Coding a RaceCoach

By peterm95018, 4 July, 2026

RaceCoach

RaceCoach is a personal autocross telemetry and coaching project built to help me get faster between runs.

The goal is simple: after each run, RaceCoach should answer one question:

What is the one thing I should change on the next run?

This project started as a way to compare RaceChrono Pro data between runs. It has since evolved into a diagnosis-based coaching tool that looks at driving behavior rather than just reporting raw telemetry.

What RaceCoach Uses

RaceCoach currently works from RaceChrono Pro CSV exports, using data from:

  • RaceBox GPS
  • OBDLink vehicle data
  • RaceChrono Pro calculated channels
  • Throttle position when available
  • Segment definitions for each event

The data is uploaded from my iPhone or iPad to an Ubuntu server, where RaceCoach processes the run and publishes reports to the web.

What RaceCoach Looks For

RaceCoach compares a run against a reference lap and looks for patterns such as:

  • Late to power
  • Weak exit speed
  • Over-slowing
  • Momentum loss
  • Low-confidence timing differences
  • Execution errors such as lifting before the finish

The intent is not to overwhelm the driver with data. The intent is to translate telemetry into coaching language.

Instead of saying:

Throttle commitment was 0.32 seconds later after minimum speed.

RaceCoach should say:

You waited 0.32 seconds too long to get back to power. Commit to throttle as soon as the car is pointed.

Grid Report

The Grid Report is the short version meant to be read between autocross runs.

It focuses on:

  • One thing to remember
  • Diagnosis
  • Confidence
  • Evidence
  • What to do next run

View the current Grid Report:

RaceCoach Grid Report

Full Report

The full report includes more detail, including segment times, telemetry comparisons, gains, losses, and supporting metrics.

View the current Full Report:

RaceCoach Full Report

Why I Built It

Autocross happens quickly. There is often only a short amount of time between runs, and it is easy to chase the wrong thing.

RaceCoach is intended to help separate:

  • A real driving habit from a one-off mistake
  • A strong telemetry finding from a low-confidence result
  • A useful next-run adjustment from unnecessary over-analysis

The long-term goal is to turn RaceCoach into a driver development system that can track recurring habits over events and seasons.

Current Direction

The project is moving from telemetry reporting toward diagnosis-based coaching.

The current model is:

  1. Telemetry
  2. Metrics
  3. Diagnosis
  4. Coaching

The next step is to make the diagnosis engine smarter, especially around distinguishing entry mistakes, exit mistakes, over-driving, over-slowing, and momentum loss.

RaceCoach is still experimental, but it is already becoming a useful tool for reviewing runs and building a more disciplined approach to autocross improvement.


 

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