I use an Aquamist water injection kit on my Mk2 16v Turbo. It injects through a 0.05mm jet into the top of the intercooler, it is atomised before it enters the throttle body.
The water cools the charged air, the cooler the air, the denser it becomes. The cooler the engine the less chance of detonation
When my car was setup on Stealth's rollers, after about 10 runs the inlet manifold was ice cold to the touch, Vince told me he had never done so many runs in a car without letting it cool in between. Stealth sometime after this became an agent for Aquamist.
Taken straight from Stealth's website:
Stealth Racing have now become an agent for ERL's Aquamist water injection product. Designed predominantly to provide in cylinder cooling for forced induction cars, these systems sit at the very front of the water injection market.
As any turbod or supercharged car owner will testify, a major threat to a force fed motor is the potential onset of detonation. This is the practice of spark plug igniting the fuel / air mixture before the piston has reached the top of it's sweep. The result (if left alone) is a damaged piston or two, leaving no other choice but to expensively rebuild the engine.
Methods of reducing the onset of detonation, include retarding the ignition timing or relying (where possible) on electronic control devices such as the knock sensor. Both of these will do the job, but retarding the timing will compromise the power output of the motor and relying on the flimsy safety net of a knock sensor is never a wise move!
A more effective method of preventing detonation, is to lower the in cylinder temperatures. Fuel is a good temperature cooler, but constantly dumping petrol into the engine is liable to wash the cylinder bores. Traditionally, intercooling or chargecooling are used to lower the temperature of boosted air before it reaches the engine. This is a very good start, but technical limitations mean that the efficiency of these cooling methods is plateaued and still will not prevent "pinking" in some applications. Enter water injection, a proven cooler in F1 and rally applications, now making a name for itself in fast road applications.
