Do-It-Yourself

Water/Alcohol Injection System and Intercooler Sprayer

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In the interest of benefiting our fellow turbo enthusiasts, we have decided to provide a "how-to" and parts list to construct your own budget, water injection system.

We're sorry, but despite multiple references to the "kit", we no longer offer one for sale.

Click here to go directly to the "how-to" page

Applications: All Intercooled and non-intercooled turbo engines. Although these pages were written for a system that injects before the turbo, the higher pressure pump listed in the "how-to" section should allow injecting AFTER the turbo.

Purpose: To allow more boost by suppressing detonation--also known as the poor man's intercooler. This system may also be used as a cooling device for your intercooler. A small bracket, to position the nozzle, is all that you need to provide.

What makes our system different: Our kit is designed for the budget enthusiast. We have developed unique solutions to some of the more expensive pieces sold in other kits. We feel that we have struck a good balance between price and functionability. Additionally, we provide a special nozzle that vaporizes the water charge before it is ingested by the engine. This results in better cooling of the air entering the turbo and significantly reduces any abrasion that may occur when the water meets to turbo blades. The added cooling provided by vaporization of the charge increases power. This method is far superior to the squirt nozzles that are sometimes mistakenly used in home grown systems. When used as an intercooler sprayer, the vaporizing nozzle provides good distribution at the airflows encountered "at speed"

What's in it for me?: Recently, while building a water injection system for friend, it occurred to me that others may have a need for such a system, but lack the time required to gather the proper components. Additionally, even the most basic systems on the market cost twice as much(Spearco), and the really good systems (ERL) approach $1000. No one seems to provide a basic system at a fair price. So, you can reproduce ours using the "how to" section.

Note: Please read the FAQ and how-to page carefully. Dawes Devices cannot be held responsible for damage occurring from misuse or non-compliance with the anti-siphoning guidelines.

Water Injection Facts:

When increasing the boost level of a turbocharged vehicle, an undesirable byproduct is an increase in intake temperatures as well as a corresponding increase in combustion temperatures.. These higher intake temperature increase the chance of detonation within the cylinder. The best solution is to add an intercooler when the boost pressure exceeds 12 psi, but this is not always practical due to cost and packaging limitations. The early Chrysler TI (drawthrough) turbo engines are a good example of packaging limitations. It is somewhat difficult to fit an aftermarket intercooler to the factory manifold. This makes it a good candidate for water injection.

Water injection decreases the possibility of detonation by lowering the combustion chamber temperatures and increasing the effective "octane" of the fuel. This allows the engine to run a higher boost and full spark advance without the use of race gas. Additionally, if the water is atomized in the intake stream, there is an additional cooling of the intake charge. Both effects are increased with the inclusion of 50% alcohol to the mix (don't spray the exterior of an intercooler with alcohol!, this refers to internal injection only). The additional fuel of the high octane alcohol will in turn allow boost beyond what the factory fuel system can deliver.

Water injection also has the effect of "steam cleaning" the combustion chambers and exhaust valves. This removes the carbon build up that decreases efficiency and leads to pre-ignition (detonation). It will also keep the throttle body and interior of the intake manifold much cleaner than normal.

Water Injection FAQ:

Will water injection increase my horsepower?: Yes, but not directly. Water injection works to eliminate detonation, also known as knock. The big gains come from the ability to increase boost as well as the full ignition advance allowed by the ECU when it does not detect knock. While the cooling of the intake charge will produce some power increases, those increases are cancelled by the charge space occupied by the water vapor. In other words, there is slightly less room for air and fuel. However, by using up to 40 percent alcohol with the water, additional cooling takes place before the turbo, and the alcohol works as a fuel in the charge. This results in an increase in power.

Is water injection new?: No. Water injection was used during WWII to surprises detonation in fighter aircraft and increase their service ceiling.

Does the water "burn" in the engine?: No. The water simply converts from a vapor to a gaseous state which absorbs huge amounts of heat, due to the energy required to transform it.

What if my engine has an intercooler?: We do not suggest injecting water before the turbo in an intercooled application, as most of the water will condense out at the intercooler. However, our system works great as an auxiliary sprayer to increase the efficiency of your intercooler. In this application, water (add ice if you wish) is sprayed on the exterior of the intercooler to carry away the heat. Simple, easy, and effective. Subaru WRX rally cars use the same type of sprayer on their intercooler (but I bet it cost more).

Do I need an extra "tank"?: No. Our systems are designed to use the original washer fluid tank (most have a built in level sensor), but you may choose to add a separate tank which you supply. The alcohol/water mix actually works like washer fluid, so you can kill two birds with one stone.

How often do I need to fill the tank?: It all depends on how often you use the system (it's only active under high boost) and how big the tank is. Even the smallest tanks will last for 8 full 1/4 mile runs or so. In around town driving (racing?) a tank full should out last a tank of gas.

What do I need to install the system?:

In addition to the parts in the "how-to" section, you will need the following:

2) An 1/8 in pipe thread tap for the water fitting to your washer tank as well as the appropriate drill bit ($6 for both at the hardware store)

3) Optional---you may wish to use a solenoid valve to cut off water flow when the system is idle. We provide a siphon block to provide this function, but it must be mounted above the washer tank. In some applications it is more practical to use a solenoid valve. You can get one for a couple bucks at the boneyard. The boost control solenoid, from the passenger side fender of most Dodge turbo cars works great. We do not supply solenoid valves due to the high cost of a "new" unit.

4) Optional---I prefer to use the washer tank as my water supply, but you may want to use a separate tank.

5) A switch to turn the system on (ask us for our $20 pressure switch)

This page was updated on:

10/07/08