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Awhile back, I came up w/ a h20 injection system based on using an injector, pump, pressure regulator, and dual press switches. Check the link below for the intro. The design is based off the fuel injection system but it functions like the Aquamist system 2c.
http://www.saabnet.com/tsn/bb/performance/index.html?bID=38653
Setup for c900 using 20lb/hr(2.5bar) injectors w/ a 3bar FPR:
Nippon Densa 11.4lb/hr high impedance injectors from a ford festiva, shurflo 8000 100psi pump, adjustable pressure regulator set from 5-6bar, two psi switches (cruise control or overboost), and one high amp relay for the pump.
Well since the idea, I picked up a set of festiva injectors, a couple pressure switches, and a shurflo pump. The pump is a 8000 543 263 "on demand" pump w/ a 60psi switch that I picked up off Ebay brand new for 25$. The first task was to see if the injectors would atomize properly. During the initial design, I had someone say the injectors would only shoot a stream which was kinda discouraging. With all the commotion about h20 injection lately, I finally just got around to testing the injectors using a computer driven controller.
I found at the right psi(60+psi) those very small injectors will create an amazing conical mist (no stream) throughout different dutycycles. I haven't setup a pressure gauge yet so I don't know numbers but the pump came set at 60psi and I notice if I turn it down the nice mist turns more into a misty stream. The great part is that above 60 it works excellent and I only need it to work from 70-100psi. From the shurflo specs on the website, it says that the pressure switch is only adj from 45-60. I noticed that the on demand switch causes problems due to that the pressure has to reach 45psi before turning back on at which 60psi is reached. The 100psi pump specs show the switch has to reach 85psi before turning on. This will definitely effect flow volumes. For those thinking about making an injection system using this pump and just a regular nozzle you might want to consider a different head for the pump, one w/ an internal bypass so that there is alway 100psi available and no delay and more precision. I heard they make a pump head Model # 94-382-02 that has an internal bypass rated at 100psi.
For me, I think I'll be disabling the switch and using an external adjustable pressure regulator rated at 5-6bar(~70-80PSI), so w/ the system even w/ 20psi of boost won't go above 100psi.
From here, I'm going to get a pressure gauge to observe the psi and spray patterns then put it through some daily testing to see if the injector holds up using water. I'll also measure the flow rate of the injector using water to calibrate it to my calculations to figure out what exact regulator setting I'll need.
Seems like the system is coming together, total cost so far: $60
Will report later. I'll also try making a video clip of the injector mist using a web cam.
Theory and calculations:
H2O is recommended to be injected 20-30% of the total weight of the fluids
Density of gasoline = 0.71326 gram/ml
Density of water = 1gram/ml
20lb/hr(2.5bar)-->24lb/hr(3bar) times 4 = 96lb/hr(3bar) = 1008cc/min
1008ml x 0.71326 = 718.97grams fuel; If X is h2o g/min, then X/(719-X)=0.25, solved equals 240g/min.
240grams/min =240cc/min of water (23lb/hr)
But larger injector means less pressure so the smallest high impedance injector that I could fine was chosen: Nippon Denso 11.4lb/hr(3bar)
Using the 11.4lb/hr(3bar) injector would mean I need to run 23lb/hr divided by 11.4lb/hr times 3bar = 6 bar to provide the right amount of water to make h2o 25% of the total weight.
posted by 66.54.17...
OEM FI controlled H2O injection (original post)
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