What the intercooler function controls
The Intercooler System handles two separate jobs:
- Intercooler spray: a pump or solenoid that sprays water onto the intercooler core. Evaporating water pulls heat out fast, which is ideal for drag passes, hill climbs and short, hard runs. The ECU can fire it automatically when load, throttle and RPM are high, or you can fire it from a switch.
- Intercooler fan: a fan across the core, switched on and off by intake air temperature. Handy on front-mount cores that see little airflow at low speed, or on top-mount and rear-mount setups.
You can use either one, or both.
Choosing how the spray is armed
The Conditionally Triggered option decides whether the ECU is allowed to spray on its own.
| Mode | How spray is triggered | Good for |
|---|---|---|
| Disabled | Only the manual switch sprays | Drivers who want full control of their water supply |
| Enabled - Always Armed | Sprays automatically whenever the conditions are met | Track and drag cars that should always spray under load |
| Enabled - Arming Switch | Sprays automatically, but only while the arming switch is on | Street cars, so you only use water when you want to |
Separately, you can enable a Spray Manual Switch. Pressing it sprays regardless of the activation conditions, which is great for a pre-staging spray. A Spray Indicator output can light a lamp on the dash whenever the spray is running, and Fan Enable turns on the fan output.
Assigning inputs and outputs
Once the options are chosen, the Connections section asks you to pick hardware for each part you enabled:
- Spray Output: drives the spray pump relay or solenoid.
- Spray Auto Switch Input: the arming switch.
- Spray Manual Switch Input: the manual spray button or switch.
- Spray Indicator Output: the dash lamp.
- Fan Output: drives the intercooler fan relay.
Pumps and fans draw more current than an ECU output should carry, so switch them through a relay. A Haltech switch panel is a tidy way to add the arming and manual switches.
Switch types
Both the arming switch and the manual switch can be set as one of two types:
- Switch: an ordinary toggle that stays on or off where you leave it.
- Latching: a momentary push button. Each press flips the state from off to on, or on to off.
Match the setting to the hardware. A push button configured as a plain switch will only be on while you're holding it.
Spray activation conditions
In automatic mode the spray only runs when every condition is satisfied at the same time. Treat it as a checklist the ECU works through continuously.
| Condition | Spray allowed when | Our advice |
|---|---|---|
| Minimum Load | Load is above this value | Set it so spray only runs well into boost |
| Minimum Throttle Position | Throttle is above this value | High enough that part-throttle cruising never sprays |
| Minimum RPM | RPM is above this value | Stops spray while maneuvering at low speed |
| Minimum Coolant Temperature | Coolant is above this value | Keeps it off during warm-up |
| Minimum Air Temperature | Intake air is above this value | No point spraying a core that's already cool |
We set these with the water tank size in mind. A small tank empties quickly, so conditions that only trigger on genuinely hard pulls make each fill last.
Pulsed output
Both the spray output and the fan output have a Pulsed Output option. With it off, the output stays on solidly while active. With it on, the output cycles using a Pulse On Time and Pulse Off Time, both entered in milliseconds.
Pulsing the spray is a simple way to stretch your water supply: water keeps evaporating from the core between bursts, so short pulses can still do a lot of the cooling. Start with longer on times and trim from there while watching intake air temperature in your logs.
Intercooler fan settings
The fan uses two temperatures:
- Air Temperature On: the fan starts at this intake air temperature.
- Air Temperature Off: the fan stops at this temperature.
Set the off temperature a few degrees below the on temperature. That gap gives the fan hysteresis, so it doesn't click on and off every few seconds when air temperature sits near the switch point.
Troubleshooting
| Symptom | Usually |
|---|---|
| Spray never runs automatically | One condition isn't being met (often coolant or air temp), or the arming switch is off |
| Spray button only works while held | Switch type set to Switch instead of Latching |
| Tank empties too fast | Conditions too loose; raise load or throttle minimums, or use a pulsed output |
| Fan cycles rapidly | On and off temperatures too close together |
Intercooler system FAQ
Is intercooler spray worth it on a street car?
For repeated hard pulls or hot climates, yes. We usually pair it with an arming switch so it only runs when you choose.
Can I use it with the Nexus?
This guide covers the Elite in ESP. Ask us about the equivalent setup on your Nexus.
Related Elite functions: thermofan, boost control and air conditioner control.
