess we would call that a draw between the two. Where the EFI system excels is in terms of drivability. Where we had to crank to start the engine with the carb the same engine with the EFI system started with a push of a button.
Here, you can see one of our better EFI pulls compared to the earlier carb numbers. The FA

SOURCES
Westech Performance Group 11098 Venture Drive Unit C Mira Loma CA 91752 951-685-4767 www.westechperformance.com	FAST (Fuel Air Spark Technology) 3400 Democrat Road Memphis TN 38118 877-344-8355 www.fuelairspark.com