Water Injection Install

UPDATED 2-22-06


The spare tire covers the washer fluid reservoir and a vast amount of space.

The washer fluid reservoir and water pump all fit on one side.  This allows you to use the other side for whatever else you might want.

The water exits the reservoir through the front windshield washer pump and split at a T-fitting.  By tapping into the front supply line, I do not have to make any new holes in the reservoir and it is already designed from factory to pull the water from the lowest point in the container.  One side continues onto the front washer nozzles and the other feeds the water pump.  Before the water enters the water pump it is filter by a simple see-through fuel filter.  After the pump, is the water hammer (pressure accumulator), water pressure gauge, and the 1/4 NPT to 1/4" barb fitting.  From there 1/4" poly hose travels along the drivers side following the factory wire harness through the steering boot and into the engine compartment where it attaches to a small manifold.  The manifold split the water into three paths: two for one HSV each and the third is for a future intercooler sprayer.

UPDATED 2-22-06:    If I were to do this again, I would install a bulk head fitting between the two washer fluid pumps.  As it is setup now, I get leakage from the hood washer fluid nozzles after boosting the car.  Which is very annoying if you just washed your car and now you have huge water spots on the hood of the car.  Something like kimyeelai's setup on the DSMLink forum, which is explained in this thread.  If you do not have access to the DSMLink forum, then look at the bottom of this webpage.

The water hammer, shock arrestor, accumulator.

The T-fitting taps into the water line running from the front washer pump.  On my car the front washer pump has a black rubber hose and the rear washer pump has a clear hose.

Close-up shot of the simple 1/4 vacuum T-fitting.

I order a 1/4" check valve from McMaster, part #7757K43. This was to prevent the water pump from drawing in air through the front washer nozzle line.

I am using the Aquamist HSV with the FIA2 to control the water flow.  The FIA2 is installed along the driver's side of the center console.  In the back ground my Tech Edge WB02 and 400amp inverter can be seen.

Here you can see the water junction in the engine compartment.  1/4" poly water line is run from the trunk to this junction.  The water is split between the water injection and intercooler mister systems.  The solenoid on the left of the junction feeds the intercooler misting system.  The two brass fittings feed two HSV (High Speed Valve).  Each of those HSV's supply two nozzles each.  There is a total of four nozzles currently running on my water injection system.  Since I am using the Aquamist HSV, I only have one stage.  When the system activates all four nozzles are running.  As the fuel being consumed by the engine increases with RPM, the water increases flow to match.  In this system the water to air/fuel ratio stays constant.

NOTE:    There are cheaper alternatives to water flow control, but remember things are cheaper for a reason.  Although the other controllers say they are "progressive" they are really only semi-progressive.  You CANNOT progressively control fluid flow through a pump by regulating the voltage.  There is NOT a linear relationship between voltage and pump flow.  The ONLY way to control the fluid linearly is with injectors AND a pressure regulator like the fuel system.  The alternative is the Aquamist HSV and FIA2 combination.  With the HSV/FIA2 the flow is as close to progressive as you can get without designing a hole new fuel system.  The only part it falters at is regulating pressure to the nozzles.  So, the transitional period between system activation and full boost is not perfect because as the boost pressure increases the fluid pressure does not increase.  But the HSV/FIA2 system is still keeping linear injection rate with the fuel injectors, so it is not a huge discrepancy.  Since you HSV/FIA2 system is designed around your injector size, once you reach full boost, your fluid injection IS linear and progressive.

The new direct port injection setup.  Two HSV's feed four 0.6mm nozzles.

UPDATED 2-22-06:    I have since upgraded my fuel injectors from 950's to 1600's.  As a result, I needed to increase the water jet's to four 1.0mm to keep the correct percentage of water/methanol and fuel.

Updated Notes/questions 4/03/04

2r99gst wrote on 04-03-2004 18:19:
I really like your WI setup and I am considering mimicking your setup (if you don't mind), if I do decide on doing WI.

The only question that I have is the wiring for the FIA2. I want to also use the FIA2/HSV instead of a simple on/off condition for the WI without varying amounts of WI. A constant water:air ratio is definitely the way to go.

My question is where did you have to wire the FIA2 to? It's being driven off of the injector signal, correct? So just a connection to one of the injectors?

Also, how are you activating the system? Are you using a pressure switch, DSMLink FPRS controls, or something else?

I was looking at this diagram:





Please feel free to copy me. That is what us DSMer's do.  I did not think of this all by myself.  I had a lot of help,  Brad at George's Imports will atest to this.

Note: Run a 1/4" line from the trunk to the engine compartment. Less pressure drop when the system is operating with the big ShurFlo. And it is much cheaper at OSH 0.12$ per/ft.

On the FIS2/HSV set up with the Surflo pump. There are only 5 wires that matter. Red, Brown, Black, Blue and green.

The green one is hooked up to the #1 cylinder drive signal for the ECU. I tapped in for this in the engine compartment, but sicne then I have thought about the "best" wiring. You should tap the line at the ECU, Then you will have less connections in the engine compartment. Use the Vfaq to find out which ECU pin it is.

Blue goes to your trigger for the system, I am using a boost switch, but you can connect this to your FPR. The choice is yours. If your going to hook it up to the FPR, then find the correct pin at the ECU and connect there.

Black is Ground.

Brown is the trigger wire for the HSV. Connect it to the HSV.

Red is your power wire. You must connect it to the FIA2 and HSV.

Any questions? E-mail me


PS. When using the HSV, you will be able to run much more water than others simple because your delivery is much more efficient. I have found that instead of finding the misfiring point, you will find the diminished returns point. So be vigilant in your tuning and monitor your 60-90 times. When they increase dramatically and you cannot tune them back at the same boost pressure you have hit your limit.


Parts List From Washer Fluid Reservoir To The Engine:

This is for my specific application.  You do not have to do it this exact way.  Take what you like ignore what you do not like. (EXAMPLE: Like only one HSV is really needed to run two nozzles)

  1. 1/4" T-fitting: to tap into the existing water line exiting from the front washer fluid pump (Kragen)
  2. 1/4" Check valve (McMaster part #7757K43) : used on water line feeding front washer nozzles, so you don't suck in air from that line.
  3. 1/4" Poly hose (OSH)
  4.  Fuel filter with 1/4" hose barb ends (Kragen)
  5. 1/4" Poly hose (OSH)
  6. 1/4" hose barb to 3/8" NPT male fitting (OSH)
  7.  ShurFlo water pump your choice
    a)    8000-343-236 SHURflo All Viton (I used this one because it was cheap, and just turned up the pressure on the pump to 100psi)
            1.2 GPM open flow, Viton valves, Viton diaphragm, 60 PSI Demand Switch, 3/8" NPT-Female ports.   
    b)    8000-543-238 SHURflo High Pressure (This seems to be the favorite pump of WI users)
            1.6 GPM open flow, Viton valves, Santoprene diaphragm, 100 PSI Demand Switch, 3/8" NPT-Female ports
    c)    8030-813-239 SHURflo High Pressure (Some people like to run higher pressure, I do not because the Aquamist products are designed for 100psi)
            1.5 GPM open flow, Viton valves, Santoprene diaphragm, 150 PSI Demand Switch, 3/8" NPT-Female ports.
  8. Various bolts to mount the pump in the trunk (OSH)
  9. 3/8" male to 3/8" female 90* fitting (OSH)
  10. 3/8" NPT nipple (OSH)
  11. 3/8" NPT T-fitting => Plus fittings necessary to add pressure accumulator (water hammer)  (OSH)
  12. Water Hammer: Sold in the US as the Watts Series 150A Water Hammer Arrestor 1/2" (part #0269503)
    DYMATIC, INC. Sells them for 14.99 on EBay Sells them for 32.69
    Sold in England as the Micron Shock Arrestor at
  13. 3/8" NPT nipple (OSH)
  14. 3/8" NPT T-fitting ==> Plus fittings necessary to add pressure gauge (OSH)
  15. Pressure gauge (OSH)
  16. 3/8" NPT male to 1/4" hose barb (OSH)
  17. 1/4" Poly hose run along the driver side under the door threshold up through the steering column rubber boot. (OSH)
  18. 1/4" hose barb to 1/4" NPT male (OSH)
  19. 1/4" NPT T-fitting ==> Plus fittings necessary to add IC water sprayer solenoid (OSH)
  20. IC water sprayer solenoid (Power Aire part #52J8DGB-12VDC; phone number 800-526-7661)
  21. 1/4" NPT nipple (OSH)
  22. 1/4" NPT T-fitting (OSH)
  23. 1/4" NPT nipple X2 (OSH)
  24. 1/4" NPT female to 1/4" NPT female 90* elbow X2 (OSH)
  25. 1/4" NPT to 1/8" bushing X2
  26. 1/8" NPT to 4mm push-loc fitting X2 (McMaster part #5449K111)
  27. 4mm poly hose X2 (Aquamist or McMaster)
  28. HSV X2 (Aquamist)
  29. 4mm poly hose X2 (Aquamist or McMaster)
  30. 4mm push-loc T-fitting X2 (McMaster part # 5449K131)
  31. Water nozzle X2: size depends on your particular system (Aquamist)
  32. M8 x .75 tap is need to install the nozzles.  A cheap one can be purchased from, part #EP5040080 for $3.95.

Parts List For The Electrical Installation Side:

This is just to give you an idea of how I wired my system.  IT IS ONLY A GUIDE.  I am not responsible for any problems you may have as a result of following my example.  I COULD BE WRONG.  Make sure to double check all manufacture  instruction before connecting any wires.  If you have never dealt with electrical wiring before, have someone else install this for you.


  1. 12-14 gauge wire run from the battery into the rear compartment to a fuse (RED WIRE IN DIAGRAM)
  2. 15amp in-line fuse
  3. 12-14 gauge wire run from the fuse to #30 connection on the relay (RED WIRE IN DIAGRAM)
  4. General 4-pin relay
  5. 12-14 gauge wire run from the #87 connection on the relay to the water pump positive terminal (BLUE WIRE IN DIAGRAM)
  6. 12-14 gauge wire run from the negative terminal on the water pump back to the negative terminal on the battery or any good ground (GREEN WIRE IN DIAGRAM)
  7. 18 gauge wire run from an ignition source to the #85 terminal on the relay. (ORANGE WIRE IN DIAGRAM)  This wire will supply the power to trip the relay and allow electricity to flow to the water pump.  You may just want to hook this up to an ignition wire or you may want to run it through a toggle switch so you can turn on/off your water pump.  The toggle switch is a good idea just incase you run out of water/meth, so you can turn off the pump and avoid destroying it.
  8. 18 gauge wire run from the #86 connection on the relay to the same ground used for the water pump. (GREEN WIRE IN DIAGRAM)

  9. Since this is a home made water injection system and much of the Aquamist system in NOT used, many of the wires on the FIA2 are also not used.



Bulk head fitting installation

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  #26   Add to kimyeelai's Reputation   Report Bad Post  
Old 12-08-2004, 22:22
kimyeelai kimyeelai is offline
Join Date: Apr 2002
Posts: 151
kimyeelai is off the scale
This is how I tapped into the windshield washer tank...with a bulk head fitting. Taking the pumps out allows me to manipulate the nut to fit onto the bulkhead fitting.

The pump set-up.