Water Injection

After a failed attempt at DIY Water Injection on Beast when it had a JRSC I decided to try it again on the turbo system.

My Water Injection (WI) page will have three parts:
1) The installation
2) The tuning
3) An explaination of what WI does

I only recently completed the installation so the tuning section will have to wait.


I purchased a base level kit from
DevilsOwn for around $180. This was about $25 less than the normal price since I went in on a group buy with a bunch of guys on MiataTurbo.net, a turbo board I frequent. The kit contained a pump, a 3GPH nozzle, a relay, a plastic check valve, an adjustable pressure switch, some tubing and quick disconnect fittings. A wiring harness and crimp fittings were also included. The documentation was less than perfect but DevilsOwn says that they are working on it.

A quick trip to the hardware store to get some supplies. I think I paid about $20 for all of this:




The clear tubing didn't work out so I used some leftover heater hose that I had laying around. You can find hose like this if you go to your FLAPS and ask to walk behind the counter. Just look for something with a loop in it:



I wanted to install my tank and pump in the trunk. My trunk lid is held on by hood pins and it is a pain in the butt to get in there. I used the hole that was left over from the radio antenna as a way to fill my water tank from outside the car. I fill the tank by unscrewing the white cap and using a funnel:



I took the top off the gas can, cut the bottom off one of my hose fittings and glued everything together:









I drilled a hole in my gas can and screwed in one of the quick release fittings for the WI tubing. I used some silicon sealant around the fitting. The gas can is about 1 gallon and will be used as my water tank.:



I used the metal strapping to attach the gas can (my water tank) to the floor of my trunk by the battery and mounted the pump beside the tank:



The black heater hose loops around and attaches to the white cap that is sticking through the antenna hole. The hose is a little crimped but it works fine:



I drilled and tapped the elbow right before the intake manifold because I figured that would be the best place to inject the water. It turned out to be a mistake because the metal was too thick and the threads on the nozzle were not long enough. I ended up moving the nozzle upstream about a foot where it could be properly mounted. I don't believe this is the optimum place to spray the water but it will have to do for now. You can see a plug on top of the elbow where I had to patch my mistake. Note that the plastic checkvalve is about an inch away from the nozzle:



The pressure switch provided with the kit didn't really wasn't designed for easy mounting. I ended up drilling out a small hole that was on the switch and sandwiched it between two nuts on a stud under my dash:





I went to Radio Shack and bought red, yellow, and green LEDs with built in resistors and installed them in my control panel. The green LED is hooked up to the +12V line going to the pump and lights when the pump kicks on:



The pump is setup so it turns on and off (pulsates) and is supposed to keep a "constant" pressure. This doesn't work very well and I get fluctuations in the water flow and pressure. Since I don't have any experience with other WI kits I cannot tell you if it really harms anything. I measured the flow at atmosphere (no boost) and it was between 4.5L and 4.8L per hour.

Here is a
short video showing the pulsations while I was measuring the flow.


I will update this website as I start tuning the car. Tuning is my least favorite thing to do (especially since I seem to get my share of tickets while tuning on the open road) so it may take a while. Even though I have a never ending supply of free Methanol, I will probably stay with straight distilled water (which I also have a never ending supply of). My hopes are to get my car tuned, without the water, and then add water and start decreasing fuel. I think I can probably remove fuel until I start knocking and then add a little fuel back in. Again, this will take a while so don't look for quick updates on this.


Ok, a little explaination of what water injection does. If you have something to add or find fault in this please let me know (I am not an expert):

When increasing the boost level of a turbocharged vehicle, an undesirable byproduct is an increase in intake temperatures as well as a corresponding increase in combustion temperatures. These higher intake temperature increase the chance of detonation within the cylinder. Water injection decreases the possibility of detonation by lowering the combustion chamber temperatures and increasing the effective "octane" of the fuel. This allows the engine to run a higher boost and full spark advance without the use of race gas. As the water is atomized in the intake stream there is an additional cooling of the intake charge. Water injection also has the effect of "steam cleaning" the combustion chambers and exhaust valves. This removes the carbon build up that decreases efficiency and leads to pre-ignition (detonation). It will also keep the throttle body and interior of the intake manifold much cleaner than normal. Water is a byproduct of combustion and it is the chemical reaction of oxygen with the hydrogen freed from the hydrocarbon chains during combustion. How could the injection of water before combustion contribute further to the combustion process? During early combustion when the fastest reactions occur the effect of the water in the mixture is to cause a more controlled and stable flame front. The freeing of hydrogen and carbon to combine with oxygen has to work around the present water to form OH radicals and CO. By slowing this early combustion process there is further suppression of the potential for the mixture to burn too fast and contribute to knock. Later in the combustion process, slower and more complex reactions occur. The formation of OH radicals is very fast and interferes with the completion of the combustion process to form CO2 from the first step creation of CO. It is during this phase of combustion where present water helps to complete the slower reaction to complete the formation of CO2 since water is about the only way to complete the oxidation of CO. The additional present water actually speeds this reaction, which also happens to be when as much of two thirds of the energy from carbon combustion is released.