Telemetry shows what you and the car did at every point on the lap: speed, throttle, brake, steering, gear and more, plotted against distance. To find time, overlay your lap on a faster one and look at three places in each corner: where braking starts and how it is released, the minimum speed, and when the throttle goes back down. A time-variance (delta) plot shows exactly where the gap opens.
Where the data comes from
Most simulators record telemetry you can open in analysis software. Assetto Corsa includes setup options and telemetry for data analysis (Steam). For iRacing, Cosworth, an official iRacing data analysis partner, offers its Pi Toolbox, which the announcement says is used in Formula 1, IndyCar, WEC and WRC (iRacing). MoTeC's i2 software, developed with input from professional race teams, is another common choice (MoTeC).
The channels to start with
| Channel | What it tells you |
|---|---|
| Speed | Where you are fast or slow; the lowest point in each corner is your minimum speed |
| Brake | Braking point, peak pressure and how gradually you release it into the corner |
| Throttle | When and how decisively you get back to full power |
| Steering | Corrections and how much lock you need, which hints at understeer or oversteer |
| Gear and RPM | Shift points and whether you are in the right gear for each corner |
| Time variance (delta) | Where time is gained or lost between two laps |
MoTeC describes its Time Variance Plot as a quick view of where time has been gained or lost between laps, and supports overlaying laps from different sessions or drivers (MoTeC).
How to read a comparison
- Pick a reference lap from a faster driver in the same car and track. The Virtual Racing School's data packs bundle a hotlap replay, setups and telemetry for exactly this (VRS).
- Find the biggest jump in the delta. Fix the corner costing the most time first.
- Compare the brake traces. Look at where braking starts, how high the peak is and how pressure trails off. The Skip Barber Racing School notes that drivers' brake-pressure graphs most often show a steady release from turn-in toward the apex (Going Faster! excerpt, Bentley Publishers).
- Compare minimum speed. A lower minimum usually means you over-slowed or took a tighter line.
- Compare throttle pickup. In an iRacing column, an engineer overlays two drivers' throttle and brake against speed and shows the faster driver going deeper into turn one and getting back on the throttle sooner and without hesitation (iRacing).
Use the friction circle
Plotting lateral G against longitudinal G shows how much of the tires' grip you use. Skip Barber notes that real-car data systems can draw this friction circle from a lap (Bentley Publishers). The goal, as the Virtual Racing School puts it, is to operate as close to the edge of that circle as possible, so gaps in the plot, for example between braking and cornering, show where grip is going unused.
Know what you are looking for
The same iRacing column warns that telemetry is a diagnostic tool, not a setup guide. Its author says the most important thing is to know what you are looking for before opening a log file, and that telemetry should confirm what the driver feels rather than replace it (iRacing). VRS gives similar advice: get your laps consistent first, because data from inconsistent laps is not reliable feedback (VRS).
Common mistakes
- Comparing laps in different cars, setups or track conditions.
- Looking at whole-lap averages instead of individual corners.
- Changing the setup before the driving is consistent.
- Copying a reference driver's brake point without matching their release and line.
Pair this with how to improve your lap times and understanding racing lines.
Leaderboards at events
At an event, a live leaderboard does a simple version of the same job by showing who is fastest and by how much. SimsForHire brings racing simulators to corporate events, private parties, trade shows and brand activations; see case studies and pricing ($2,750 per full-motion rig per day, plus tax and insurance), or call (754) 228-5654.