MR2 Turbo Aquamist Installation: Overview

Water Pump	Water Line	Wiring	Parts List

Water injection is a time-proven technique for improving engine performance by reducing the likelihood of detonation in an engine. This is equivalent to using higher octane gasoline, except that water is much less expensive than fuel additives. In addition, water injection cools the intake charge which increases the density of the air entering the cylinders resulting in more power. While air charge cooling results in an immediate power increase, the greatest power potential from water injection is obtained by increasing boost, decreasing the amount of fuel in the air-fuel mix or advancing ignition timing to take advantage of the lowered detonation potential. These requires either a boost controller, a fuel computer, an ignition timing computer or a programmable EMS to fully exploit.

The installation described here is unique for an MR2 in that it uses the stock washer fluid reservoir. This reservoir holds over a gallon of water or water/methanol mix and is already installed in the vehicle. Having the water pump and water tank in the front is a better choice in terms of weight distribution on an MR2. It also eliminates the need to take up precious (in my opinion) trunk or engine bay space.

The Aquamist water injection pump is a high quality unit that provides over a 100psi of pressure to a water nozzle mounted on the intercooler-to-throttle body pipe. When water is forced through the injection nozzle at this pressure, it atomizes and provides a very good distribution of very small water droplets into the intake charge. These droplets require large amounts of heat energy to vaporize and it is this energy requirement that reduces detonation by cooling the intake, the combustion chamber and the exhaust gas leaving the cylinders.

This installation assumes that you have purchased an Aquamist 1s water injection kit (see the parts list section). Although the Aquamist instructions suggests that the washer fluid reservoir be used as the source of water or water/methanol mix, MR2 installations commonly add a tank either in the trunk or the engine bay since the washer fluid tank is in front of the passenger compartment and the engine bay is behind. Since the battery is also in front, a heavier gauge wire harness than the one supplied with the Aquamist kit is not required.

I strongly recommend that you use a water/methanol mix rather than pure water, especially if you ever drive in an area where the outside temperature might get below freezing. If you don't want to mess with mixing water and methanol, just use winter-ready washer fluid, which contains methanol and a little bit of extra soap that won't hurt the engine. If you mix your own water/methanol, never exceed a 50% methanol to water ratio, as this mixture will begin to lose the desired cooling properties of the water and start to behave like plain methanol fuel.