Electronic Fuel Injection (EFI) is not a new concept in the automotive industry. American Motors Corporation (AMC) designed the first commercial EFI system, called the Electrojector. This system was developed by Bendix back in 1957. Since that time, fuel injection has gained popularity as it increases an engine’s efficiency as well as drivability. It’s impossible to find anything but fuel injection on modern cars these days.
Over the years, enthusiasts have figured out ways to utilize factory EFI systems and adapt them over to fit their needs. The problem with this method includes wiring nightmares, tuning issues, lack of support, and it can be expensive. Unless you have the correct software, a computer, and some tuning knowledge, you would need to haul your car to a tuner for some dyno time and a custom tune. While this method works, it’s costly.
Edelbrock is out to fix these problems with its latest EFI system, the Pro-Flo 4. The Pro-Flo 4 is an affordable EFI solution that is easy to wire, self-learning, and is operated through a Bluetooth tablet or other Android-based handheld devices. Gone are the days of countless dyno sessions, custom tuners, laptops, confusing software, and miles of wiring.
Carburetor Vs. Electronic Fuel Injection
Recently, we spoke with Mark Honsowetz, the EFI Product Manager of Edelbrock, about the Pro-Flo 4 Electronic Fuel Injection (EFI) for the LS engine and some of its advantages over a carbureted setup. Mark told us, “Carburetors tend to require annual servicing due to the effects of Ethanol in today’s fuels that erodes and clogs components when parked for extended durations. Fuel injection systems rarely need such services. Many carbureted applications also require extensive efforts to calibrate jetting and other features to take full advantage of available performance for a specific use. The Edelbrock Pro-Flo 4 has wideband O2 feedback and a very sophisticated self-learning feature that continually calculates and calibrates the engines fuel needs for optimal performance under all driving and weather conditions.”
"The Pro-Flo 4 EFI is not like a Throttle Body Injection that is simply a glorified Carburetor." – Mark Honsowetz
Multi-Port Injection Vs. Throttle Body Injection
It’s pretty apparent that EFI is superior over a carburetor, but is there that much difference between the MPI Pro-Flo 4 unit and TBI? Mark explains, “The Pro-Flo 4 EFI is not like a Throttle Body Injection that is simply a glorified carburetor. Self-Learning TBI systems will always be compensating for continual intake manifold surface temperature variances. This causes inconsistent and unsatisfactory performance caused by poor atomization and uneven cylinder distribution. Pro-Flo 4 is a Sequential Port Fuel Injection system. Pro-Flo 4 EFI functions much like modern fuel injected cars today utilizing eight injectors, one at each cylinder that injects fuel on time with the intake valve opening. This provides the most consistent, balanced performance under all conditions.”
Edelbrock Pro-Flo 4 EFI
There are several things that are intriguing about Edelbrock’s Pro-Flo 4 EFI. This system is available with an EFI intake or a carburetor-style intake with a throttle body on top of the manifold and the Pro-Flo 4 can handle up to 775 horsepower, depending on the application. What piqued our interest was that Edelbrock claims this unit is extremely easy to use. Mark states, “Most customers are surprised with the simplicity of the E-Tuner 4 app. The setup wizard is extremely simple and self-explanatory. The app itself is very intuitive, yet basic, and powerful at the same time. Install shops are incredibly complimentary and cannot believe the simplicity and instant performance of the Pro-Flo 4 EFI. Shops are making more money because expensive and time-consuming dyno sessions and tuning are not necessary with the Pro-Flo 4 EFI and E-Tuner 4 app.”
"Most customers are surprised with the simplicity of the E-Tuner 4 app." – Mark Honsowetz
We have used several EFI systems over the years, and we haven’t found many that are truly effortless. Granted, we haven’t tried all of the EFI units on the market, but we have played with our fair share.
Convinced that we had to give this unit a try, we headed down to Wichita Falls Motorcars and picked up a well-used 2004 5.3-liter out of a Chevrolet Avalanche. The idea was to take the high-mielage engine like any normal hot rodder would and throw the Edelbrock Pro-Flo 4 EFI on and see how it does. We chose the Pro-Flo 4 (PN 35710) for a couple of reasons. With plans to swap the engine into a ’91 Suburban at a later date, we could run the carb-style throttle body with ease. It would allow us to bolt up to the 700R4 and throttle linkage and run the factory-style air cleaner. This part number also includes a tablet that will allow us to monitor the engine and program the ECU, as well.
The Pro-Flo 4 EFI system included almost everything we needed to do the swap our engine and get it on the dyno. The system came with a cast aluminum intake manifold, throttle body, fuel injectors, fuel rails, sensors, fittings, hardware, ECU, wiring harness, tablet, and detailed instructions. You will need to order the Ignition/IAC Harness harness, but we we’ll into that later.
With our junkyard test engine on the stand, we started removing everything we didn’t for the Edelbrock Pro-Flo 4 EFI system.
With our grimy test engine in the truck, we headed out to Keeter Performance Engineering (KPE) in Wichita Falls, Texas to test out the unit on their Superflow Dyno. Tommy Keeter, Owner of KPE, has years of experience with both mechanical injection, carburetors, and electronic fuel injection. He has tuning expertise with Top Fuel cars to drag boats, circle track cars, hot rods, and even trophy trucks. Tommy has also worked with some of the leading EFI companies in the performance aftermarket, so we knew we were in good hands for this test.
Pro-Flo 4 EFI Installation
When we said the engine was dirty, we weren't joking. Dirt and grime covered the 5.3 from top to bottom.
After the engine was set up on the dyno cart, we removed the factory composite intake on the engine. With the intake manifold off, it was apparent that the 5.3 had a pretty rough life and was remarkably dirty. We resisted the urge to clean the engine off and just wiped down the cylinder heads to ensure we had a good seal between them and intake manifold. We then dropped the Pro-Flo 4 intake on the 5.3 and bolted it down with zero problems. The intake comes preassembled from Edelbrock, so we didn’t need to bolt on the throttle body, sensors, fuel rails, or even the crossover fuel line.
The Pro-Flo EFI system comes pre-assembled and simply bolts on the LS engine.
Next up, it was time to hook up the wiring harness. Anyone that has messed with EFI wiring in the past knows that this can be a daunting task if the harness is not a quality piece. Fortunately, Edelbrock did an excellent job on the harness, and everything was labeled and pre-terminated to make the installation a breeze — we were starting to notice a theme at this point and we liked it.
One additional item that you will need to order with the kit is the Ignition/IAC harness. Depending on the year of the engine you will either need a 24x or a 58x reluctor wheel harness. Since our engine was a Gen III, we need the 24x (PN 35713). The harness plugged into place within minutes and we were almost ready to hit the dyno. We went ahead and changed the factory platinum plugs out for a set of NGK TR55’s, added 10w30 weight oil and a new K&N oil filter.
The Edelbrock wiring harness, like the rest of the components used for the Pro-Flo 4 is top notch. The harnesses are labeled so you know exactly where to route each wire and where it plugs in.
Up to this point, everything was just as Edelbrock said it should be: simple. Now it was time to start the engine and tune it. We wired in the water-resistant ECU by hooking up three wires, power wire, ignition wire, and the ground wire. All that was left was bolting on a set of headers, screw in the supplied O2 sensor, and connect it to the Edelbrock harness.
The next step in the process was to set up the ECU. Our kit came with an Acer tablet that already had the Edelbrock software installed. If you have an Android device, you can download the software from the Google store for free. Tommy turned on the ignition for the ECU, and we hit the connect engine icon at the top right of the screen. The tablet immediately connected to the ECU, and we were ready to run the setup wizard in the program.
Engine Start Up
The tablet and Pro-Flo 4 app performed flawlessly. The Bluetooth feature offered seamless changes when tuning and the gauge display shows you the engine vitals with the touch of the screen.
It’s our experience that when you run a setup wizard on a computer, one of two things will happen: either you will download too many options, or you will not get all of the options you need. Skeptical, we clicked the wizard icon button and initiated the process. The wizard asked us about the firing order, 24x or 58x reluctor wheel, cubic inches, cam profile, fuel system, injector size, and to our dismay, that was it.
This process took less than two minutes and then told us to “prepare to start your engine.” Puzzled, I looked at Tommy and said, “prepare to start the engine?” Tommy glanced back in disbelief and said, “Are you sure?” At this point, we were not. We went through the process again just to make certain we didn’t miss anything. Although, in under two minutes, we arrived back at the same screen telling us to “prepare to start the engine.” Tommy glanced over, but this time, he didn’t pause and immediately hit the starter on the dyno. Instantly, the used 5.3 roared to life and idled smoothly.
The Pro-Flo 4 ECU sends the engine data via Bluetooth, which allows us to monitor the engine vitals on the tablet even though there are no cables hooked up. The engine ran for about five minutes before it got up to 165-degrees. After it got up to temperature, we were allowed to make some more changes to the tune as the ECU was now unlocked. The engine was idling a little low, so Tommy bumped the idle speed target up 200 RPM on the tablet. Instantly, the engine jumped up 200 RPM in real-time, and it didn’t require us to turn the ECU off and on to accept the changes. Within ten minutes, we were done with the setup process.
The stock engine was locked and loaded for our first round of dyno pulls. Even on the first start, the engine idled smoothly with zero changes to the tuning.
By now, Tommy had gained some confidence in the Pro-Flo 4 unit. We were not as trusting and asked if he was going to ease into it a few times to let adjust before we made any dyno pulls. Tommy replied, “Nope! Shut the door and let’s make some pulls!” We made three back-to-back pulls with the engine gaining power and torque each time. Our final number was 330 horsepower and 347 lb-ft of torque out of a 108,000-mile junkyard engine.
With the little LS still idling on the dyno, Tommy said, “I’m going to see if I can make it stumble.” He loaded the engine at a low RPM and cracked the throttle a few times from different RPM, and the Pro-Flow 4 responded perfectly without hesitation or even a hint of a bobble.
Upping The Power With COMP Cams
Initially, we were only going to dyno the engine stock, but the test went too smoothly — that, and we are gluttons for punishment. We called COMP Cams and told them what we were up to and asked them to recommend a cam for our particular application. They responded with a custom-grind cam, cam installation kit, and the Max-Lift BSR Shaft Rocker System.
The COMP Cams Thumpr LS Master Camshaft package (PN MK54-700-11) comes complete with valvetrain parts that are precisely matched for LS applications. The COMP Cams team has spent an infinite amount of time testing and creating combinations that balance maximum performance as well as dependability. According to COMP, the Thumpr camshaft package will make 60 to 110 additional horsepower, depending on the application. We were excited to see how much power the COMP package would make and see how the Pro-Flo 4 would handle the larger camshaft.
Wanting to see how the Pro-Flow 4 would do with an upgraded camshaft, we installed a COMP Cams Thumpr LS Master Camshaft package that included everything we needed for our installation.
After we installed all of the goodies from COMP in the 5.3-liter, it was time to do something with the factory rockers. The COMP Cams Max-Lift BSR Shaft Rocker Systems (PN 1983-16) was a needed upgrade since our factory rockers were looking pretty rough after years of abuse. This design is a simple yet excellent improvement over the factory design. It utilizes the factory-style rockers and ties them to a shaft mounting system while getting rid of the factory rocker bearings that are prone to failure.
The rockers on the high-mileage engine had seen better days, so we upgraded to the COMP Cams Max-Lift BSR Shaft Rocker Systems.
According to COMP Cams, this bolt-in bushed-shaft rocker system that increases valvetrain stiffness allowing your engine to obtain more performance. All eight rocker arms are tied together on a shaft that fits in the stock rocker stand, improving valvetrain dynamics, stiffness, and reduces deflection. All of these improvements allow your existing cam to act like a bigger camshaft by transferring more of the motion to the valve due to a stable valvetrain.
Dyno Session Part 2
Tommy Keeter, owner of KPE Racing ran the dyno and monitored all of the vitals. The Pro Flo 4 performed flawlessly no matter what we through its way.
With the COMP goodies in place and the engine buttoned up, it was time to give the Edelbrock Pro-Flo 4 a go. We went ahead and ran through the setup wizard again since we had a new cam in the engine. Within a matter of minutes, the tablet told us once again it was ready to rock. Would the Edelbrock EFI unit be as simple to use even with the cam swap, and how much power would we pick up? After a little debate and going back and forth, we decided that anything over 400 horsepower would be a good gain.
Tommy once again hit the ignition switch and the 5.3 roared to life. The engine was no longer a mild-sounding, smooth-running machine. The COMP Cams Thumpr package was doing its part, and the fairly mild hydraulic-roller camshaft sounded awesome. Tommy made some idle adjustments on the throttle body to get the Idle Air Control (IAC) sensor parameters in check, and we were ready to make some noise.
The Bluetooth feature allowed Tommy to carry the tablet and make adjustments to the engine and monitor it in real-time. Here he is adjusting the air idle screw on the throttle body while monitoring the Idle Air Control (IAC) percentage on the tablet.
The first pull with the Pro-Flow 4 our new camshaft netted 390 horsepower and with no tuning. This was a gain of 60 horsepower… but we had a problem. The engine was still making power when it hit the rev-limiter. Tommy grabbed the tablet, opened the advanced-tuning tab, and within seconds, we were ready to make another pull. On our second pull, we hit our 400 horsepower mark and we were stoked. Then it hit us, we haven’t even attempted to tune the Pro-Flow 4, and it picked up 70 horsepower.
Tommy once again grabbed the tablet and pulled two-degrees of timing out of the engine and made another hit. The 5.3 didn’t like the change and lost power. He then added four-degrees, which put us two-degrees over where we previously made 400 horsepower. This adjustment the engine wanted, and it revved up effortlessly. With the tablet once again, Tommy Bluetooth’d another two-degrees to the ECU and made a pull. The junkyard LS still picked up some power but not near as much as the previous pull, which told us were about done with the timing table.
Have you ever seen a better-looking set of spark plugs with no tuning? We were blown away at how good this unit is right out of the box.
Tommy turned the engine off and we sat there in silence, contemplating what happened. Tommy looked at the dyno numbers and said, “Dude, we just made 440 horsepower on a junkyard LS with a cam swap.” He was right! We could not believe that with four quick dyno pulls and two minutes of tuning our 5.3 LS engine picked up 110 horsepower. The junkyard 5.3 made 440 horsepower at 6,200 rpm and 400 lb-ft of torque at 4,800 rpm. Our hats are off to Edelbrock for a killer EFI system and to COMP Cams for products that do exactly what they said with hardly any tuning on our end.
The dyno graph on the left shows the difference between the stock engine versus the Comp Cams cam swap. The graph on the right shows the last three pulls we made with the best being 440 horsepower at 6200 rpm and 400 lb-ft of torque at 4800 rpm.
Pro-Flo EFI 4 - Recap
After the dyno session, we spoke with Tommy to get his thoughts on the Pro-Flo 4 EFI system. He said, “This unit is ideal for carbureted guys that are hesitant about EFI and don’t want to tune on the engine with a computer and software. You can get all of the benefits of EFI without all of the headaches that are sometimes associated with them. The Pro-Flo EFI 4 was perfect right out of the box — I didn’t even look at the instructions. I took the tablet and pushed a few buttons. It’s very intuitive and easy to navigate.”
It Only Gets Better
As good as the Pro-Flo 4 is — and it’s absolutely awesome — there are a couple of additions we would like to see in the future.
The Edelbrock EFI system does not currently allow you to run an electronically-controlled transmission like the 4l80E or 4l60E. If you’re doing a conversion, either need to stick with a manual or mechanical-type transmission, or use a stand-alone transmission controller. Another option we want to see is the use of power-adders. Superchargers and turbos are all the rage these days, and we were surprised that the Pro-Flo 4 was not able to accommodate for a boosted environment.
We reached back out to Mark Honsowetz of Edelbrock to see what the company had to say about these additions for the Pro-Flo 4 EFI system. Mark noted, “For power-adders, we have a new release for the E-Tuner 4 App. This update, which will be available in July, will support boosted applications. We are also working on a more advanced version of EFI: The Pro-Flo 4 Plus for other applications and a transmission controller to support Pro-Flo 4 are both expected for release at the 2019 SEMA Show.”
This update from Edelbrock is fantastic news. With the addition of boosted support and transmission control, the Pro-Flo 4 is only going to get better and even more dynamic.
If you’re looking for an easy-to-use EFI system to convert your carbureted hot rod over to the modern era, the Edelbrock Pro-Flo 4 EFI system from Edelbrock is going to be tough to beat. The ECU is compact and can be mounted virtually anywhere. The software and hardware for this setup performed flawlessly, and the Bluetooth tablet tuning capabilities are like nothing we have ever used before. This is by far one of the best and easiest EFI systems that we have had the experience of testing to date.
Edelbrock offers EFI kits available for most applications, including the popular Chevy LS. If you are planning on running the factory LS fuel injection, you can purchase the Pro-Flo 4 EFI – ECU & Engine Harness Kit for GEN III 24x LS Engines, for only $XXX. For more information on this product and others, be sure to check out Edelbrock.com.
Other products to help your LS Swap:
Without a doubt swapping an LS motor into pretty much anything with wheels has become the largest hot rodding trend we have seen in a long time. We have some of the top 250 LS swap components that you are looking for.
- LS Power - Top LS Swap parts
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Books to read before an LS Swap:
- LS Swaps: How to Swap GM LS Engines into Almost Anything
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