In motorsports, we focus on three fundamental actions: accelerating, turning, and braking. The way we combine these elements determines our ultimate lap time. To optimize performance, it’s essential to analyze these driver inputs alongside other critical data such as speed and position.

Vehicle Connectivity Options

In the early days of motorsports, data collection required dedicated sensors and analog inputs, all of which were part of expensive and complex data logging systems. Installing and configuring these systems often required an engineer.

Today, modern vehicles come equipped from the factory with a wide array of sensors designed to monitor both driver inputs and vehicle health. However, accessing and utilizing these signals for motorsports applications can be challenging.

The OBD II Standard

Since 1996, all vehicles sold in the United States have been required to include a standardized onboard diagnostics connector, known as the OBD II port. This port is typically located beneath the driver’s side dashboard.

OBD II was originally designed to facilitate communication with a vehicle’s engine control unit (ECU) for diagnosing emissions and performance-related issues. Automotive service tools use OBD II to retrieve and clear diagnostic trouble codes (DTCs) and monitor key engine parameters.

OBD II PIDs (Parameter IDs)

In real-time data monitoring, each sensor reading is associated with a unique PID (Parameter ID), which allows diagnostic tools to request specific sensor values. This structured approach is necessary because early OBD II protocols had significant speed limitations.

Using OBD II for Motorsports

While OBD II provides access to some useful data, it has limitations for motorsports applications. Available performance-related PIDs include:

  • Throttle position (throttle plate or accelerator pedal position)
  • Engine speed (RPM)
  • Engine coolant temperature
  • Oil temperature (available on some vehicles)

However, OBD II does not provide access to critical driver input data such as steering angle or brake pressure, which are essential for in-depth motorsports analysis.

OBD II and CAN Bus

Since 2008, all U.S. vehicles have been required to support OBD II functionality using a diagnostic CAN (Controller Area Network) bus, accessible via pins 6 and 14 on the OBD II connector.

This CAN-based protocol enables faster data retrieval compared to older OBD II implementations. However, it still requires a scan tool to actively request each PID, making it less efficient for high-speed data logging.

Diagnostic CAN Bus Limitations

While some vehicles broadcast additional CAN signals on the diagnostic bus, manufacturers often restrict this data. Common limitations include:

  • Low update rates: The refresh rate may be too slow for motorsports applications.
  • Limited data availability: Some critical performance signals are not broadcast on the diagnostic CAN bus.

Capturing Diagnostic CAN Bus Signals

For vehicles that do broadcast useful CAN signals on the diagnostic bus, logging data is relatively simple:

  1. Connect a data logger to the OBD II port.
  2. Intercept CAN messages to extract relevant sensor data.
  3. Map the signals to logger channels using software such as SoloStorm or CircuitStorm.

Signal mapping can be configured manually or by selecting a preconfigured setup from the Vehicle CAN Library.

Understanding Vehicle CAN Bus Networks

Modern vehicles use multiple CAN buses for different functional areas, such as:

  • Powertrain CAN (PT CAN or Drive CAN) – Engine, transmission, and drivetrain controls.
  • Chassis CAN – Steering, braking, and suspension systems.
  • Comfort CAN – Climate control, lighting, and infotainment.
  • Safety CAN – Airbags, ABS, and stability control.

In motorsports applications, the powertrain CAN bus is often the most useful, as it provides access to critical driver input signals.

The Role of the CAN Gateway

Vehicles with multiple CAN buses rely on a CAN gateway to facilitate communication between different systems. For example, the powertrain CAN bus may receive steering angle and brake pressure data from the chassis CAN bus to support traction control.

Because certain signals are shared across buses, tapping into the powertrain CAN bus is a common method for retrieving motorsports-relevant data.

Capturing Powertrain CAN Bus Signals

To access powertrain CAN bus data, you will need to physically tap into the CAN wiring. The key steps include:

  1. Locate the CAN High (CANH) and CAN Low (CANL) wires in the vehicle harness.
  2. Use a dedicated OBD connector for data logging. This prevents interference with the factory OBD II system.
  3. Connect a data logger or scan tool such as:

Wiring Location and Color Codes

Whenever possible, the necessary CAN bus and power wire locations, colors, and pins are provided in the Vehicle CAN Library.

  • When working with vehicle wiring, it is crucial to verify all wire colors and pin locations using manufacturer-provided information.
  • You are solely responsible for correctly modifying your vehicle’s wiring if necessary. Petrel Data Systems assumes no responsibility for any modifications you make.
  • While any wiring information provided has been verified to the best of our knowledge, you must independently confirm its accuracy.

Locating Powertain CAN Bus Wiring

CAN bus wires are always twisted pairs to reduce electrical interference, making them easy to identify in the vehicle harness. The best locations to tap into these wires include:

  • At the CAN bus gateway
  • Near an ECU or module that communicates across multiple buses

When tapping into vehicle wiring, always verify the wire colors and pin locations using manufacturer-provided schematics.

Power and Ground Conections for Data Loggers

Most CAN-based loggers require a 12V power source and a reliable ground connection. You can:

  • Tap into an existing fuse location using a special fuse tap.
  • Connect the ground wire directly to the chassis.

We strongly recommend adding a 1A fuse to the power wire on any data logger.

Configuring SoloStorm and CircuitStorm

To set up CAN data logging in SoloStorm or CircuitStorm, follow these steps:

  1. Using an OBDLink Scan Tool

  2. Manually Configuring CAN Signals

By properly tapping into and configuring your vehicle’s CAN bus, you can unlock valuable data for motorsports analysis—helping you refine your driving techniques and optimize your performance on the track.