Project Red Dragon started out as a simple bolt-on F-body, and has now become so much more. To really harness all of the Pontiac Trans Am’s potential at the track, we decided it was time to move on from the OEM ECU. So we talked with our friends at Haltech and discovered the Haltech Nexus R3 VCU would be perfect for our application.

Haltech offers a wide range of vehicle ECUs and VCUs that can run literally anything with an engine. VCU stands for Vehicle Control Unit, which according to Haltech, is a unit that can do more than just control the engine. The Nexus R3 is the evolution of Haltech’s 2500 line of ECUs and falls nicely behind its flagship Nexus R5 VCU. The R3 works out great for a build like Project Red Dragon, since it’s not an overly complex race car, but still needs plenty of inputs, outputs, and advanced data-logging that the OEM ECU can’t offer.

The R3 Explained

Haltech designed the R3 to be a versatile VCU that could do a lot in a simple package. That’s one of the big upsides the R3 brings to the table: its ability to integrate into a vehicle that has existing systems that are already being used.

Haltech’s Andrew DiMartino explains how the R3 can be used with systems your vehicle already has in place.

“The R3 is a great fit when you’re looking for something that has the chassis wiring all handled by standard relays or what came in the car before it became a race car. The R3 has an onboard Power Distribution Module (PDM) that can drive your coils and injectors, and actually power them without a relay. You will still have two additional 25-amp drivers that can be used for other functions.”

If you’re running a turbocharged combination like we are with Project Red Dragon, the R3 has a built-in single wideband that can run a Bosch 4.9 oxygen sensor. The onboard unit can also run an NTK sensor if you’re running a methanol-fed combination.

Let’s say you’re running a naturally aspirated, nitrous, or supercharged combination; can you run a second wideband with the R3? Absolutely. You would just add a second wideband via the CAN network used by the Haltech system.

The R3 borrows a nice feature from its big brother, the R5, and that’s Wi-Fi capabilities. This provides users with more opportunities to make adjustments and makes the tuning process easier.

“With the Wi-Fi, once everything’s set up you don’t need cables to pull data logs, to tune your car live, or even have one of your guys make a change when you’re pulling back into the pits. If you have a crew chief that does all your tuning, you pull up to the pits, it automatically connects, and it can download your data-log from your last run,” DiMartino says.

Haltech has a great breakdown of the R3’s tech specs you can check out right here. This goes into great detail about everything the VCU offers on a technical level.

Comparing The R3 To The 2500 And R5

Haltech’s 2500 ECU has been a workhorse for many years, and it can run all kinds of engine combinations. When you look at the R3 compared to the 2500, you can see why it is considered its successor. The R3 offers added functionality like additional drivers, built-in Power Distribution Module, more inputs, more outputs, and the ability to run certain vehicle functions.

“The R3 gives you all of the Nexus’ functionality. You’re upgrading from technology that was great technology, but that was eight or nine years ago. Now you’re going into Nexus technology, which is a faster ECU, it’s a faster processor, and it has a lot more features. It really speeds stuff up,” DiMartino says.

Now, the R5 is a very robust and advanced VCU that can literally run an entire car and all of its functions. According to DiMartino, it’s the go-to ECU for advanced, full-on race car builds.

“If you have a full-on race car and you have headlights, brake lights, and turn signals, the R5 will be your one-stop shop when it comes to wiring the chassis, as well. The R5 gives you the works. The R5 has as many inputs and outputs as you can probably imagine and get creative using. When it comes to a pro-level race car, it fits the bill perfectly.”

• 
• 

The R3's built in PDM capabilities make it a solid step up from the Elite 2500.

The R3 is perfect for those who need something with more functionality than the 2500 ECU, but don’t need all the R5’s features. It’s really geared towards a car that’s transitioning from your typical weekend warrior street car to a proper race car.

A bracket racer who wants to move to EFI can easily take advantage of the features offered by the R3, too. The R3 has different timers the user can configure to run different functions, including air shifters and other driver aids. Bracket racers can also use the R3’s robust data-logging and tuning functions to improve the consistency of their race car.

Flexible Tuning Options

Race cars come in all shapes and sizes, so there needs to be some flexibility with how you can tune them. The R3’s Nexus software doesn’t have a rigid system that limits how you can set up functions of the VCU. There’s plenty of flexibility built into every tuning aspect available on the R3.

Let’s look at transmissions. If you’re going to use an electronically controlled transmission, the R3 has native transmission controls built-in. That means you can manipulate line pressure, shift points, and other transmission functions without needing an additional transmission controller.

If you plan on running both traditional pump gas and E85, the R3 has built-in flex-fuel tuning options. This flexible tuning option can be activated by wiring in a flex-fuel sensor into the wiring harness and ECU. The R3 will then look at the information provided by the flex-fuel sensor and make sure the correct tune is being used for the fuel it sees. This is done through the 4D tuning table you can create inside the Nexus software.

Chris Law explains how the flex-fuel 4D tables work.

“You have your X and your Y on your table. That’s your second and third axis. The table itself, whatever the value is, that table is always the first axis because you would have a single cell that’s a one-axis table. Then you add an X axis and a Y axis, and those are your second and third. What we do is allow you to have up to 12 different layers to that table as well in the 4D, so that adds a fourth dimension. Most often that’s used for some switched input, the little rotary knobs or our keypads, to have multiple tables or boost control or the torque management curve or just an ignition curve for an actually aspirated car.”

The R3s Live Tuning Abilities.

Aftermarket EFI systems have come a long way since they were first introduced to the high-performance arena. Gone are the days of “burning a chip” for a tune and hoping the calibration was sort of correct. VCUs like the R3 give users the ability to make real-time changes to a tune while the vehicle is running.

“With the live tuning, you’re making changes in real-time. As you make them — as you see them, they’re actually happening. It offers a really quick way to tune the vehicle. You’re not having to flash a tune each time you make a change. Anything you’re doing, it’s actually writing to the ECU at the same time,” DiMartino states.

• 
• 

You can make adjustments to your tune as the vehicle is running with the R3's live tuning features.

Let’s say you’re getting ready to make a pass and there’s an oil down, the air gets better, or some other big change occurs. The live tuning feature offered by the R3 allows you to make changes on the spot via different methods.

“If you have the laptop out, you can make changes, especially if you have someone hooked up to your Wi-Fi, like your crew chief or something like that. Now, if you are the driver and tuner, you can use a keypad or rotary trim switch to make an adjustment to the tune on the spot. You can make adjustments to your timing or boost curve, change your launch RPM, or any other defined change you’ve set up in the system,” DiMartino says.

Now, there are some adjustments that would require you to key-over for and turn the ECU off and then back on. These are things that go beyond what you would expect in a live-tuning situation and are usually pretty extreme.

“If you wanted to change the entire fuel table 10 percent, that doesn’t require a key-on change or anything like that. Even though it’s a pretty big sweeping change, that’s part of tuning. I would say that the “live tuning” covers every single bit of changes to tables and their values. However, parameters that require a key-over reset to change include the foundational setup or configuration such as cylinder count, firing order, and enabling/disabling functions. These are parameters that alter how the ECU understands and interprets its inputs and how it controls its outputs,” Law explains.

R3 Data Logging And Diagnostics

You truly can’t put a value or price on data when you’re trying to optimize the performance of a vehicle. Good data will tell you what you’re doing right and wrong. This gives you the ability to make the correct adjustments. The R3 has the capacity to store 128 megabytes of logging data (or about a day’s worth of runs, roughly) onboard through loop logging. What that means is the data will start to overwrite if you forget to clear it or download it once the 128 megabytes is filled up.

The R3’s data logging functions can be turned on manually by the driver via a keypad button. Data logging can also be turned on automatically when the R3 sees a certain percentage of throttle input, or after a button, like the transbrake, has been released. You can set the data logging to run for a specific amount of time to save space as well.

There’s an astounding amount of data channels that you can watch with the R3. You can easily overwhelm yourself if you’re not careful, but there’s more to the data logging abilities of the R3 than the volume it can sample. The R3 can sample data at a high rate and that provides you with an elevated level of accuracy.

“One of the biggest things about the Nexus is how fast everything is. The amount of speed that you can data log some of these channels is almost faster than you can comprehend. A lot of times we are actually slowing data down to figure out what the car did. That’s one thing that’s really helpful. It’s just like watching a slow-motion camera. Your data log is high-speed. You can slow it down because you’ve got a lot of resolution. That’s a big thing with the onboard data logging,” DiMartino says.

The onboard diagnostic abilities of the R3 can make troubleshooting problems much easier. You don’t have to pull out the multimeter right away thanks to the tools within the software, you just need to pull out your laptop to start the diagnostic process.

“We’ve all had issues trying to get an engine to crank over and we’re not sure what’s causing the problem. You can actually pull all of this data up and watch your oscilloscope to watch the pulses of different things. With the R3 also having a PDM, you’ll have some actual electrical system diagnostics when it comes to amperage draw and voltage directly to your pumps or your ignition coils, or your injectors themselves,” DiMartino states.

• 
• 

As you can see, there's a lot going on under the hood of the Red Dragon. We needed the ability to accurately monitor and control different systems, so the R3 just made sense.

To take things a step further, DiMartino presents an example of how these diagnostic functions can be used.

“If for some reason you have a coil that’s shorted out and it keeps tripping an over current, you can actually see that it is in fact the coils that are “blowing” the fuse even though you have no fuses. You can see also if you’ve got a fuel pump that would normally be pulling 15 amps and all of a sudden, it’s pulling 25. That will tell you this pump is probably on its last leg, so if something happens, we know that we need to have another pump.  For me, the biggest advantage of the R3  is going to be the ‘scope and all of your PDM diagnostics.”

The Haltech Nexus R3 is a big step up from the OEM ECU and we’ve got a pretty steep learning curve in front of us. Project Red Dragon will really benefit from all the features the R3 offers. This is just part one in our series of Haltech upgrades to the Trans Am. In the next part, we’ll show you how to build a custom wiring harness for a standalone VCU like the R3. Finally, we’ll tie everything together with one of Haltech’s IC7 dashes and CAN keypads.

Make sure you check out the Project Red Dragon page on Dragzine right here to see what we’ve done to the car and how it’s performing at the track.