Why use a load cell?
A load cell (or shift force sensor) sits in the gear lever and outputs a voltage that changes with how hard the driver is pushing or pulling. Unlike a simple shift switch, it reads both directions from one sensor. That lets Flat Shift tell an up shift from a down shift, cutting power on the way up and blipping the throttle on the way down.
The Load Cell settings only appear in NSP once Trigger Options > Input Select in the Flat Shift function is set to Load Cell. Wiring is covered in Flat Shift wiring.
The two settings, in each direction
There are matching sets of settings for up shift and down shift:
| Setting | What it means | Our advice |
|---|---|---|
| Voltage | The load cell voltage the ECU sees when the lever is pushed into that shift direction | Always calibrate it on the car, never type in a guess |
| Hysteresis | How far the voltage has to move away from the calibrated value before the ECU decides the lever is back at rest, or outside the expected range | Start at half the gap between the rest voltage and that shift's calibrated voltage |
Calibrating
- Reset the ECU so the new input selection is active.
- Open the Flat Shift function again.
- Push the lever firmly in the up shift direction, as you would when shifting, and click Calibrate for the up shift. The measured voltage fills in automatically.
- Pull the lever in the down shift direction and click Calibrate for the down shift.
- Note the rest voltage with your hand off the lever. You'll need it to set hysteresis.
Worked example
Say the lever rests at 2.5V, a firm up shift reads 3.5V and a firm down shift reads 1.5V. The gap on each side is 1.0V, so a starting hysteresis of 0.5V for both directions makes sense. A reading has to move clearly toward rest before the ECU considers the shift finished, and small wobbles from vibration or a light hand on the lever don't count.
With the engine off, watch the load cell voltage and flat shift status in NSP while you rest your hand on the lever, tap it lightly, rock the car on its suspension, and then make real shift motions. Only the real shifts should register.
Troubleshooting
| Symptom | Usually |
|---|---|
| Cuts when resting a hand on the lever | Calibrated with too light a push, or hysteresis too small |
| Some shifts don't trigger | Calibrated with too hard a push, so normal shifts never reach it |
| Up and down shifts swapped | Calibrated with the lever moved the wrong way for each direction. Recalibrate both |
| Settings missing in NSP | Input Select isn't set to Load Cell |
Once it triggers reliably, tune the actual shift with ignition retard, recovery time and throttle blip amount.
