Why measure bottle pressure?
A nitrous jet only flows its rated amount at the bottle pressure it was sized for. Let the bottle get cold and pressure drops, the engine gets less nitrous than the fuel was tuned for, and the mixture goes rich. Let it get too hot and pressure climbs, which pushes the mixture the other way, toward lean. Measuring pressure turns that guesswork into data. With a sensor connected, a Nexus ECU can:
- Log bottle pressure alongside everything else.
- Feed it into Engine Protection.
- Switch a nitrous stage off when pressure isn't where it should be.
- Turn a bottle heater blanket on and off based on pressure.
Up to four sensors can be connected, which helps on multi-bottle setups.
Setting it up in NSP
Calibration
The calibration node is where the ECU learns how voltage relates to pressure. If you're using a Haltech sensor such as the 2000 PSI brake/nitrous pressure sensor, use Load from File to bring in its calibration. For another brand, enter the manufacturer's figures by hand, then Save to File so you have it for next time.
Display
Two settings control when gauges, bars and number displays for this channel change to a warning state:
- Warning Minimum: the pressure below which the display warns.
- Warning Maximum: the pressure above which it warns.
Set them to bracket the bottle pressure window your nitrous kit maker recommends, so a glance at the dash tells you whether it's safe to spray.
Diagnostics
High and low voltage DTCs catch a damaged sensor or a wiring fault. Give each one a DTC severity and Engine Protection will act on it.
Wiring
Pressure sensors are analog, so connect the signal to any free AVI. Turn the pull up off for this input.
Fit the sensor where it sees true bottle pressure, close to the bottle, and keep the signal wire away from the solenoid and heater wiring.
To use the reading for stage control, look at nitrous activation and nitrous controller settings. New to spraying on a Haltech? Book a free consultation.
