Just ran across some info on a car (not air cooled) running water injection. Got me thinking, never hear of the high HP air cooled cars running it? Do they run it and I just missed it? Or is it a secret not to be talked about?
Just curious since it sounds like it raises compression - good for racing and street performance.
And also lowers emissions - can help in the long run on the street.
Here is some basic info I found on it:
Water injection (engines)
Water injection, also known as anti-detonant injection, is a method for cooling the combustion chambers of engines by adding water to the incoming fuel-air mixture, allowing for greater compression ratios and largely eliminating the problem of engine knocking (detonation). This effectively increases the octane rating of the fuel, meaning that performance gains can be obtained when used in conjunction with a supercharger or turbocharger, altered spark ignition timing, and other modifications.
Composition of fluid
Many water injection systems use a mixture of water and alcohol (approximately 50/50), with trace amounts of water-soluble oil. The water provides the primary cooling effect due to its great density and high heat absorption properties. The alcohol is combustible, and also serves as an antifreeze for the water. The purpose of the oil is to prevent corrosion of water injection and fuel system components.  Because the alcohol mixed into the injection solution is often methanol (CH3OH), the system is known as methanol-water injection, or MW50. In the United States, the system is commonly referred to as anti-detonant injection, or ADI.
In a piston engine, the initial injection of water cools the fuel-air mixture somewhat, which increases its density and hence the amount of mixture that enters the cylinder. But the greater effect comes later during combustion when the water takes in significant amounts of heat energy as it converts from liquid to gas (steam). This increases piston pressure (torque), reduces peak temperature and resultant NOx formation, and reduces the amount of heat energy absorbed into the cylinder walls. The alcohol in the mixture burns, but at a much slower rate than gasoline. The net result is that the combustion process happens slower, preventing the destructive supersonic shockwave characteristic of detonation.
When used in a turbine engine, the effects are similar, except that preventing detonation is not the primary goal. Water is normally injected either at the compressor inlet or in the diffuser just before the combustion chambers. Adding water increases the mass being accelerated out of the engine, increasing thrust, but it also serves to cool the turbines. Since temperature is normally the limiting factor in turbine engine performance at low altitudes, the cooling effect allows the engines to be run at a higher RPM with more fuel injected and more thrust created without overheating.  The drawback of the system is that injecting water quenches the flame in the combustion chambers somewhat, as there is no way to cool the engine parts without cooling the flame accidentally. This leads to unburned fuel out the exhaust and a characteristic trail of black smoke.
Fuel economy can be improved with water injection, although the effect on most engines with no other modification, like leaning out the mixture, appears to be rather limited or even negligible in some cases.
Some degree of control over the water injection is important. It needs to be injected only when the engine is heavily loaded and the throttle is wide open. Otherwise injecting water may simply drown the engine and cause it to quit.
Use in automobiles
A limited number of road vehicles with large-displacement engines from manufacturers such as Chrysler have included water injection. Saab offered water injection for the Saab 99 Turbo. Subaru has also offered a factory water injection system on their high performance model the Impreza WRX STI. With the introduction of the intercooler the interest in water injection disappeared, but today, water injection is also of interest because it can potentially decrease nitrogen oxide (NOx) emissions in exhaust. The most common use of water injection today is vehicles with aftermarket forced induction systems such as turbochargers or superchargers, particularly those used for drag racing and illegal street racing.
Here is a website about water injection, the history and race use
And here is a High Performance Water/Methanol kit for HIGH HP output
Just curious because it all sounds good. Especially for the turbo guys!!