The Alfa Romeo 155 Q4 Waterspray system.
Series 1 cars.

<P1> <P2> <P3> <P4>

Waterspray functionality

The waterspray works to a very simple set of rules, if the engine is producing more than 0.7bar of positive pressure, then the system activates and sprays water over the intercooler. This is not the most effective nor efficient way of cooling the intercooler, but it does work. At the heart of the system is the pressure switch.

The switch (circled in the image above) is connected via a T-piece to the small bore pressure hose leading to the inlet manifold. The second T-piece and clear small bore hose in the image are the feed for an aftermarket boost pressure gauge. The pressure switch also has 2 electrical connections. One is a live feed and the other is connected to the input of the relay located in the car.
Once running and with the engine producing the requisite 0.7bar of boost, the switch closes and the live feed is presented to the relay. Simple really.

The relay to control both pumps is in the auxilliary fusebox which is located behind the trim panel below and to the left of the steering wheel. This is the panel that holds the headlight level adjustment knob.

In the fusebox there will be an empty slot for a fused relay, this is where relay part #60595829 needs to be fitted. With this in place and connected to the pressure switch and pumps, the waterspray should fire whenever the turbo is producing more than 0.7bar of boost. Hints on troubleshooting the water spray will come later in the article.

Assuming the relay is fitted correctly with its fuse, and the pressure switch is working correctly, once the engine makes the 0.7bar the switch activates, in turn activating the relay which sends a high power feed to the two pumps in the boot forcing water from the bag, through the hose and to the nozzle infront of the intercooler.

The water bag in the boot is located at the very rear of the boot on the left hand side, tucked behind the spare wheel. It is held against the side of the car via a couple of hooks at the top of the boot. In the image above the bag has been unhooked and is resting on the floor of the boot.

With the bag pulled forward you can see the tube that takes the water from the bag to the pumps. This is all that can be seen from inside the boot without removing trim. The rest of the workings are hidden behind the trim to the rear of the spare wheel bracket in order to keep things nice and neat.

<<Page 1 Page 3>>