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A data channel that records how far the throttle pedal is depressed, expressed as a percentage from 0 (fully off-throttle) to 100 (wide-open throttle). It is one of the six foundational telemetry channels — alongside speed, engine RPM, steering angle, and lateral/longitudinal acceleration — and one of the most important for diagnosing both driver technique and chassis behavior. The throttle trace is most powerful when overlaid with speed, brake pressure, and steering angle: in isolation it is relatively plain; in context it reveals coasting gaps, hesitant application, premature lift at corner exits, and stabbing inputs that unsettle weight transfer.
Segers' Analysis Techniques for Racecar Data Acquisition defines the channel directly: 'The throttle position signal measures what the driver is doing with his right foot on the accelerator pedal.' He describes the coasting detection formula — coasting is identified when throttle position is below 5% and brake pressure is below 5 bar simultaneously — making the channel indispensable for quantifying time lost between the brakes and the gas. Segers also introduces the throttle histogram, a statistical distribution of how much lap time a driver spends at each throttle-position bin. The ideal histogram is heavily weighted toward the full-throttle bin with minimal dwell at part-throttle positions; a faster driver will show a taller full-throttle bar and lower partial-throttle bars, while a hesitant driver will spread time across the middle bins. In a documented two-driver comparison, Driver A was 2 seconds per lap quicker than Driver B, and the histogram showed Driver A treating the throttle as more of an on/off input while Driver B's higher part-throttle bins revealed tap-dancing on the pedal.
From an HPDE technique standpoint, the throttle trace exposes the most common novice error: stabbing the throttle. Treating the gas pedal as an on/off switch — jumping from coasting or maintenance throttle straight to 100% — causes wheelspin, sudden understeer, and rear-weight shifts that unsettle the chassis. The correct technique is a progressive squeeze to full throttle at corner exit, beginning only after steering angle starts to unwind. Because the traction circle limits how much grip can be divided between cornering and acceleration simultaneously, any throttle applied while steering lock remains must be proportional — adding throttle too early pinches the car to the inside, while a smooth ramp lets the front tires recover load as the wheel straightens.
The transition from brake release to throttle application is equally diagnostic. It must be seamless: the driver should never feel the precise moment of transition, and there should be no detectable coasting gap between releasing the brake and picking up the throttle. Data coaches use the throttle trace side-by-side with the brake pressure trace to measure this gap directly. A coaching session comparing a reference instructor lap to a student lap will show the instructor's throttle pickup beginning earlier and ramping smoothly, while the student's trace often shows a flat coast region followed by an abrupt step.
On multi-channel displays, throttle position is typically shown as a bar-graph or percentage trace alongside GPS speed, brake pressure, and steering angle. Time-based and distance-based views both serve different purposes: time-based views preserve the actual duration of coasting gaps; distance-based views let coaches annotate specific track segments and corners. Throttle histograms from two-lap overlays — for example, a warm-up lap versus a fastest lap, or a reference driver versus a coached driver — remain one of the most communication-efficient tools in a post-session debrief because the improvement target (raise the full-throttle bin, collapse the partial-throttle bins) is immediately visible.