What water injection does
Spraying water, or a water and methanol mix, into the intake cools the charge as it evaporates. A cooler, denser charge is less prone to knock, which can allow more timing or boost on a given fuel. It's popular on boosted street cars running pump gas. The catch is that it has to be reliable: if the tune depends on the spray and the spray stops, the engine loses its safety margin.
How the Nexus setup is organized
The advanced water injection function in NSP is split into separate pages, and each has its own article:
- Wiring: connecting the pump and any related inputs to the ECU.
- Fuel correction: adjusting fueling while injection is active.
- Ignition correction: adjusting timing while injection is active.
We work through them in that order: wiring first, then confirm the system is spraying when commanded, then add fuel and timing changes in small steps while watching logs.
Only add timing for water injection once you can confirm it's flowing, and make sure you have a plan if the tank runs dry. The simpler version of this function is described in water injection. If you'd like help planning a setup, book a free consultation.
