When you consider a car like the Nissan GT-R, you have to know in advance that complexity is part of the equation. We are, after all, talking about twin-turbo, all-wheel drive supercar, with a dual-clutch transmission and a factory electronics system designed to keep the car approachable for “drivers of all levels,” according to Nissan.
When you outfit a Nissan GT-R for racing, the complexity rises exponentially and increases the challenges normally associated with converting a production car to a racecar. Valkyrie Autosport’s Brian Lock took on the task, and we’ve highlighted the challenges of the chassis and suspension in past issues of Speed News. In this installment, we’re going to attempt to unpack how Lock and his team handled the electronics packages they used to convert the GT-R for racing, a series of convoluted and challenging tasks Lock called “super nerdy fun.”
The team started with the Cobb Tuning module for altering different maps on the car, and it worked well when the team raced in E0 class, but when the team moved to ES, it became clear they needed to do more — a lot more. That ushered in the addition of a MoTec Race Grade multifunction steering wheel, a MoTec PDM15 power distribution module and a MoTec M150 ECU.
Getting these three components to work in harmony was critically important for ease of operation. This being an endurance car, drivers have to be able to jump in, understand how everything works and still drive it like gangbusters, and the key component of the driver interface was the steering wheel.
“Everything was now able to be controlled by the steering wheel directly whereas before if you needed to do something, particularly with the access port, you need to plug in a laptop to the access port and make a change,” Lock said. “Now we can just do everything essentially with one device from the steering wheel.”
Factory Wiring Harness
Lock had gone through the trouble and expense of having a custom wiring harness made for the GT-R’s sister car, a Nissan 370Z. The team didn’t really have the time, nor did it have the budget to do the same thing with the GT-R, and Lock wanted to keep the factory wiring intact for reliability purposes.
“Factory wiring harnesses are typically very robust,” Lock said. “These connectors and everything were designed to last, obviously the life of the vehicle. So it made the upgrade very quick to do, more cost effective to do, and you’re not introducing any reliability issues from custom parts on the car.”
Luckily MoTec makes an “adapter box,” so Lock could use the factory wiring harnesses and M150 engine management system. The factory harness connects to the adapter box and it connects to the ECU. The programming that allows the factory-wired components to send and receive signals from the ECU was all done in house by MoTec in Australia. All Lock had to do was connect the harnesses from Nissan and MoTec.
“And what was cool about this, obviously, was the body control module, the factory body control module on the GT-R that controls all sorts of things was now fully integrated into the MoTeC system,” Lock said.
MoTec ECU
That same high level of programming also is present in the base tables done by MoTec for the Nissan GT-R. So when Lock bought the M150, it was already loaded with the maps. In addition, the M150 also controls the distribution of engine power to the rear and front axles.
“Now there’s a little table when you open up the software that says, ‘OK, how much front wheel drive do you want under what conditions?’” Lock said. “And you enter those conditions, but we don’t have to do the really hard work of deciphering that ourselves after we buy the M150. That’s all done for us.”
Again, because of the adapter box, the M150 could process all the signals to and from the engine via the factory Nissan wiring harness, but it also communicates with and can be adjusted from the Race Grade steering wheel.
“Once we upgraded the system with the PDM15 and the M150, we changed some of the programming of those buttons on the steering wheel, because we were able to control things like all-wheel drive on the steering wheel, which we weren’t before,” Lock said.
MoTec Steering Wheel
With the MoTec wheel, which is fitted with 14 buttons, four rotary switches, shift paddles and lights, and a display screen, drivers were able to make all kinds of adjustments and take in all manner of relevant information.
One of those rotary switches gave the driver direct control over how much front-wheel drive the car used, which was especially handy during the 2019 25 Hours of Thunderhill because of rainy conditions that endured throughout the race.
Lock said the wheel was instrumental to allowing team drivers to focus on driving, as well as giving them fast access to controls for wipers, push-to-pass lights and traction control. Lock also customized the display to provide drivers with information they needed while excluding what they did not. There’s even a button to toggle between different “pages” of information displayed on the screen.
“They’re just waiting for those shift lights to light up and then they pull the paddle,” Lock said. “There’s basic engine vitals, engine temperature, oil temperature, oil pressure, and then we had a fuel-use counter to give them a sense of how much longer they were going to be out there, especially when we upgraded to the 40-gallon fuel cell and that car.
Because the car can carry more than 40 gallons of fuel, driver stints tend to last a long time. The car could go 2.5 hours on a full tank in wet conditions.
Lock also repurposed a shift light module. Instead of having a program with engine RPM, he programmed it to respond to brake pressure. It would light up as the brake pressure approaches the optimal range, then change colors if drivers exceeded those values. It allowed the team to preserve the braking system during the 25-hour race.
“The dash display itself actually is not that complex, and we don’t really want a ton of information displayed on it, because all it’s really going to do is distract the driver,” Lock said.
MoTec Power Distribution Module
A key to getting all the electronics to cooperate was the MoTec PDM15, a solid state, 15-channel programmable power distribution module and relay box that allows the user to program logic into each of the 15 channels.
The PDM15 takes signals and inputs from the steering wheel, the factory ECU, any combination of these inputs for different systems on the car. The headlights, for example, automatically turned off when car traveled at speeds below 25 miles an hour with the pit speed limiter.
“This is an example of everything being integrated. You press the pit-speed-limiter button, the ECU automatically cuts power to the engine until we reach 25 miles an hour,” Lock said, noting that there are black-flag penalties for exceeding the pit speed limit of 25 mph. “We had the headlights programmed to be on above 25 miles an hour, in case there was some sort of error with the system, it would give the driver a heads up, ‘Hey, I’m above 25 miles an hour, my headlights just turned on.’ Just an extra bit of awareness for the driver.”
Lock ran the wipers, headlights, cooling pumps and fans and anything that needed power that they wanted to control in a fashion greater than basic functionality. The car’s small Braille battery would drain quickly, so they programmed the car to turn off cooling pumps when needed. Sakata Motorsport Electronics in Anaheim, Calif., helped Lock get everything set up.
One-Way Telemetry
The steering wheel, ECU and power-distribution module allowed for one-way telemetry at Thunderhill, which is why Lock didn’t need to show the driver too much information. The crew could monitor anything they wanted from the pits. They could look at the data real time, and would know before the driver, if there was a problem. The team had one issue early on in the race and the telemetry pointed them in the right direction before the car ever entered pit lane.
The driver reported a loss of power. Telemetry showed they weren’t getting boost on one bank. Because the car has one turbo per bank, it was easy to spot in the data. It turned out an intake hose clamp on one of the throttle bodies had come loose.
“We knew exactly where to look,” Lock said. “So when the car came in, we were already prepped to pop the hood. We had the screwdriver out there, quickly put that pipe back on, and I think we had that fixed in under a minute.”
Another instance where telemetry paid dividends came when a driver reported a misfire. Turned out it wasn’t a misfire, but rather the traction control setting was too high for conditions. They could see it in the data from the pits. The driver dialed the setting down a bit and that solved the problem. No need to pit, and the driver made the adjustment on the steering wheel.
“So, really the telemetry is so fantastic for the for the car chief,” Lock said. “And I guess in a way it’s fantastic for the driver because they don’t need to worry about it, but it also is basically a constant tattletale. The driver is also constantly getting told on, and there’s nothing to hide when you’re driving the system like this.”
