Water injection

[Blown353]

I run water injection, I bought the controller from Julio Don. His website is http://www.alkycontrol.com

It isn't the only option out there (there's also SMC, Aquamist, and others) but I have experience with Julio's unit and it's a well built and reliable piece.



A progressive controller is the way to go. You set the initial pump speed and pressure at which it turns on, then you set the ramp rate (how fast it increases pump speed as more boost comes in.) That way you can tailor the amount of water injected, rather than a single stage "on or off" system." For example, I have my controller starting with just a trickle of water at 3 psi of boost but at 15 psi of boost (my maximum) the pump voltage ramps up enough such that the pump runs just below the high-pressure cutout safety switch on the pump, and it delivers a LOT of water at that voltage. To adjust water volume delivery at the maximum safe pressure, I simply install larger nozzles. When the pump "bounces" off the high-pressure safety switch it pulses on and off and delivers water unevenly.

I'm using the controller in conjunction with a diaphragm pump from Northern Tool (about $60) that I re-adjusted the pressure limiting switch on to give about 140 psi. (The switch cuts the pump out at about 60 psi out of the box, and the pump will put out over 300 psi if you run it with the switch bypassed-- trust me!) The nozzles are filtered brass atomizing nozzles with integral filters from McMaster-Carr; I believe I'm running two M5 nozzles right now (that's 5 GPH per nozzle @ 60 psi.) The pump sucks through a fuel filter I found from K&N (clear plastic body with stainless mesh filter.)

One thing to keep in mind is that you will need solenoids if you install the nozzles under the throttle plates, as engine vacuum will suck water from the tank without them. If you install before the throttle plates, you don't need solenoids, but you'll still want to install the injection nozzles higher than the reservoir to prevent siphoning the tank dry. If the tank is higher than the nozzles, you'll need solenoids. I have my nozzles in the intake piping just after the supercharger and the tank mounted lower than the nozzles; this gets the solenoids out of the picture and makes the system simpler. Good solenoids rated for the pressure will run about $40 each.

There are REALLY fancy systems out there by Aquamist that have magnetically-coupled motor/pump combos and controllers with pressure-sensitive full feedback for clogged nozzles and signalling your ECU to revert to a "safer" map when the injection fails, but the system I pieced together is quite a bit cheaper and functions very well and has been reliable. Aquamist also has lower-end systems without feedback.

Water will pull out more heat from the intake charge than water/methanol or straight methanol, but the disadvantage is that it isn't combustible and you can't spray as much as a water/methanol or straight methanol mix. Too much water and you'll literally "drown" the spark out and kill the engine-- even at wide open throttle. Methanol will burn, so you can spray more before you run into problems. The disadvantage to running methanol is that it's corrosive to aluminum-- that means your intake, heads, etc.

I run straight water myself. I use distilled water to avoid hard water deposits / clogs in the pump, plumbing, and nozzles. The system has been reliable so far for just under 7000 miles. Just remember to fill the water tank from time to time! You can also put ice water or ice in the water tank.

NOTE: The "boost cooler" system posted above me uses the EXACT diaphram pump you can get from Northern Tool.

Troy