A Deep Dive Into FAST’s XFI Sportsman EFI On Biting The Bullitt

XFIlead copy

Project Biting The Bullitt is nearing completion, with the Dart-based 427 cubic inch engine, Paxton NOVI-2500 supercharger, and TCI Super Streetfighter 4L80E transmission onboard, the car makes plenty of power and gets it to the ground efficiently. The car stops the clocks with nine-second elapsed times and does it in style, thanks to a fresh hue applied by JEP Autoworks with DuPont materials.

Biting The Bullitt has been an ongoing project for the better part of three years at this point, and its culmination this summer has focused around getting all of the final details in order, from the new paint to parachute. For the body and paint article, we removed and reinstalled the engine in the car – which gave us the perfect opportunity for yet another upgrade.

You may remember that BTB was using a blow-through carburetor system for fuel metering in the past, but thanks to the main focus of today’s article, the brand-new XFI Sportsman EFI system and XFI eDash from FAST, we’ve ended the summer with the installation of electronic fuel injection on the big-power Bullitt.

Once the car returned from JEP Autoworks, the thrash was on to complete the reinstallation of our Dart-based engine and get the XFI Sportman into place.

Once the car returned from JEP Autoworks with its fresh coat of DuPont paint, the thrash was on to complete the reinstallation of our Dart-based engine and get the XFI Sportman into place.

The XFI four-hole throttle body atop our Edelbrock intake manifold fits right in place of our old carburetor setup.

The XFI four-hole throttle body atop our Edelbrock intake manifold fits right in place of our old carburetor setup.

These items will serve to simplify the tuning process on our ’65 and give us many capabilities to control the engine with greater control and precision than currently exists. When we say simple, we mean really simple – installation is a snap, and if you’ve ever worked with tuning software in the past, XFI’s C-Com software will be familiar to you. If not, then you can use the self-tuning option and be off to the races as you learn the capabilities of your new system.

What It Is

The XFI Sportsman ECU is small enough to tuck out of the way in our glovebox for easy access.

The XFI Sportsman ECU is small enough to tuck out of the way in our glovebox for easy access.

The XFI Sportsman electronic fuel injection system fills a hole in the middle of the FAST lineup; the company previously had the EZ-EFI and XFI 2.0 systems available, targeted at the muscle car crowd and hardcore racers respectively, but no system in the middle to satisfy the enthusiast who does spend some time racing but also spends time cruising.

That’s exactly where the XFI Sportsman comes into play – especially with boosted applications like ours, which aren’t supported by the EZ-EFI.

“This system is set to work perfectly on those cars with an identity crisis – the ones that don’t know if they’re a race car or a street car. There are a lot of those out there, from muscle cars to street rods with blowers, nitrous cars, turbo cars, blower cars – but they don’t do sanctioned racing, and they don’t necessarily need all of the features that the XFI 2.0 offers,” says FAST’s David Page.

Here in the Startup Wizard is where you define specific operating parameters of the engine; the number of cylinders, fuel injector flow rates, MAP sensor capabilities, and so on. Note that our fuel energy constant with E85 needs to be set at .680 - gasoline would be 1.00.  Also, our injectors are actually 125 lb./hr. injectors, but running at our 58 psi fuel pressure, they become 131 lb./hr. injectors. The fuel cut off and on is your rev limiter - it will cut fuel at 6,600RPM, and start delivering fuel again when the engine speed drops below 6,400 RPM.

Here in the Startup Wizard is where you define specific operating parameters of the engine; the number of cylinders, fuel injector flow rates, MAP sensor capabilities, and so on. Note that our fuel energy constant with E85 needs to be set at .680 – gasoline would be 1.00. Also, our injectors are actually 125 lb./hr. injectors, but running at our 58 psi fuel pressure, they become 131 lb./hr. injectors. The fuel cut off and on is your rev limiter – it will cut fuel at 6,600 rpm, and start delivering fuel again when the engine speed drops below 6,400 rpm.

The XFI Sportsman offers many of the features found in the XFI 2.0 system, along with many of the features of the EZ-EFI system – packaging them into one easy-to-install, highly capable self-learning EFI unit that gives that ‘tweener enthusiast exactly the control they need over their machine’s performance.

Left: The XFI Sportsman can be set in Adaptive Learn mode, pictured here, where the user sets minimum values, enables the learning mode, and lets the system do the bulk of the work. You may need to disable Adaptive Learning at idle if using a large overlap camshaft, so that's why it's set to turn on above 1,100 rpm. The Adaptive function is excellent for setting the target air/fuel ratio for the system to work towards on the fly when it is in closed loop. Adaptive Learning will help immensely in correcting the tune for drivability. Right: The system is also fully capable of datalogging each of the operating parameters as shown here; each one can also be turned on or off to suit your needs. The datalogger can also be set up to activate or de-activate depending upon conditions, like wide open throttle or coolant temperature or whatever parameter you'd like -- or it can be turned on and off manually.

The system works for all of the aforementioned types of engine combinations using a bank-to-bank fully programmable electronic fuel injection setup. Unlike the EZ-EFI, which does not require an external laptop connection, one is required to set up the XFI Sportsman system, using FASTs C-Com software package – just like the XFI 2.0. The system ships with an ECU, wiring harnesses, wideband oxygen sensor, and electronic fuel pressure kit.

Left: The multi-port harness pictured here plugs into the main harness and can just be laid into place in the engine compartment and plugged into the supplied sensors. Right: The complete wiring harness with the multi-port harness.

One of the features that attracted us to the XFI Sportsman initially was its advertised ease of use – with a pre-terminated harness, and sensors that are located in easy-to-reach, easy to plug-in locations, it would be the perfect upgrade for us to switch from the carbureted setup. More on this further into the article.

The throttle position sensor and IAT sensor are built into the throttle body's spacer ring.

The throttle position sensor and Idle Air Control sensor are built into the throttle body, the Intake Air Temperature sensor into the spacer above, and all three are simple plug-ins.

The sensor package that allows the XFI Sportsman to work is quite simple. There’s an included wideband oxygen sensor, LS-style injector harnesses, and EV14-style adapters to work with our injectors. Our manifold has a position for the coolant temperature sensor built-in; in fact, Ford manifolds have two ports for coolant temp sensors – our second one is filled by the sensor for our Racepak system.

Left: The Acceleration Enrichment Fuel versus Air Temp graph. This is an enrichment table that takes fuel out of the engine as it warms up. As the air gets warmer you come to a zero point around 85 degrees, and then as the air becomes hotter and less dense you start pulling fuel. Middle: This graph is AE fuel versus coolant temperature. 'The engine's need for extra fuel as the throttle is opened (pump squirt) changes with air temp and coolant temp. These tables allow the user to tailor the optimum acceleration enrichment (pump squirt) for the engine relative to air and coolant temp,' says Page. Right: Here we're looking at the AE Fuel versus TPS. This ramps in fuel depending on how quickly you ramp in the throttle. As you hammer the throttle, you have to tune in the rate and overall enrichment to get this ramp as smooth as possible so the engine doesn't stumble off the starting line. If the pulsewidth is too high it will add too much fuel, and if it's too low, then the engine will be too lean.

Page explains that the system differs from the XFI 2.0 in the bells-and-whistles type features. For example, you can run nitrous oxide, but the system won’t control it in a progressive manner like the 2.0. There is no built-in transbrake control, nor is there traction control. In terms of spark and fuel, it offers full tunability just like the XFI 2.0.

What It Does

The features of the XFI Sportsman are vast; while it does not have the full features of the XFI 2.0, the system does offer tables to monitor and adjust fuel, timing, and air/fuel targets. The auxiliary input channel is configurable by the user, and the system also includes a full-function datalogger. Not only does it work well on naturally aspirated combinations, boosted combinations making up to 5 bar of boost are fully supported. There’s also timing retard built in for nitrous users with wet nitrous systems.

Reading the main Volumetric Efficiency map clues us in to a few items abut Biting The Bullitt's engine. On the left side of the graph is load, RPM is at the bottom. 100 kPa is zero vacuum (or atmospheric pressure), 200 kPa is 14.7 psi of boost (1 bar). This engine runs just above that, but since there is a 3 bar map sensor, the graph reads to 300kPa.

Reading the main Volumetric Efficiency map clues us in to a few items about Biting The Bullitt’s engine. On the left side of the graph is load (kPa), RPM is at the bottom. 100 kPa is zero vacuum (or atmospheric pressure), 200 kPa is 14.7 psi of boost (1 bar). This engine runs just above that, but since there is a 3 bar map sensor, the graph reads to 300 kPa. As BTB’s engine is boosted, the VE exceeds 100% towards the top right of the graph, but a typical NA engine should never be above 95 percent or so.

With the onboard CAN network, the XFI Sportsman will work with the rest of FAST’s computer components – the EZ-TCU transmission controller, EZ-LS GM ignition controller, XIM Ford Modular ignition module, and eDash touchscreen unit all interface simply and easily in a plug-and-play fashion. We used an eDash in this application – read more about it below.

The eDash will monitor many different parameters, and even tell you when the nitrous is activated, or there's been a system error.

The eDash will monitor many different parameters, and even tell you when the nitrous is activated, or if there’s been a system error.

The system also features the same self-tuning strategy offered in the EZ-EFI; utilizing the built-in Bosch wideband oxygen sensor, the XFI Sportsman is smart enough to tune itself on a naturally aspirated combination once you set the appropriate target air/fuel ratio desired. This feature is enabled and disabled by the user. For boosted combinations, the startup tune will get you close, but it’s recommended to have one of the many FAST tuners across the country dial it in while you’re learning the system. If you’ve tuned a boosted car before, you have a leg up on the process.

Tuning Variables

Simplicity reigns with the throttle body assembly.

Simplicity reigns with the throttle body assembly.

The XFI Sportsman system is able to use either Speed Density or Alpha-N fuel strategies; although most users will be just fine with the Speed Density setup, the Alpha-N option is there for situations where it is required.

“Speed Density uses air temperature and air pressure as part of its fuel calculations so it always keeps the fuel inline with the changing air. In my professional opinion, Speed Density offers the most consistent performance. This opinion has been developed through years of tuning NHRA Stock Eliminator and Super Stock cars. Alpha-N can work well when there is no stable manifold vacuum source such as in a true individual runner induction system, or if the tuner simply prefers this strategy,” says Page.

Sensors are easily installed, and the harness just plugs right in - no wiring to do for the end-user. This is one of the features that attracted us to the XFI Sportsman system.

The Speed Density tuning strategy uses atmospheric pressure measured by the MAP sensor and air temperature to calculate the density of a given volume of air in the engine under specific atmospheric conditions. The ECU calculates the air density using these parameters, and subsequently needs to know the volume (displacement) of the engine and the desired air/fuel ratio to calculate how much fuel to inject to meet the target.

Here's a three-dimensional view of the fuel map, from low load on the left to high load VE on the right. It's important to check over the map to make sure you have a smooth transition and there are no peaks and valleys.

Here’s a three-dimensional view of the fuel map, from low load on the left to high load VE on the right. It’s important to check over the map to make sure you have a smooth transition and there are no out-of-place peaks and valleys.

The DeatschWerks DV2 Injector

With the management of the engine’s parameters out of the way, we needed a way to supply the fuel to the engine, and to that end we selected a set of DeatschWerks‘ brand-new DV2 1200cc fuel injectors. These are one of the largest high impedence Bosch injectors you can get with the EV14 technology and offer a number of advantages to our program. They are a simple plug-in using the XFI Sportsman’s included adapter connectors.

These injectors are flow-matched using DeatschWerks’ multi-point dynamic flow testing. Perhaps most important for our application, they’re compatible with race fuels including MTBE oxygenated fuels, ethanol-blended fuels including E85, and methanol-blended fuels. The injectors are shipped with comprehensive injector characterization data, which allows the tuner to make more informed decisions when tuning and gives better idle, drivability, and power-enhancing characteristics. One thing we learned during the initial XFI Sportsman base map setup was how important it is to verify the injector data based on intended fuel pressure – the injector’s performance is different at 3 bar and 4 bar of pressure.

“The ECU uses the same standard constant laws of physics about the relationship of the density of air to the Pressure and Temperature as your weather stations and all dynos use. Once the ECU has calculated the density of the air, it just needs to know the volume and your desired air/fuel ratio to calculate how much fuel to put into the engine. The displacement of the engine is a constant so the VE or Volumetric Efficiency is the variable that you use to properly calibrate your system. The VE is a measure of how well the cylinders are being filled compared to their potential volume. Once you have found the VE value that causes the engine to run at your desired or target air/fuel ratio with no O2 or other corrections, then you have discovered the accurate VE for your engine at that particular load and speed in that particular cell in the VE table,” explains Page.

The engine will need more fuel to get to the same air/fuel ratio at a near-seal level race track, but once the VE table is properly calibrated, there exists an accurate Air Flow table for the engine. With the VE table properly calibrated in Speed Density mode, the fuel table will not have to be adjusted from track to track – the ECU will perform these calibrations for the user.

Since the engine doesn’t know how the XFI Sportsman decides how much fuel to inject, as long as the parameters are calibrated properly, both Speed Density and Alpha-N fueling strategies can and have been highly successful in racing operations – it’s up to the user to decide which route they’d like to select.

Volumetric Efficiency of the engine doesn’t change unless parts are changed to improve or hinder airflow, so the engine will move the same volume of air in two completely different locales – for example Las Vegas and South Georgia Motorsports Park — but the air at SGMP would be more dense due to its close-to-sea-level elevation and overall better conditions.

eDash Is In Control

You get the benefits of self-learning with the adjustability you need to tune it yourself. – David Page, FAST

With the installation of our XFI Sportsman system, we also elected to upgrade the car with one of FASTs new XFI eDash units, which provides a number of unique features and works with both the Sportsman and XFI 2.0 engine management systems.

The full-color, touchscreen eDash uses a single plug-and-play harness to connect with our XFI Sportsman system, providing a compact digital dash unit that can display up to 20 live data readings – even all 20 at once – and mounts to the window or dash with a simple suction cup. The data screens can also be shown on various electronic digital dashes that include commonly-viewed sensors. Live sensor readings include Idle Air Control, Total Timing, Miles Per Gallon, O2 Correction %, Coolant Temperature, Fuel Pump Duty Cycle, and more – proving useful for both the street enthusiast and racer with the wide variety of data that is displayed.

The eDash will even tell you if there is an issue with any of the installed engine sensors.

The eDash will even tell you if there is an issue with any of the installed engine sensors.

The Adaptive Learning settings, Torque Converter lockup MPH, and Rev Limiter can all be adjusted through the eDash for the XFI Sportsman, and XFI 2.0 users gain the ability to load four different tunes and control power-adder on-off settings (like boost control or nitrous control) on the fly with the eDash.

The system also uses the same mounting points as the Garmin GPS, meaning that an eDash owner could find a Garmin dash mount for their vehicle and install the eDash right into the mount for an even cleaner appearance.

Other Parts We Needed From Edelbrock, Russell, and Deatschwerks

In an effort to keep things simple, we hooked up with the guys at Edelbrock to get set up with one of their Super Victor 351W EFI manifolds [PN 29245] and a set of fuel rails to match [PN 3620]. Since our carbureted combination used a Super Victor manifold, the installation of this new manifold means no plumbing changes — we could just attach the existing bonnet to our new throttle body and go.

With FAST’s throttle body on top to process the air, we needed to supply the fuel, which we did with a set of Deatschwerks DV2 injectors (see sidebar) sucking fuel through a set of Edelbrock’s fuel rails [PN 3620]. An assortment of hose and fittings from Russell Performance helped to make everything copacetic, and it was time to hook up the whole works under the hood of Biting The Bullitt.

An Edelbrock Super Victor EFI intake manifold, the company's high-flow fuel rails, and Russell Performance fittings were used to convert the car over from its former carbureted lifestyle to the current fuel-injected state. The throttle body uses the same bolt pattern as a standard 4150 carburetor, making installation a snap.

We had a complete assortment of Russell’s ProClassic black-08 AN fittings on hand, including the Y-Block pictured above to use with the company’s ProClassic II hose to run our fuel lines for this project. ProClassic II hose uses an all-black nylon fiber braided outer cover over the synthetic rubber inner line. Where the ProClassic II hose stands out from the pack is through its use of an internally bonded multi-braid stainless wire. This feature improves the bend radius of the hose, while reducing the chance of it collapsing when used in tight spaces like our Mustang’s engine bay. It’s compatible with fuel, oil, and antifreeze, and is rated to 350 pounds per square inch of pressure.

A Simple Install

Installing the system is unlike any other standalone engine management system; the harness is pre-terminated from FAST and plugs right into the sensors that are required on the engine, so the user doesn’t have to spend endless days terminating harnesses and trying to figure out what goes where. The system is designed to offer the user a plug-and-play layout where the pre-made harness can be laid out into the engine bay and simply plugged into the required sensors and go racing. In addition, it’s the same harness that’s included with the EZ-EFI system, so a user can upgrade from that to the XFI Sportsman without having to completely rewire their car.

“The XFI Sportsman system offers unique tuning considerations that aren’t offered elsewhere. You can set it to self-learn above a certain throttle percentage but in a difficult or challenging area of the tuneup, like idle tune, you can jump in there and manually tune that yourself. You get the benefits of self-learning with the adjustability you need to tune it yourself,” says Page.

Left: The spark advance versus load table shows that the engine idles with 23 degrees of timing. As load and RPM goes up, timing is removed, while at the lower portion of the graph timing is added to help keep the car from stalling should it be at those parameters. Left Middle: Spark versus air temperature graph. This one is easy - as air temperature goes up above 120 degrees, ignition timing is pulled gradually to preserve the engine as the intake air heats up. Right Middle: Target Lambda versus RPM and Load. This is Closed Loop compensation. The system will run off this map. When you're in Adaptive Learning mode, the system is reverting to this map. The system will take the engine's actual air/fuel ratio and the target Lambda, and try to blend the two together. Right: The Throttle Follower table shows IAC position versus TPS position. The further down this graph can be run, the better the idle will be. This car runs in the 60-count range, but a naturally-aspirated car might run in the 20s range. This could be interpreted as duty cycle of the IAC motor.

Wrapping Up

There is much more to FAST’s new XFI Sportsman system than we can possibly cover here, but we can say that it’s offered Project Biting The Bullitt a new lease on life. Installing the system onto the car had us pumping out 824.5 horsepower on the dyno and gaining a serious handle on the drivability of the car.

From the beginning of the Biting the Bullitt project to the end - that's a serious gain in horsepower and performance at the track, yet the car still remains completely streetable.

From the beginning of the Biting the Bullitt project to the end – that’s a serious gain in horsepower and performance at the track, yet the car still remains completely streetable. 824.5 horsepower all day long on E85 fuel.

While our old setup was dialed-in pretty well, the XFI Sportsman system has the engine lighting off immediately and settling into a nice idle – sounding about as refined as nearly 1,000 crankshaft horsepower can be, while making boatloads of power. We can’t wait to check out some of the other tuning features when it’s time to go to the track!

On the dyno -

On the Dynojet dynamometer, 824.5 horsepower is our final reading. Power Automedia Editorial Director Mark Gearhart actually cruises this beast to work on occasion.

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About the author

Jason Reiss

Jason draws on over 15 years of experience in the automotive publishing industry, and collaborates with many of the industry's movers and shakers to create compelling technical articles and high-quality race coverage.
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