This is something I've been wanting to do for some time. The Impreza WRX STi comes with this standard. The purpose is to spray a mist of water on the IC and help the intercooler pull more heat out of the air going into the motor. As everyone know's cool air is better for the motor.

I've kind of done this in stages and hope I can do a good enough write up that will be understandable. I am working with Mo_Boost (Perrin R aka P-Rod) on his automatic IC spray setup and Clock Gauge Modification. I'm going to be a beta tester. Part of his system is an add on IC spray kit. So some of my parts he supplied and will come with his kit. Some parts I got myself. I test Mo_Boost's setup I will do a page on that.

This mod will mostly be pictures of parts and stuff like that.

Here are some of the things I purchased:

OEM STi IC Water Spray switch - PN 83001FE020
note on the switch, it's too big and needs to be modified to fit properly, if you aren't comfortable doing that you can get a normal momentary switch instead.

OEM Check Valve - 86634AG010 - for the fluid supply line, this will prevent back flow, and the need for the pump to push the water all the way up the hose.

4 Vacuum Tee's - 5/32nds all round - The Part number for the Vacu-Tite! brand is 47333 for a box of two. These are for the sprayer manifold and to tap into the existing washer line.

1-90° 5/32nds elbow - This is optional, I used this on the end of the spray manifold to make it look nice, you can just put the end hose in the spray connection w/o the nice turn.

Anco Washer Pump - PN 65-01 To power the sprayer

About 5-6' of 5/32" vacuum hose for the spray kit

Ok, here is a description of what I ended up doing and why.

The pump:

The OEM pumps (front and rear) are the free flow type. Meaning fluid will flow through them even when they are off. This is a good thing because you can just cut into the existing hose and T off to supply another pump. This is a lot easier than poking a hole in the tank. The trick is to get a spray pump that dosen't let fluid through when it's off. The pump I found is like that. It took me a while to find one. The guy at the store thought I was crazy opening boxes and blowing into washer pumps but he was nice enough to humor me :).

I installed the pump under the fuel filter using an existing threaded hole that was there. I was only able to secure one side but it seems to be pretty solid so far after a few weeks of driving. I put the black lead to an existing ground and used a relay for the other side directly to the battery. The coil side of the relay taps into one of the existing wires on the OEM washer pump, they are hot (+) switched, The other side of the relay I ran through the fire wall grommet. Look here for details on that:

http://www.scoobymods.com/forums/showthread.php?t=3460

This wire I went to the switch and the other side of the switch to ground.

Here are some pics of the pump and it's location.


Peaty 6/5/2004

The spray mainifold:

The brass fittings and mist nozzles were supplied by Mo_ Boost. The Pics will show how I set up the manifold

Check valve and spray pattern

Button / Switch to activate the pump:

The first switch I installed was a small momentary switch that I hid by the dead pedal. I had an OEM switch on order but I wanted to test the system before I got it. I could activate the spray by just pushing my foot sideways. It worked OK but it as not as fancy.

I liked the idea of the OEM switch better, it's in an easier to get to spot and looks pretty spiffy.

I got my Switch from Jamie (aka Subie Gal) at Carter Subaru: 800 426-1332

The bad news is the switch's button is too big compared to the OEM Forester buttons :( The good news is I don't give up that easily :p Here you can see how the button compares. Also notice the Forester buttons are contoured a little different too. Unless you really scrutinize them it's not all that obvious though.

As an aside, the bottom knock outs will hold the larger switch but it looks funny as you can see. I suspect the knock outs are for something like a headlamp washer spray and headlamp leveler buttons as those mount horizontal.

So what I ended up doing was taking the switch apart, marking the button as to how much material I had to remove and take it to my grinding wheel. I put some masking tape on the button at the score line to protect it from getting scratched as I was messing with it. I ground almost all the way to the line then the last little bit I use a fine file to round the edges to make it look as nice as possible. Here you can see the switch apart and some general switch pics.

Something interesting to note, it looks like there are two bulbs in the switch but there is only one. The one that comes on with the dash lights to light the letters. There is no light to show the switch is activated.

Wiring up the switch

OK for the fun part :rolleyes:

Since there is no plug to put in the back of the switch I had to make my own of sorts. Using the wiring diagram from the STi's Spray switch and the Fog lamp one form the Forester XT I was able to figure out how to set it up. First I used some nippers to remove the plastic around the pins in the back so I could get to them easier to solder on the leads. I figured out which pins were which and used my soldering iron and some shrink tube to put leads on. I put spade connectors on the leads that were coming from the pump (one from the pump and one went to ground) so I could disconnect the wires in the event I needed to remove the panel the switches are mounted on. The other leads I just cut because those are for the dash lighting and I used vampire taps into the fog lamps harness leads. I'm attaching the pics here that will give you an idea how I did this whole deal.

Here is how to drop the panel to get to the switch blanks. There are two screws on the bottom of the panel. Then just gently tug it off. I had the whole carrier removed but that's not needed. I had to do it to figure out how the heck I was going to get the switch to fit. Also there is a pic of how I use the vampire taps for the dash lighting.

A couple of things to note. During the summer I fill the washer bottle with regular water. I happen to use carbon filtered water because I have a big carbon filter under my sink. Both my front and rear washers work fine and this mod does not interfere with their operation.

I just noticed I forgot to show how to remove the metal snoot that comes down from the scoop to the IC :doh: Well here you go:

There are 6 - 8mm screws (you can use a screwdriver too) to remove and one major PITA plastic fastener. The fastener is a bugger because it looks like you can get a Phillips screwdriver in there and screw it out. That dosen't work though. What I found out was I had to get a thin blade of a pocket knife or something similar under there and start to pry it up enough to grab the head with my fingers and yank it out then remove the back part. Get that out first, do the rear three and get the front three last. The rear has tabs that go into the hood so the back will be held in place while you remove the front screws.

OK the wiring of the relay.

I'm not an electronics wiz. Please have a look at this thread regarding relays:

http://www.scoobymods.com/forums/showthread.php?t=3190


I used a relay to operate the pump. You can see in these pics where I picked up the Power for the pump though the relay. Directly to the battery. Also, the switched power to energize the relay when the button is pushed I got from putting a bare wire under the harness plug to the OEM pump. Since this is temporary I just stuck it under the spade of the harness. If it were to be permanent, I would most likely have used a vampire tap instead. I used one of the pics from the above link and put my text on it to show where the wires go on the relay. For the grounding of the IC pump you can see that in the above pics. For the ground wire of the switch in the cabin I used an existing nut under the dash. I hope these pics make the wiring of the relay understandable. If not please e-mail me and I'll try to clarify.