DIY water/meth injection- guide
 

After several considerations i have decided to go with water injection on my 02 bug wrx. Several reasons for this- not wanting the pipework and lag complications of a front mount, also i feel the benefits of a big top mount are not that great and you will still suffer from the dreaded heatsoak.
Also water injection will allow the use of normal unleaded fuel, a serious consideration with todays petrol prices.
I am a very diy orientated car tuner/modifyer and take great pleasure from doing all the work and experimenting myself, however this water injection kit would be an improvement on any turbo car, improving reliability and power outputs, giving an equivelent of 116 octane fuel.
The system will be simple and very similar to an entry level kit costing in the region of £200-£400, my kit will stand me less than £45.
A pressure switch actuated by boost pressure will switch on a high pressure pump in boost feeding a misting nozzle into the inlet of the manifold by the throttle body.
Considerations are;
Pump pressure and flow rate
Nozzle flow rate and ability to "mist" or atomize properly
the use of a non return valve
the pressure at which the system switches on at
Here is a picture of two switch options, one is a common oil pressure switch (tested with a midivac switches at a constant 6psi) the other is an RS spares adjustable switch, adjustable between 3-15 psi, In the pictures i am showing it being set-up to switch at 10psi, this is my preffered pressure- the car will be well into boost an no hesitation should be felt due to an excess of water for the conditions, also water injection i feel is not requred below this level.
Attachment 55638
Attachment 55639
Attachment 55640
Attachment 55641
The next consideration is that of a spray nozzle, it is very important that it mists the water and does not produce excessivly large droplets or even worse a jet of water. I hunted high and low on the internet and in diy/garden stores and could not find what i wanted here in the uk. the nozzle has to be "sized" for your engines power output and fuel consumption, the states was the only place i could find something.
Then i stumbled accross this by chance;
Attachment 55642
Connected it up to an empty CO2 gas bottle and half filled with water, drilled and tapped the other end to suit a PCL airline connection and added air via my compressor. the results were good, at a lowly 30-40 psi the nozzle atomized well, at 100 psi the flow and spray pattern was superb;
Attachment 55643
Attachment 55644
The nozzle i stumbled on was a .65 gal/hour danfoss pressure jet nozzle, available on ebay for around £6 delivered and available in many flow rates, from .55 to4 gallons and hour. So i bough a brand new one at my chosen flow rate and set about modifying it so it can be screwed in to my intercooler;
Attachment 55645
Attachment 55646
More pics to follow, next is the pump and supply pipe, i am using my washer bottle as a resevoir to save on space (they can share the same container)

Here is the pump i am using:http://www.ebay.co.uk/itm/Mini-45W-1...98508970857650

hoping it will be here today

A couple of usefull links related to water injection;
http://www.rbracing-rsr.com/waterinjection.html
http://www.turbomirage.com/water.html

Really enjoying reading this thread so far.

I dont want to modify my front bumper and love the idea of H20 injection.

Look forward to hearing more :)

Another option is to use a fuel injector for the solenoid and valve as it would have a good spray pattern

cool, ill keep the thread posted
Have a read of that first link above mate, it mentions the use of a fuel injector there, it works but only for a very limited period, and has to be drained every night to stop corrosion!

Quality job mate! Nice one! :thumb:

Interesting project :thumb:

Did you know about these ?

Aquamist Nozzle

might save some time machining up a nozzle adaptor.

nice link, but i have a solution now lol, and time is no problem when the whole thing is being made from scratch on a budget.
I did however see aquamist nozzle kit on ebay for £60, that was with check valve and some pipe, but i thought that was too dear and went with the heater nozzle.

Sorry its been a while, been sidetracked with other projects as you can imagine! Just finalised my waste oil burner for the garage ready for winter!
The pump has arrived and has been tested, making a good 120 psi no worries and a good spray from 50 psi upwards. I have modified the spray nozzle so it can now be screwed into the intercooler
Attachment 55647
I have also made a barb and check valve for the nozzle (pics to follow)
Here is the pump I bought for £26 delivered, 4 litres/minute 120 psi 12v 45 watt;
Attachment 55648
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Also modified the washer bottle pipe, by putting a "T" after the pump i can feed my high pressure WI pump, and the addition of a one way valve to the washers insures no air will be drawn back into my WI system;
Attachment 55650
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The intercooler is also off ready for drilling and tapping on the underside for the nozzle and pressure switch (Just about where the rubber pipe ends)
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Usefull link that made good reading for me;http://www.audiworld.com/tech/eng80a.shtml

Just remember the implications should the water injection fail be it through a blocked nozzle or pump failure. I presume the car is going to be mapped for the WI?

Ill see how i get on, I will be mapping the car. It is running without WI just now and i dont plan on running much more advance

Finished the check valve mister assembly today, also tested the whole rig with the pump, ill let the pictures do the talking;
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pump drilled and tapped for push connector;
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whole assembly;
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rigged up on the floor to test;
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working well;
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Ready to install into the cooler over the weekend! a relay and the pressure switch is all that is required to wire up to the pump, should make for some intresting tuning

Its all on and working;
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nozzle almost directly inline with and only a couple inches from butterfly throttle
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pump mounted

After a good tesy drive with the laptop, knock sensor, wideband AFR gauge all plugged in. I can honestly say the car performs no differently, the same afr, feels like same power, nothing has changed IMO. A rolling road session with and without WI may be an option to see if it makes a power difference, im sure i could now try running more advance if i wanted more power, but i can only assume the engine is much safer now with around 20% water to fuel going in the engine (and the occasional puff of steam on gear changes lol)

hi - stumbled upon this - fantastic project.

couple of questions

1) did you ever did the rolling road comparison? and subsequently try out a more aggressive tune (more timing/boost or both?) - if so what were the outcomes?

2) was there a noticeable difference in heat soak elimination with the kit on & off after experiencing the usual condition that give one heat soak?

3) most important for me - the positioning of the nozzle on the IC, was there a reason you offset it to one side?......... and if so, would there been an option to drill & taper at an angle (and not perpendicular to that flat surface) to face more towards the center of the flow/stream?

Thanks!

Never did any RR comparison, it's quite commonly known to allow for more timing and boost safely, so you can assume an increase in power and safety.
Was a long time ago, I'm sure you can put the nozzle anywhere you can drill and tap a hole. Has to be post Intercooler though. Four injectors (one for each cylinder runner) are ultimately best.

we reckon the W/M gives about +25hp and corresponding torque,that's mapped in, also helps spool. That's on a car running mid 400's using a TMIC.
My system will only allow the car to run wastegate pressure if there's a fault, low flow due to a blocked jet etc, or it isn't switched on, so it's not possible to run advanced and do damage.
My system is Aquamist, so expensive.
It has a big impact on intake temps and I could see it being very useful in hot climates or were fuel quality wasn't good.
Also keeps ACT'S down when high speed running on track which can be a problem when using a top mount.
Trev

Hi there

As above WMI usually give around 20bhp,in our case we are gained 15bhp in hot weather mapping,on torque I think we are not gained so much

Here are results

V-power only(99RON)

https://cimg0.ibsrv.net/gimg/www.sco...4dd53c1277.jpg

Tesco 99 and 50/50 WMI

https://cimg2.ibsrv.net/gimg/www.sco...ce79effd74.jpg

We are run AEM WMI,which I think is overpriced and if its worth the money,I just don't think.if you are looking for more power,meth in tank is way to go

Heat soak elimination not sure,I'm still not convinced by WMI,what I've logged on drag strip in very hot weather(30c) I've seen drop in ACT around 10C which is not a lot

Hope this helps

Thanks,Jura