LUV94RX7

Here's a nice post from th ebig list today:

"Water injection serves 2 closely related functions on a turbo engined car. Firstly it cools the charge air temperature by utilising the effect known as the latent heat of evaporation. This property can be self demonstrated very easily. If you pour something that evaporates quickly ike petrol on your hand it feels very cold. This is the rapidly vaporising spirit removing heat from your skin and bloodstream by the aforementioned process. By spraying a very finely atomised mist of water into the inlet of a turbo engine when under boost conditions the evaporation of the water causes a reduction in the air and fuel intake charge. A cold charge is less likely to be subject to detonation than a hot charge. A cool charge is also denser, able to carry more air and fuel mix per cubic foot. These 2 properties of water injection allow either less chance of detonation at a given boost, maybe allowing lower

octane fuel to be used, or to allow a rise in boost pressure usage

without detonation. These are very desirable goals for any modifier of a turbo engine, or one using an engine mapped to run on a higher octane fuel than generally available in the UK. Japanese import turbo cars for example.

People ask whether squirting water into an engine causes corrosion. In fact this is not a problem, the combustion temperatures under boost ensure the water is turned instantly to steam and is ejected out of the exhaust. The water mist is injected only when high boost is sensed via a supplied pressure sensor switch. The basic combustion process of hydrocarbon fuels causes water to be generated anyway, which is why cars not driven on regular long journeys will rust out a mild steel exhaust system form the INSIDE out. If water is added in the correct volume, via the supplied and calibrated jets, this is not a problem.

Even when used alongside a larger or more efficient intercooler, or indeed when an intercooler is used in an application where one was not present as standard, water injection can and does increase charge cooling still further. Water can be stored either in the existent windscreen washer bottle or in a separate dedicated container. In cold conditions it is essential to ad an anti freeze additive to the water to stop pump damage through freezing. Windscreen washer additive serves this purpose fine and the engine won't mind ingesting this solution at all. Or you can add neat Methanol, which is usually the anti freeze additive in washer fluid anyway. Using a 50 / 50 percent by volume water methanol mix will actually help increase the octane of the intake charge as an added benefit. As a yet further advantage the latent heat of evaporation of methanol is extremely high. A win/win situation. It is not however obligatory to use methanol as an additive. All components of the water injection kit that are in contact with the fluid are stainless steel or able to tolerate water and methanol or screen washer additive without degradation. A properly set up system does not use a vast amount of water, in fact a modern car sized screen washer bottle used also for the water injection reservoir will suffice admirably. A water filter is included to keep and sludge out of the pump or jet. This should be checked regularly for contamination and blown out if residue is

apparent within. -- Best regards, Chris Wilson mailto:chris@formula3.freeserve.co.uk

Ken

"94 White, Red Leather

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