Behind the scenes: SRT Viper GTS-R Data Engineers Tyler Hook and Chris Miller detail their responsibilities.
SRT Motorsports Data Engineers Tyler Hook (#93) and Chris Miller (#91)
- Q: Can you explain what you do on the race team as a Data Engineer?
- A: We have multiple roles. Our primary responsibilities are to run all of the data collection throughout each race weekend. In addition, we are also responsible for all of the electronics, wiring and timing stand operation - basically anything electronic or with a control strategy. During the race, the International Motor Sports Association requires us to continuously upload vehicle data to their network. We are in charge of this as well as the fueling strategy for the weekend.
- Q: What type of data do you collect on the race cars?
- A: Combined with the engine and the chassis, we log a total of around 400 different channels. Some of these are internal parameters within controllers. There are about 80 external sensors wired to the engine and chassis. We measure everything from engine temperatures and pressures to wheel speeds, suspension loads, hub accelerations, brake/tire temperatures, roll and yaw. We have 16 sensors just in the air conditioning system alone. Everything is recorded using on-board data loggers through a complex Controller Area Network. The CAN network allows us to send and receive data from the corners of the vehicle with single communication line, then split out to the individual sensors. This significantly reduced the weight of wiring and also allows you to communicate with all the various control modules. Most of the data is then downloaded when the car makes a pit stop, but we also have telemetry radios on the GTS-R that transmit data at all times when the car is on track. This is received at our timing stand - through the very tall antennas - and outputs on our monitors in pit lane. During a race, we monitor 86 channels on the car to continually watch the "health" of the car as well as the performance of the car during a lap.
- Q: How many control modules are on the GTS-R?
- A: The Video System Module, Data Logger, Engine Controller, Paddle Shift Controller, Power Control Module, Tire Pressure Monitor System, Telemetry Radio, CAN Switch Panel and Shift Light Controller are all onboard. There are no fuses or breakers on the car - it's all solid state and controlled by the PCM.
- Q: What electronic driver aids are on the GTS-R?
- A: The series only allows certain electronic aids for the driver. For instance, anti-lock brakes are not allowed. We are, however, allowed to have traction control, launch control, and shift control.
- Q: How does the shift control work?
- A: The transaxle is a dog-ring style, sequential gearbox. However, the only time the driver uses the clutch is during the launch from pit lane. All other times, the driver only uses the shift paddles located on the steering wheel. On upshift, the engine cuts for a split second (0.050 seconds to be exact). This is enough of a torque interruption to allow the gearbox to pop out of gear and engage the next gear. During this 50-millisecond cut, the shift actuator pre-loads the shift barrel on the gearbox, engine torque is reduced to a low level, the shift barrel moves to the next gear, then the engine torque is re-engaged in a controlled manner to reapply power. To the driver, it is instantaneous and he never lifts his foot off the gas. The downshifts are a little more involved. A similar strategy occurs, but after the shift barrel is pre-loaded, there is a "blipper" on the throttle that is engaged at the same moment the engine power is cut. The "blipper" opens the throttles to full open, then the engine controller turns the engine back on to create an RPM spike. This RPM spike generates enough torque impulse in the gearbox to knock the gearbox out of the current gear and into the lower gear. The timing of these events is very important, to make sure the RPM is matched and the torque to the rear wheels is smooth to not influence handling. Due to the increased complexity on the downshifts, it takes about 60 milliseconds. During this time, the driver does not touch the throttle until he is ready to re-accelerate - no "heel toe" needed.
- Q: Are there any specific challenges you will face on the data side at Baltimore?
- A: Yes. The telemetry and voice coverage is very difficult due to all the tall buildings surrounding the circuit. We will likely experience several cut-outs around the circuit due to interference. The chance of breaking sensors on the car is also much higher on a street course due to the rough conditions of the circuit.
Thank you for the time Chris and Tyler. Good Luck this weekend!