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Water Injection


Guest EncoreWRC
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Guest EncoreWRC

Can anyone tell me about water injection. I know what it does but after some views, and where to get it and how much I should be paying?

 

I have emailed Chris Wilson but no reply for weeks so I need advice from anyone that knows....

 

Cheers

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I have an Aquamist 1s which I purchased months ago and CW fitted it last week, I cant remember where I got it though.

 

At the moment I have to just keep an eye on it and top it up but I am currently looking into the Aquamist DDS3 gauge display which shows flow rate and fluid level.

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Must have missed the mails, sorry, I seem to get so many. Here is an article i wrote on WI a few years ago. I sell and fit the ERL Aquamist kits and rate them highly:

 

 

Water injection serves 2 closely related functions on a turbo engined

car. Firstly it cools the charge air temperature by utilising an effect

known as the latent heat of evaporation. This property can be self

demonstrated very easily. If you pour something that evaporates quickly

like 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 into steam causes a temperature 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 unit of volume. 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 LOTS of water to be generated anyway, which is why cars

not driven on regular long journeys will rust out a mild steel exhaust

system from the INSIDE out. If water is added in the correct volume, via

the supplied, 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 existing windscreen

washer bottle or in a separate, dedicated, container. In cold conditions

it is essential to add 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 any sludge out of the pump or jet. This should be

checked regularly for contamination and blown out if residue is

apparent within.

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Water injection serves 2 closely related functions on a turbo engined

car. Firstly it cools the charge air temperature by utilising an effect

known as the latent heat of evaporation. This property can be self

demonstrated very easily. If you pour something that evaporates quickly

like 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 into steam causes a temperature reduction in the air and

fuel intake charge.

 

Chris / Other people that know,

I'm curious about the idea of utilising the Latent heat thing. I was just thinking though, does that really happen in an engine? The reason why it feels cold when you put some liquid that evaporates quickly on your skin, is that it's removing heat from your body and dissipating into the air. So heat is leaving your body and is being transferred to the world around you, making you feel cold. In an engine, the water, even if turned to steam, (which I'm not 100% sure it would due to the combustion pressure, which would increase the boiling point greatly, but that's just a guess, and I've not really thought about it, and can't find my old steam tables) still contains the heat that has been transferred to it from the air as it's got nowhere to go. The only difference being that for a volume of "charge" you now contain an amount of water. OK the air may be cooler, but the water is warmer. See what I'm saying?

I don't know if that's what happens, simply asking if that makes sense?

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