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Water Spray DIY | intercooled Subaru engines | Denver Performance Shop

[fa icon="calendar"] Sep 6, 2015 9:30:00 AM / by Mike Wiener

intercooler water sprayEveryone is always looking for a quick project they can do themselves, at home, without blowing up their car. The Intercooler sprayer is one of those mods.

First, let me explain a bit about what this does to your intake charge. When a liquid evaporates or boils into a gas, a tremendous amount of energy is required to complete that phase change.

This energy is provided in the form of heat. By spraying a liquid onto the Intercooler, heat is absorbed by the liquid, and carried away by the resulting vapor as it evaporates. Three to six times more heat can be removed in this process than by air alone blowing over the core. And as all of us turbo guys know, that turns into more power, more dense cooler air feeding the engine under boost.

Before you check this mod off as a hack, remember that there are a few cars that come from the factory with water spray systems, like the Subaru WRX STi (Hill climb and rally cars frequently have them too).  As a Denver performance shop, we do build them as well, for this article it is all about DIY projects for your turbocharged Subaru.

A trip to the local parts store and Home Depot should get you all the parts you need. The parts store will have a windshield washer pump and tubing. Home Depot has small sprinkler heads that will mist water and various T connectors (think water delivery systems for plants / gardens).

Water Spray DIY | You'll also need some kind of container to hold your liquid.  Smaller wiper fluid bottles can be found at the parts store, larger tanks from the Depot.  There are many different ways to build this, and we have done several, the goal is to get it to work for your budget.  

After mounting your tank and plumbing your pump, lines, and sprayers, all you need to do is wire it up. You can find simple timer circuits online that will allow you set how long the system will spray each time you press the button. You could also install a throttle switch to spray whenever you floor it. A simple button works too.


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The hotter it is outside and the hotter the engine, the better the sprayer works on your intercooled turbo. You can also add alcohol (Wiper fluid), which evaporates faster, to get lower temps on the Intercooler.

Mike Wiener

Written by Mike Wiener