Aquamist Gives the Subaru a Safety Injection

Most people have heard of Aquamist, but few know what it actually does. The South African agents, Guru Performance Parts, were kind enough to deliver the unit that will be fitted in the Subaru STi to my office today.


The main function of Aquamist is to suppress detonation caused by high temperature and pressure developed within the combustion chamber when the effective compression ratio has been taken beyond the auto-ignition point by either a turbo or a supercharger - phew!


Basically, water (when pumped through the above Aquamist Injection System) has a high latent heat content - this is extremely effective for controlling not only the onset of detonation but also the production of oxides of nitrogen in modern day engines.

Water injection will not increase the power normally. But in countries like South Africa where the ambient temperature is very high, injecting water will lower the inlet charge temperature producing a small power increase.


In addition to the actual pump, the Aquamist Injection System has several other important components. A float switch is linked to an LED light through a relay to tell you when water is running low. Another light linked to the same relay indicates that the system is active. A pressure switch is mounted in the vehicles manifold and set to activate at a specific boost pressure. When the manifold boost pressure reaches the preset level, the relay activates the pump which sprays water into the intake of the motor. Tada!