What an override is for
Normally a nitrous stage on an Elite only turns on when its activation conditions and mode say it should. An override skips all of that and switches the stage on directly. There are two common reasons to want that:
- Purging: often called burping. You briefly open the nitrous solenoid (usually a purge valve) to push gaseous nitrous out of the feed line, so the first hit of the pass gets liquid instead of a lean puff of gas.
- Manual activation: a driver who wants a button that fires the stage when they decide.
Because an override bypasses your normal safeguards, the lockouts on the Settings tab matter more here than almost anywhere else in the nitrous setup.
Triggering the override
On the Wiring tab, Switch Enable decides whether a physical input fires the override. Leave it unticked and you can use the conditional activation option on the Settings tab instead, or combine the two.
SPI input
- Edge Select: Falling when the button grounds the input, Rising when the button supplies voltage.
- Sensor Type: Hall Effect for any switch.
- Pullup: turn on when the input needs to be held at a voltage while the button is released, typical with a ground-switching button.
AVI input
An AVI (analog voltage input) needs an on voltage and an off voltage. Leave room between them so noise can't toggle the stage. If a grounding button pulls a 5V input down to near 0V, setting on below 0.5V and off above 4.5V gives a clean switch with margin for noise. If your button takes the input up to 12V from about 2.5V at rest, put the on point well above resting voltage and the off point in between.
Settings tab lockouts
| Setting | What it does | Our advice |
|---|---|---|
| Minimum Engine Running Time | The engine must have been running at least this long before the override can fire | Keeps a stray button press during cranking from doing anything |
| Minimum TPS | Throttle must be at or above this value | For a purge-only setup, keep it low. For a power stage, require real throttle |
| Minimum RPM | Engine speed must be at or above this value | For a power stage, set it high enough to keep nitrous away from low RPM |
| Conditional Activation | Fires the override when ECU conditions are met, with or without the switch | Useful for things like "only with the arm switch on" |
If the override only drives a purge valve, the solenoid is venting to atmosphere and you want it usable in the staging lanes at idle or low throttle. If the override drives a stage that feeds the engine, treat it like any other nitrous stage: high TPS, safe RPM, fuel pressure confirmed. Never use a low-lockout override on a stage that feeds the engine.
How we wire and test it
- Wire the button to a spare SPI or AVI and confirm the input changes state in the ECU's channel view before you connect any solenoid.
- Set the lockouts, then test the output with the bottle closed. You should hear the solenoid click only when every condition is met.
- Open the bottle and check for leaks before trying a real purge.
- Log the override state with fuel pressure and lambda during your first passes.
For the relay side of the job, see nitrous relay wiring for multistage systems. A nitrous pressure sensor set up as a nitrous pressure input lets you confirm bottle pressure too. For a broader look at how the ECU manages a system, read ECU controlled nitrous injection and nitrous, the forgotten power adder.
FAQ
Does the override ignore my fuel enrichment?
The override changes when the stage turns on, not how the stage is tuned. Your fuel and timing corrections for that stage should still be set properly, so check them before using it.
Can I purge without a switch?
Yes. Leave Switch Enable off and use conditional activation, though most racers prefer a button so they control exactly when it happens.
