The problem it solves
On a big turbo automatic, building boost on the starting line means loading the engine against the torque converter. In first gear, the combined multiplication of the converter and first gear ratio can be more than the brakes can hold, so the car creeps or pushes through the beams. A trans brake is the usual fix, but not every transmission has one.
Spool Up Gear takes a different approach. While you stage, the Nexus holds the transmission in a taller gear. With less torque multiplication at the wheels, the brakes can hold the car while the engine loads up and the turbo spools. When the conditions you set are no longer true, usually because you've let off the brake, the ECU commands a shift straight to first and the car leaves.
Only use Spool Up Gear if you really need it. Shifting into first with full launch boost on board is a huge shock load. Make sure the transmission, converter and driveline are built for it.
What you need
- Spool Up Gear Enable turned on in the Transmission Control function. The node doesn't appear until you do.
- A brake pedal switch or a brake pressure sensor, or both.
- A working vehicle speed input, see our vehicle speed guide.
- A throttle position sensor or drive by wire throttle.
The settings
| Setting | What it does | Our advice |
|---|---|---|
| Spool Up Gear | The gear held while staging | The lowest gear the brakes can reliably hold at your launch boost |
| Number of Conditions | How many channels (up to 3) are checked | Use all three for a tight definition of "staged" |
| Select | The ECU channel for each condition | Typically brake, vehicle speed and throttle |
| Maths | The comparison: equal, not equal, greater, less, greater or equal, less or equal | Match the logic you mean, for example speed equal to zero |
| Value | The number the channel is compared against | Set from your own logs, not guesses |
| Combiner | Links conditions so several must be true together | Use AND logic so a single channel can't trigger it on its own |
A typical staging definition looks like this: brake applied, vehicle speed zero, and throttle past a set opening. When any one of those stops being true, the transmission goes for first.
Things to know on the track
- When enabled, the spool-up conditions override everything else when the ECU decides which gear to be in.
- The shift to first isn't instant. Hydraulic delay in the transmission can add time before first engages, which shows up in your reaction time.
- Tune line pressure and accumulator back-pressure (if fitted) so that shift is as quick and consistent as possible.
Want a second opinion before you try it? Contact us and we'll look at your setup.
