Updated: Oct 16, 2021
The job of an intercooler is to cool down the charged air coming from the turbo into the intake manifold. Spraying water onto an intercooler can increase it's heat transfer.
An intercooler water spray kit sprays a mist of water onto the intercooler, increasing heat transfer and reducing air intake temperature.
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Does It Work?
Intercooler water sprays do work. The video below shows the effectiveness of a water spray kit on intake air temperature.
One issue I could see with the this test is the water sprayer was homemade and only sprayed a small portion of the intercooler, as well as the water not being misted.
Providing a high-quality kit is used which sprays the water consistently, over the whole intercooler, and mists the water properly, the intercooler water spray kit is very effective at reducing intake air temperatures.
Intercooler sprayers are especially useful in regions with a hot climate and air temperature, in summer, or when using the car for hard driving such as track days/racing.
Intercooler water spray kits lower the air intake temperatures, increasing the density and oxygen quantity of the charge air - this has the following benefits.
A higher air density means there is more oxygen for the same volume of air.
Increased oxygen in the charge air means that more fuel can be added to the air/fuel mixture, improving power output from the engine.
Faster Turbo Spool
This increased air density, oxygen density and power output means that the turbo may potentially spool faster, reducing the time required for turbo boost to reach its target.
For example; instead of reaching full boost at 3000rpm you may reach full boost at 2800rpm, improving throttle response and allowing for faster acceleration.
Because an intercooler water spray kit doesn't require any energy from the engine and it doesn't add too much weight, it can improve efficiency.
Driving in cold weather, such as in the winter, has the same effect on efficiency due to the reduced ambient air temperature.
Therefore, reducing intake air temperature can improve a vehicles fuel efficiency.
There are only a couple drawbacks associated with an intercooler water sprayer kit.
Slightly Increased Weight
An intercooler water sprayer kit adds some extra weight onto the car, such as the water storage tank, the piping, and sprayer nozzles.
Although the weight isn't much, it is still extra weight that can add up.
Due to the various piping, water storage tank, and the placement of the water sprayer nozzles, it can become complicated to install.
You also need to think about where the activating mechanism goes, some spraying kits are also activated via the ECU or automatically in one way or another.
It can become complicated if you are inexperienced.
DIY Intercooler Water Sprayer
Surprisingly, tapping into the windshield washer hose is one of the easiest methods to set up a low-cost intercooler sprayer.
Once you've tapped into those windshield washer lines, run an extra line to the front of the vehicle, where the intercooler is located.
From here, installing 2-3 fine mist sprayers, such as those found in the lawn and garden department of DIY and garden stores work perfectly.
Make careful to point the sprayers towards the intercooler so that you can saturate the whole surface area of the intercooler, try to evenly space the sprayers out.
Once this is installed, you can simply spray the windshield wipers and it'll still allow windshield cleaning but also spray the intercooler sprayers.
What Liquid Should I Use?
Usually only water is used in an intercooler sprayer kit, but sometimes tuners add in ice to reach sub-ambient air intake temperatures.
A highly evaporative substance such as ethanol, as found in glass cleaner also works well to pull heat out of the intercooler.
A 50/50 mixture of glass cleaner and water or ice water can be an amazing way to cool down air intake temperatures.