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Intercooler Water Spray

Keeping the intake air cool is very important, particularly under racing conditions, hence why we have an intercooler at all. For the rare times I go to the drag strip to record my quarter mile time, I thought the installation of a water spray kit to cool the intercooler may be worthwhile.

Initially I am just going to install a very simple system with no electrical controls beyond the existing windscreen washer. So when at the track, I'll need to turn two 4mm hose valves to divert the washer water to the intercooler and unplug the wiper motor. This allows me to spray the intercooler by operating the windscreen washer switch and prevents the wipers from operating.

Total cost for this modification as above is less than $10 plus about 1.5 metres of 4mm vacuum hose.

Its also not difficult to connect a frequency switch into the washer circuit to operate the spray at a given rpm. I may add this to the system in the future. This will still leave the system somewhat "manual" - the switch and valves will still need to be operated in the engine bay prior to using the spray, but it will automate when the spray is activated. Given the infrequent number of times I require an intercooler spray, I don't think it necessary to start adding extra water storage, pump, etc to make the system a full time, permanent accessory.




 

Materials and tools required:
2 x brass irrigation sprinklers
2 x 4mm irrigation tee pieces
2 x 4mm irrigation stop valves
1.5m) 4mm silicone vacuum hose or similar
A few cable ties
Side cutters


   
 

Cut a couple of short pieces of the vacuum hose and connect to a tee and the valves.

 

 

   
  Place in car and cut a piece of vacuum line long enough to go from the washer motor to the tee.
* Note the drain trap in the vacuum line. This is needed to prevent the water draining from the tank through the intercooler spray nozzles.
Disconnect the washer water hose and connect to one of the valves.
Cable tie in place.
Install the hose from the tee piece to the washer nozzle.



   
   

 

   
  Now just for the sprinklers themselves.
The picture on the right is the hosework required for the top of the intercooler plus the sprinklers. You'll just need to adjust the length of the hoses to suit your intercooler.

 

   
  Install the sprinklers to the hose, install roughly in position above the intercooler and run a hose from the tee piece back to the valve.

 

   
  Cable tie in position and adjust nozzles as required.

 

   
 

So for day to day driving, open the valve that goes to the windscreen washers and close the valve that goes to the intercooler sprinklers.

For intercooler spray:
- close the valve that goes to the windscreen washers
- open the valve that goes to the intercooler sprinklers
- unplug the windscreen wiper motor (see pictures)
- to operate, simply activate the washer switch from the drivers controls.

   
       
         
  If you want to automate the above to operate at a certain rpm, you'll need to:
- grab a Frequency Switch kit and assemble it
- install it under the dash somewhere
- wire up the power and ground input, tacho input and run a switched wire to activate the pump
- install a switch adjacent to the washer motor (to select normal windscreen washer control or frequency switch control)
- reconfigure a bit of wiring to the washer pump.
     
 

The kit

 

   
 

The assembled kit

 

   
 

The assembled kit installed in the enclosure.

The wiring consists of:
- 12 volt supply (bridged to the common of the output relay)
- Negative
- switched 12 volt supply from the N/O contact on the output relay to the pump
- tacho input

Adjust the frequency switch to the required rev level, and the gain pot for relay drop out level.

 

   
 

The tacho signal can be picked up from the ECU or EC-AT. From memory, the tacho wire is white with silver flecks. If anybody needs confirmation I can check where I tapped off the tacho cable for my shift light.

   
  Here's a wiring diagram of what needs to be installed at the washer pump.    
 

This system requires operating by:

For day to day driving
- open the valve that goes to the windscreen washers and close the valve that goes to the intercooler sprinklers.
- place the switch in the position that will allow the drivers control of the window washers to operate.

For intercooler spray:
- close the valve that goes to the windscreen washers
- open the valve that goes to the intercooler sprinklers
-place the switch in the position that will allow frequency switch control.

While this is not a fully automatic system, it relieves the driver of the responsibility of manually operating the sprayers. It also ensures the sprayers operate at the predetermined level that you want.
To preserve the integrity and safety of having full time window washers, a fully automatic intercooler spray (installed permanently) would require, at bare minimum, the installation of a dedicated pump. A larger volume water reserviour would also be important for prolonged usage, and also to maintain water for window washing requirements.