Apex Lab motorsport telemetry logoAPEX LAB

guide · 8 min read

Race car data analysis: a practical telemetry guide

You don't need a professional engineer to read race car data. With a cheap GPS logger and the right mental model, you can turn telemetry into measurable lap-time gains. This guide walks through the four traces that matter most — speed, G-force, throttle and brake — and how to spot the patterns that separate a good lap from a great one.

1. The speed trace

The speed trace is the foundation of every telemetry session. Overlay your best lap on a reference lap (your previous best or a faster driver in the same car) and look for three patterns:

  • Min-corner speed gaps. Where your line bottoms out lower than the reference, you're either braking too hard, turning in too early, or carrying the wrong attitude into the apex.
  • Late acceleration. If the trace climbs slower out of a corner, you're getting on throttle late or the car is pushing — check throttle and steering overlays.
  • Top-speed deltas on straights. Almost always a corner-exit problem, not a power problem. Walk the trace back to where the gap opened.

2. G-force traces

Lateral and longitudinal G tell you how hard the car is working. Two rules of thumb:

  • Combined G should be smooth. Sharp spikes between braking and cornering mean you're trail-braking poorly — releasing brake before initiating turn-in instead of bleeding off pressure as load transfers.
  • Peak lateral G is car-limited. If you're not within ~0.1 G of the best lap's peak, you're not loading the tire. Often a confidence problem, not a setup one.

3. Brake and throttle traces

The throttle and brake traces show intent. The two questions to ask every corner:

  • How quickly does brake pressure rise? Fast initial application, progressive release. A slow ramp wastes braking distance; a flat plateau means you're not modulating.
  • Where does throttle pick up? Pin the throttle trace against the speed trace — if speed rises 50 ms before throttle, you're coasting through the apex.

From data to lap time

The trap is staring at traces. The fix is to pick one corner per session — the biggest single time loss vs your reference — and run three laps focused only on that change. Re-export, compare, and confirm the gain before moving on. That's the loop a professional engineer runs, and it works with a $50 GPS logger.

APEX LAB automates the comparison: upload a GPX or VBO file, pick a reference lap, and the app surfaces the corner where you're losing the most time and why. Plus rulebook-aware setup advice if you want to take the next step.