DIY water injection kit - How to

[s900t8v]

So I decided to make a water injection kit, something I thought would be beneficial, cost effective and fun to do.

This kit was not my idea, I saw the original thread over at autospeed.com but have added a few of my own elements to it. (water solenoid, flow valve, low level indicator etc)

The features of this kit!
Depending on the size of the injection nozzle you choose the pressure will be anywhere from 180-300psi (the smaller the nozzle the higher the pressure) - leading to good atomisation, the pump reaches pressure in 0.5s and doesn't cycle on and off but remains on providing continuous pressure/flow

All the parts for the cost about $150 AUD (the cheapest WI kit I could find was $230+$80 postage) so it's cheap compared to that.



It's fun to put together!


The potential downside - not sure if this kit can handle meth - the only questionable item would be the pump seals. I don't want to use meth, it's hard to get in aus and expensive.

Why not just buy a kit?!
Cheap water injection kits use a diaphragm pump, meaning the pump cycles on and off giving uneven flow/pressure patterns, these cheap kits don't always come with a check valve etc and can be pretty crummy. The other important point to make is that WI kit pumps are about $100-$200 depending on the quality (80-200psi) and that if your pump fails in your WI kit then you're out of pocket big time!

If you live in Aus (like me) the postage for a kit/spares etc is just too much to tolerate lol, plus most of the products the WI companies offer are cheap chinese items that have been restickered and marked up 200%

What you'll need!
- a broken PC power supply (makes a perfect case - with a cooling fan and everything, for the kit. you shell out the power supply components and mount your WI setup into it (ask a computer shop - should be able to get one for free!)
- a 12v - 240v inverter $15 ebay (150watt 50hz)
- an ULKA EX5 vibration pump $25 ebay (50hz 50 watt) (note the EP5 has a nylon outlet, and the EX5 has a brass outlet) I think the nylon might be weaker, but more compatible with methanol and vise versa)

- 3 relays $2.50 each ebay
- A Hobbs pressure switch $15 ebay


- an inline water filter (for the reservoir) $5 ebay (optionable) - I used a fuel filter, not sure if it will corrode, it's for ATV's etc

- a water reservoir (get one out of an old c900) $10 junkyard
- brass check valve with 25 psi or more cracking pressure
- injector nozzle $10-15 mcmaster carr
[IMG]http://i753.photobucket.com/albums/xx177/ejgrae89/Picture1-5_zps1a5c795f.png
3178K62
- low water level switch $5 ebay (optionable)

- wiring (cut some out of an old c900)
- electrical connectors - $5-10 local electronics store
- nylon hose + olive fittings $10-15

$150 AUD approx

You could DC diaphragm pump instead of an AC 240 pump which would also be fine, it would add probably about $60-$100 onto the cost. The advantage of using a DC pump would mean you would only need 2 relays, however you would have the pulsatile character of pressure/flow which probably doesn't help the ECU to calculate injection duties based on air intake temp etc (as it would be oscillating all the time) a proper recirculation pump may cost from $250-$400 (the ULKA pump in this DIY kit achieves the same flow characteristic as a recirculation pump).

The advantage of a DC pump is the ability to duty cycle the DC pump (or PWM it) I have seen a guy who programmed a microcontroller to control a DC motor driver through PWM to control the duty and therefore flow of a DC WI pump. This is what I want to try out eventually. But realistically speaking just getting water into the engine is enough to reap benefits, the flow control valve and boost pressure switch should give a reasonable amount of flexibility.

I put mine here, the charcoal canister is either getting relocated to behind the airbox in the engine bay or moved forward right up on top of the oil cooler. The cruise pump will sit above the water reservoir. If you have the APC here then what a perfect reason to switch to trionic 5.5 so you can remove the silly ign amplifier and APC box You could always get a smaller or better shaped reservoir and leave everything as is. I wanted to use the Saab one as it's huge!

Electrics setup! (I'll add a wiring diagram in later)

The advantage of using this AC pump is that the inverter won't draw more than 5 amps, this means that you really only need some pretty light gauge wiring, I've used 15A wiring as I like some lee way (and because I've set up a switched live on the left side of the car, it's nice to be able to have some switched 12v on the left side to add elec things to. You can get fused relays which make things easier otherwise add an inline fuse as close to the source of the permanent 12v as possible for safety.

So run a fixed live from the distribution block to the left side of the car to the input load side of relay 1.

Use a switched live on the switching side of relay 1 (I obtained this from the fuse box!) You now have a 10+A switched live for your WI setup.

On the output load side of relay 1 connect your water solenoid 12v+ and your inverter 12v+ (these devices will be powered whenever ign is on - also wire in the power supply 12v case fan to this circuit, this will keep everything cool)

The hobbs boost pressure switch will be used as a normally open circuit (closes the circuit at desired boost pressure) wire one terminal (NO3) to a ground point, and the other terminal (COM) to the earth of the switching side of relay 2. Provide the other terminal of the switching side of relay 2 with a switched live from the fuse box.

Run a light-medium gauge earth wire from a ground point on the chassis to the input load side of relay 2. From the output load side of relay 2 run the earth to the earth of the water solenoid, and the switching earth of relay 3.

We need a 3rd relay to trip the water pump on and off, because the inverter takes a few seconds to turn on/off we have to turn the pump on/off post inverter.

Supply the switching side of relay 3 with switched 12v (from fusebox) we have the switching earth from the load side of relay 2 (so when the hobbs switch closes it will close the circuit to the water solenoid, and to relay 3)

supply the input load side of relay 3 with either the brown or blue (load or neutral) wires coming out of the inverter output side. One of either load / neutral wires should be permanently wired to pump and the other will be switched by the relay. Wire the earth from the inverter straight to stand alone earth. This is just the safety wire incorporated into 240v AC systems.

For the low water level circuit all you need to do is install a LED in the car with a 12v+ feed and earth. Run the earth into the engine bay and connect the earth from the LED to the low level water switch, connect the other wire of the low level water switch to an earthing point on the chassis.

Additionally I am going to have my LED light up whenever the system is active. This is simple piggy back the earth of the water solenoid to the water switch circuit (on the LED side of the circuit) this way the LED will come on whenever water is being injected, but will also stay illuminated once the water gets too low.

I'll update again once more parts come from china and I get it finished. Now all that is left to do is to do the plumbing, and test sequences.

[s900t8v]

Getting it assembled








After testing the electrics side when assembling the components it might be a good idea to use a hot glue gun to stick everything down. I find that hot glue is also a great insulator so can protect sensitive wires etc.

If you're one of those people that uses crappy crimp on connectors (I solder all mine + crimp at the cost of time) a good trick is to shoot hot glue down the end of those crimp on connectors (I did this for further strength) this helps make them more water resistant, and stops the wire pulling it like it normally would out of those crappy connectors.

[peva]

I must have missed something here Ed, but what's the fan for and when do you activate it?

[s900t8v]

the pump is an ulka electromagnetic vibratory pump, the downside is that it creates a heap of heat and its duty cycle is only 2/1 minutes (on/off) it's actually the pump that pushes the steam out of expresso machines lol, super powerful and quick to generate pressure up to 300psi (depending on injector size) but yeah the downside is duty.

Realistically who boosts for 2 minutes straight though? the fan is probably overkill but it's just part of the computer power supply (it's the case fan) and seeing as it's 12v I thought why not hook it up.... it comes on with ign on (like the inverter as it takes a while to start putting out 240v) the boost pressure switch controls the flow of power to the pump.

Bought my nylon line and some brass olive fittings today, re tested the system with the lines connected (but no injector) and it really puts out! It looks like it's going to work just like the guys on autospeed said.!

[peva]

I thought it might be part of the stock case. My Aqua system is a pulse pump and it's heavily finned, but most of the heat sink is into the water, so there's maybe 1[FONT=arial, sans-serif]° temp rise max. Mine turns on at 10psi, so it only turns on when you got a bit of boost on. Pointless to do anything else unless you're using really cheap gas. I might add that I hardly ever see my knock LED on, even at over 1 BAR.
Hope the fan is quiet, otherwise it's going to drive you crazy.[/FONT]

[s900t8v]

ahah yeah how quiet is your desktop computer paul?! that case goes in the engine bay, not in the cabin, not gonnna hear anything once the car is running!!!

yeah those dc pumps are high amperage aren't they? I can imagine thye would generate some heat, mine pulls around 5a...

yeah well with this flow control valve I should be able to vary the amount of water so I can get benefit at lower boost levels. Plus with t5 its easier to map the fuel system to get the most out of the wi (lean off the fuel, advane the timing, up the boost etc)

[s900t8v]

Just an update of the water lines/fittings.

Waiting on he nozzle and then the kit will be ready for testing!

[Foreign Object]

In the late 70's (think gas crisis!) my family owned a VW dealership. We used to sell and install a water kit called the 'Turbo Vapor Injector'. I was young then and don't recall exactly how it worked but do know it was very similar, if not simpler than your design. Since then I have searched many times to find it's likeness with no luck until seeing your thread. Now my interest is renewed.
Many owners swore by the fuel savings.
Please update with your project success!

[s900t8v]

hey yeah i've got what I think is a fairly functional system at about 1/2 to 1/3 of the cost of a market kit...

I haven't tried it in the engine as I have to install it into an intake pipe but hopefully it works as intended - it definitely works well on the bench

[peva]

In the late 70's (think gas crisis!) my family owned a VW dealership. We used to sell and install a water kit called the 'Turbo Vapor Injector'. I was young then and don't recall exactly how it worked but do know it was very similar, if not simpler than your design. Since then I have searched many times to find it's likeness with no luck until seeing your thread. Now my interest is renewed.
Many owners swore by the fuel savings.

In the '50s, '60s, and even in to the '70s there were a plethora of devices that injected substances by intake suction into the inlet manifold of car engines. No turbos around that I knew of that needed charge-cooling. My father was of the opinion that cars always ran better on cold, humid or wet days. Whether this was true or not, there were many devices that traded on this and were designed to be fitted to the inlet of cars to inject water and other substances into the inlet to improve mpg, performance etc. Not exactly water-injection as we know it, but many people fell for it. I was too young to have an opinion on the matter. My dad, like me, knew everything worth knowing. There were even extractor devices to fit on the exhaust tail pipes to suck exhaust gasses out to improve performance. Then as now, there were plenty of suckers around. I seem to remember an extractor device fitted to his car. This is an ad for an intake device that I found in an old 1950s Motor magazine (SAD). Not exactly water, but the idea's the same. Note the high-tech fuel injection system.