02 Race Functions
Boost by gear
Target boost (and duty) per gear so first is driveable and fifth is the number you meant.
6 min readUpdated 2026-08
Boost-by-gear is a target (and usually a feed-forward duty) that changes with the gear the ECU thinks you are in. First and second get less boost so the tyres and the driveshaft survive; fourth and fifth get the full target. It is not a traction-control substitute, and it is only as good as gear detection.
How Race Core knows the gear
- Speed / RPM ratio. Needs a working VSS (Hall, VR, GPS pulse, or CAN speed) and a filled gear-ratio table. This is the usual race-car method.
- A dedicated gear-position sensor or sequential barrel switch on a digital / analog input.
- CAN gear from a dash or a gearbox controller, if that message is in the enabled CAN set.
Log “gear” next to VSS and RPM. If gear flickers 2–3–2 on a pull, the ratio table is wrong or the VSS is noisy — fix that before you trust a 0.4 bar step between gears.
What to fill in
| Table | Role |
|---|---|
| Target vs gear (and RPM / TPS) | The closed-loop boost target. First might be 0.8 bar, third 1.4, fifth 1.6. |
| Open-loop duty vs gear | Feed-forward. Closed loop cannot catch a 1 bar step if the duty table is still at the first-gear number. |
| Per-gear overboost cap | A hard cut a little above that gear’s target. One cap for all gears will either never trip in first or always trip in fifth. |
Tune
01Ratios
Drive each gear at a steady RPM, note VSS, fill the ratio table until logged gear is stable.
02Open loop per gear
Same method as Boost control, but one duty column per gear. Get close before you enable closed loop.
03Targets
Set first-gear target to what the tyre actually puts down, not what the turbo can make. Then step up.
04Hysteresis
A little hold so an upshift does not bounce the target mid-cut. Too much hold and you carry third-gear boost into fourth for a second.