Breaking down the Haltech Nexus R5 Vehicle Control Unit in a 7-second Mustang
Written by Michael Galimi
Photography by the author
The integration and merging of technology is happening across all areas of our lives, some of it is readily apparent and some of it is not so obvious. Home entertainment used to be a simple television set, and after 50 years, it is being shoved aside by various hand-held devices. Those same devices act as phones, gaming consoles, and are capable of controlling a vast number of household functions. If technological integration is happening with entertainment and communication, then it is most certainly occurring in other aspects of our lives, like in the world of hot rodding.
Aftermarket engine management companies evolved into highly comprehensive technology providers, creating software and hardware solutions to help us go quicker and faster. These advancements see continued success off the track and in the street market where ultimate control is paramount to street worthiness. Haltech’s latest control unit to hit the market is the Nexus R5. We are hesitant to call it an ECU because it is so much more than an engine control unit. The Nexus R5 combines the functions of an ECU, power distribution module, and data logger into what Haltech describes as a Vehicle Control Unit.
To our knowledge, Haltech is the first to market a VCU in our niche motorsport segment and there are several benefits to the Nexus R5. The larger packaging of the VCU box allows for a significant increase in connections, eliminating the days of adding multiple input/output boxes or having to make the hard decisions on which sensor or control gets priority over another. A quick scan of the literature reveals 60 outputs and 40 inputs, allowing for extensive control and sensor data collection.
By offering direct, high-amperage outputs, it eliminates most or all relays, and enables the use of an efficient and reliable CAN-based keypad and/or CAN-based hub. Using a single CAN connection for up to 15 different functions not only simplifies wiring, but also adds a tremendous amount of flexibility with its software-based configuration.
Engine Management System
The Nexus R5 uses completely new software to go along with the hardware upgrade, but it still packs the features of the company’s popular Elite 2500T. It includes 18 fuel-injector drivers, 12 ignition drivers, nitrous controller, boost controller, and an auto transmission controller. Additionally, the VCU is capable of controlling a drive-by-wire throttle body (single or dual) along with variable camshaft timing in single- or multiple-cam applications. And—like all Haltech Elite series ECUs—the Nexus R5 is suitable for four-, six-, and eight-cylinder engines, as well as Rotary-style platforms.
The Haltech NSP software reveals tuning in 4D format, allowing the user to tune by gear, cam angle, or any other channel for ultimate flexibility. As a side note, this 4D format came in handy with our test vehicle when switching back and forth between pump gas and VP Racing Fuels C16 as it balances a street/race lifestyle. The fuel, ignition, boost, and idle control learning are adjustable in short and long trim. The Nexus R5 is compatible with high- or low-impedance fuel injectors and programmable peak-and-hold current capabilities. Dual knock control enables users to build in safety elements for engine protection; in fact virtually any engine sensor can be used for fail-safe protection. The addition of a flex-fuel sensor makes it easy to change fuels without requiring a re-tune.
The internal boost controller is a closed-loop system and offers several modes to custom tailor the curve when managing the power output of your boosted engine. The boost levels are adjustable using gear, wheel speed, or time thresholds. The CAN keypad, an additional product from Haltech, also allows the user to switch between boost ramps on the fly to adapt to changing track conditions. The dual-bank O2 sensors have a closed-loop mode for precise tuning.
For the drag racing crowd, as well as those interested in rally racing, there are anti-lag and launch control functions. The aforementioned nitrous controller is capable of handling up to six-stages of laughing gas with provisions for fuel and timing control, so the systems can be run dry.
One nifty option that is becoming more popular is the Nexus R5’s ability to control transmission functions. It triggers a pneumatic or electronic solenoid for shifter activation or assumes command over various popular, electronically controlled OEM transmissions like the 4L80E.
The Nexus R5 offers torque management/traction control for small-tire or no/minimal prep-type racing. The torque-management function uses driveshaft rpm for its input, while conventional traction control references front-to-rear wheel speed differential. Typically, tuners will rely on torque management and driveshaft rpm early in the run and transition to the wheel speed differential when there is sufficient vehicle speed. This ensures the torque management doesn’t slow the car down on a better-than-normal run.
Power Distribution Module
A Power Distribution Module is designed to distribute power to multiple circuits throughout the vehicle. We’ve seen several great PDMs on the market but this is the first one we’ve seen integrated with the ECU. The simplicity of wiring and reliability are obvious advantages when using a PDM, but there is so much more that it offers. Using Haltech’s software, the user has access to pre-configured commands to control sensors or other functions, which can be implemented for safety and engine reliability safeguards. The PDM can also switch various systems on and off using various inputs.
For example, the Haltech software can use water temperature to activate cooling fans or a specific strategy for water pump operation. The Nexus R5 turns on the water pump in our test vehicle when the engine speed is 500 rpm or higher, and the Boost controller is activated with the arming button on the keypad. The boost-control sequence resets when the transbrake is pushed, launch boost is applied while the transbrake is on, and a timed-based ramp starts when it is released. Street cars benefit by running blinkers and headlights through the PDM, making it easy to configure the IC-7 dash and show the driver that those functions are operational.
Much like the Elite 2500, the Nexus R5 is capable of data-logging any sensor that is connected to the VCU. Additionally, the Nexus R5 monitors vehicle dynamics with G-force and rotational movement such as latitudinal and longitudinal yaw. The VCU contains an internal accelerometer and users can also add a G-meter through an analog channel or CAN connection. Using one unit doesn’t just simplify the hardware installation, but also software integration for easy analysis. The data logs can interface with engine-management functions allowing the tuner to make the most educated decisions. The data records at a 5/ms sample rate and offers 1mb of internal storage.
Haltech has made it easier to connect to the VCU by adding WiFi, allowing remote tuning from your trailer or halfway around the world. And if you’re old school and prefer using a cable to connect to your laptop or PC, simply plug in the cord and go—you don’t even need to have the vehicle’s power on to do so.
The list of features is extensive and Haltech published a series of videos breaking it all down. However, we wanted to see the Nexus R5 in action and who better to create a firsthand account of its functionality than our buddy Mike Jovanis. The New Jersey racer is no stranger to these pages with his QA1 True Street machine. The 1989 Mustang LX has been a best of 7.55 at 181 mph and Jovanis has collected ten QA1 True Street Overall victories in NMRA competition.
Jovanis’ familiarity with Haltech products goes back to 2013 when an aging standalone EFI system showed signs that it was time to move on to something better. He connected with one of Haltech’s reps on the once-popular TurboForums.com website and slipped into a Haltech Platinum series ECU. Fast-forward to 2016 and he made the switch to the newer Elite 2500T, eliminating all third-party boxes and bringing all of the engine functions under Haltech’s control. After four years of service, Jovanis was one of the first to jump at the opportunity to make the switch to the Nexus R5, further consolidating the electronic functions and simplifying the wiring on his mid-7-second street car.
Swapping from an ECU with separate relays and power management to the Nexus R5 takes some work because the VCU is an all-in-one PDM and ECU. Jovanis worked with Haltech to develop a parts list ensuring the install could be done as efficiently as possible. Jovanis also enlisted the help of Troy Baum of Race Wires to further assist with the installation. Baum’s shop was responsible for Jovanis’ Elite 2500T conversion four years ago and Baum’s never-ending knowledge was a huge benefit. We also tapped Scott Triolo for his meticulous wiring skills and speedy work ethic.
A nice touch when working with Haltech products is the company’s tech support, which is only a phone call away. Haltech also provided wiring diagrams, sensors, and various electrical connectors to make the garage-based project smooth and organized. A little-known fact about the helpline, the company transfers all after-hour calls to California or Australia so your late nights in the garage are met with someone on the other end. Over the years the Australian tech team has been a reliable asset for Jovanis, as he works late in the office and spends time with his family before moving into the garage to work on the Mustang.
For our tech shoot, Jovanis made our lives even easier with his vigorous prep work before Baum, Triolo, and the Race Pages staff swooped in for this conversion. He removed the dashboard, then labeled and organized all of the parts, pieces, and diagrams before work began promptly at 8 a.m. The wiring was completed by dinnertime with three people hammering away on it. Jovanis handled the PDM programming on his own, which went well into the evening. Haltech’s after-hours tech line signed into his laptop remotely to finalize the configuration and Jovanis fired the car up on the first turn of the ignition key.
A week after the conversion Jovanis dragged the car over to a chassis dyno and then stopped at Atco Raceway to ensure all systems were functioning properly. The team made a few easy pulls at just 20 psi of boost to ensure the tune and boost controller functions transferred over cleanly. It produced a paltry 1,200 rear-wheel horsepower without any effort. On track, a best of 7.64 at 181 mph during test and tune was deemed a success given the track, weather, and low-boost strategy.
Stepping up to the Nexus R5 is all about combining the vehicle’s functions into a single unit—simplifying wiring for reliability, giving more control over various electronic tasks like turning on fans or boost controllers under specific commands, and bringing it all together in a common software layout. That eliminated the Haltech relay box and two large—and costly—solid-state relays. Right now, the Nexus R5 controls four 25-amp and 12 8-amp functions that span from traction control to blinker lights in this bonafide 7-second street machine.
In addition to all of the benefits of the Nexus R5’s expanded capabilities, this upgrade also gives you the foundation to continue expanding engine-management strategies with software based changes and upgrades instead of adding boxes and relays along with pulling wires through the vehicle. The flexibility, data analysis, and expanded capabilities are also a welcome change for Jovanis, who recently ditched the 8.2-deck engine in favor of a new DiSomma Racing 423ci small-block as he looks to continually push his 1989 Mustang deeper into the sevens in 2021 and beyond.
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