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Water Injection, declined in popularity, why??


Chris Wilson
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Dunno Chris,

A lot of people may think they are not pushing boost enough to warrant WI or WI/Meth injection. I agree it is something that is overlooked, especially with the quality and pricing of kits that are vailable statesside (i.e. cooling mist, snow performance etc)

Sorry didnt know you done your own kits Chris, so cant comment on them.

The US kits are getting more advance with features like progressive controllers etc etc and a basic budget kit costing around £130 delivered.

 

One BIG factor often overlooked is that it benefits engines all power levels with its ability of Decoking and keeping carbon deposits to a bare minimum, ive been amazed how clean some engines have been that run WI when stipped down.

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In my mind most people do not really use WI properly.

 

A decent WI system using 50/50 water/meth hooked into the ECU to tell when there is a fault should enable you to run more boost, more ignition advance and lean the fuel mixture out.

 

All this added together should make a noticable difference.

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All this added together should make a noticable difference.

 

What difference does it actually make? Does it simply mean boost can be raised a little with less likelihood of det, or is it something that can be used for low boost applications too? (eg T67 at 1.2 bar)

 

Also, is ECU control essential?

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What difference does it actually make? Does it simply mean boost can be raised a little with less likelihood of det, or is it something that can be used for low boost applications too? (eg T67 at 1.2 bar)

 

Also, is ECU control essential?

 

There is a 'possible' way of getting an emanage to control the water injection based on boost levels...

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Here's an old post of mine on WI:

 

 

 

 

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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With the added cooling from the water and the increase in octane with the meths you can increase boost and ignition advance beyond what is normally acceptable, both of these two factors are very good for producing torque and power.

 

For proper use I would say map to it but then for what ever reason the water/meth is not injected you stand a high chance of blowing the motor, this is where you need safe guards in place on the ECU to lower the boost and retard the ignition.

 

 

As for the AEM you could use the nitrous maps, at the flick of a single switch you increase the boost target and run ignition and fuel correction maps to maximise its potential but you need a way to detect failure.

 

 

Most people when installing WI just use it to cool intake temps and activate it from a pressure sensor at approx 1bar as its alot safer and does offer an extra safety margin when pushing the motor.

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I have WI but have not reinstalled since the rebuild yet.... the thing that worrys me about mapping my car with it is if i have a problem such as pump failure of it runs out of water and i damage the engine.

 

Thats exactly my point, most people just use it in a fashion that doesnt really matter if it fails, which is fine and does offer more safety, but when used properly the gains can be much higher.

 

I am in the same boat as you.

 

Chris should hopefully be installing my WI in a couple of weeks but have only planned it as an extra safety margin and not to gain power with mapping etc.

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I have WI but have not reinstalled since the rebuild yet.... the thing that worrys me about mapping my car with it is if i have a problem such as pump failure of it runs out of water and i damage the engine.

 

There might be a way of fitting something like a washer bottle sensor and a dash light.

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Thats exactly my point, most people just use it in a fashion that doesnt really matter if it fails, which is fine and does offer more safety, but when used properly the gains can be much higher.

 

I am in the same boat as you.

 

Chris should hopefully be installing my WI in a couple of weeks but have only planned it as an extra safety margin and not to gain power with mapping etc.

 

Yea i think ill reinstall mine after all the mapping is finished... just as a bit of extra help.

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Great post Chris, that explains the benefits and reasons for WI clearly.. at least on an engine thats designed to deliver maximum power.

 

One thing thats not clear is why someone with a 'more than sufficient' fueling setup and map, plus running low boost on a 2JZ would require one. If the EGT and AFR measures are within safe limits then why add WI, surely there's no need?

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