Water injection is a technique used to cool the combustion chambers of engines by adding water to the cylinder

VW car tuning tips: Water injection

Water injection is a technique used to cool the combustion chambers of engines by adding water to the cylinder. This results in a higher compression ratio, and helps to decrease the problem of engine knocking greatly. Hence it increases the octane rating of the fuel, as it does not burn, therefore some performance can be attained when used in a combination with turbochargers and other alterations.

The piston in the engine is pushed downwards as water changes to steam by the heat of the fuel ignited. The water converting into steam, allows the temperature to decrease, as heat is then absorbed out of the combustion chamber. This process also cleans out the combustion chamber, as it cleans the carbon build up.

We feel that water injection is a very effective method, because it gives you more power than using the same amount of extra fuel. However we would advice you to be careful when injecting the water, because if you add to much water, you are at a risk of losing your power, because extra water would mean that the combustion chamber is overcooled.

The right method to connect the water injector to your Volkswagen engine is by having a pressure-sensitive switch that controls a water pump and to find out how much water is required for the water injector, an rpm sensor can be used. Therefore when the switch senses that the manifold vacuum has gone up to a certain extent, it would then turn the pump on.

There is a need to maintain water injectors from time to time, because if they are not sustained properly then you risk the problem of water harming the aluminium of the head, and at times the water may reach the crankcase, which would then damage the valves and the exhaust system. Due to these setbacks it is debatable whether water injectors are more harmful than beneficial. However it is clear that if you want to add some extra power to your high performance Volkswagen, then water injection could prove to be useful.