Tuesday, August 17, 2010

DIY Turbo Intercooler Water Spray System

The idea behind the project is to reduce some of the heat soak on the SAAB 9-5. I think every 9-5 owner in a warm climate has exited the highway in the heat of summer and found the car lacked power once they tried to enter street traffic. It's especially scary when making a left turn and finding the car will barely move. This is a simple and cheap project that only takes an evening to install and can hopefully reduce or eliminate the heat soak symptoms for many of the 9-5 owners out there.

To be clear, the better solution is to replace the stock intercooler (located behind the radiator) with either a drop-in performance model or a custom FMIC (front mount intercooler). I understand that both options are expensive and could be mechanically difficult  for some people, so I looked into this easy and low-cost water spray system.

The cost of this intercooler water spray system is about $50.

You will need:
Trico Products 11-102 Windshield Washer Pump
ScanTech Windshield Washer Check Valve
Toro Blue Stripe Drip Fogger, 3.0 GPH Model # 53651
Toro Blue Stripe Drip Starter Kit Model # 53724
Cable Ties

You'll have a lot of options on this project. Feel free to experiment with other parts and see if you can improve on this basic design. Leave a comment on this post if you discover something that might help others.


You can purchase all of the Toro "Blue Stripe" parts separate, but I found it costs less to just get the "starter kit" and the fogger heads. If you don't get the starter kit you will need some blue stripe tubing (maybe 10 feet worth), four "Blue Stripe" fogger heads, and five of the "Blue Stripe" T-connectors. The heads that come with the starter kit will not work in this project because they are designed to drip and not spray.


The washer kit listed gets you all the parts you need on that end of the system. You could pick up used parts and save some money. You'll need the water reservoir, a pump (able to create 10-30psi), a switch, related wiring, and some extra tubing if you decide to buy the parts separate.


These instructions are for a four spray-head system. It could be adapted to a two head system that only shoots water on the lower part of the radiator and intercooler. This could be a good option if you have trouble getting to the area behind the front grill of the car. I don't have first hand experience with the 2003 and newer 9-5s, but they look like a pain when it comes to grill removal. On the '99-02, you can just pop the entire grill off with a little pressure.

Instead of the momentary switch that comes with the washer kit, you could use a mercury switch attached to the accelerator pedal or a Hobbs-type pressure switch that will automatically activate the spray at a specific turbo pressure. One issue I can see with more automated switching systems is the amount of water in the reservoir. I get about 1 minute worth of spray per 2-quart tank. You'd quickly run out of water if you weren't careful.

The Instructions:

Lift and prop the hood

Detach the battery during installation. We're working with electricity and water here.

Remove the front grill or whatever it takes to get get access to the area in front of the radiator.

Roughly measure the length of tubing needed to go across the front of the radiator, down both sides to the lower part of the system and across again. For me, I cut two 1'6" lengths of tube and two 1' lengths of tube. This left me with plenty to trim for an exact fit later.

Cut four tiny 1.5" lengths of tubes. These will connect the fogger heads to the T-connectors.

Gather the four fogger heads, five T-connectors, the check valve, and some zip-ties

The check valve works as show below. Be careful that you have the flow going the correct way or the water won't move when you press the button.



What you're going for is something similar to the above. The tubing is in tan, the foggers are "O", the T-connectors are "T" and the check valve is the "L" shape.

Start at one fogger, attach the tubing and zip-tie it to the car, then work around to the next fogger. I tried to do all the plumbing and then install, but I had to trim just about every piece of tube once I got it behind the grill. So I recommend building it in place and only trimming the tubes once.


I placed the top two sprayers beside the horns, using the horn brackets to hold the sprayers in place.


The bottom two sprayers I attached to the lower grill area.

Once all four foggers are in place and connected to each other, you can roughly aim the heads where you want the water mist to hit. You then fine tune the aim once everything is up and running.

Follow the instructions that come with the washer kit on how to plumb the reservoir to the motor and connect the wiring.

Now is a good time to install the switch. The location and whatnot are up to you, obviously.

There is a nice space for the water tank between the battery and the headlamp. Use your favorite method to secure the tank into place.


Run a length of tube from the check valve to the washer motor and then fill up the reservoir with water. The system should be complete. I found that I had to run the washer pump motor longer than I expected the first time to get water flowing into the system, but the check valve will keep the water in the tubes once it's there so you won't have to prime again.

You should see something like this:

The videos doesn't do justice to the amount of water being sprayed. It's a very fine mist, so you're only seeing the largest drops in the video. I plan on putting butcher paper on the radiator and recording the spray again so you can see where all the water is going. It sprays at about 2-quarts per minute.

Fine tune the direction the water sprays and check for leaks. I had to zip-tie the tubing where it attaches to the pump because it shot off from the pressure the second day I tried it.

I haven't used the probe thermometer to check for exact changes in temperature, but I can get the radiator water temperature gauge down to what should be about 195 degrees* with the spray system (9 o'clock on the gauge), this at highway speeds on a 100+ degree day. It'll take a real thermometer to find out what is truly going on, but the basics are there.

*I had the dealer change the sensitivity on my stock water temp gauge with the use of a Tech II a few years ago so there should be little to no dead spot in the gauge reading. Still not ideal for real data, but gives a rough estimate about changes in temperature.

Special thanks to a certain SAABCentral member that helped me with this project, but wishes to remain anonymous.

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