Using rising rate regulator and misc tech. talk

[diymark]

Hey,

I'm turboing my Nissan A12 motor very shortly and am set on water injection to cool the air charge.

My initial intention was to use a 160psi pump to the solenoid/nozzle and as well as a rising rate fuel pressure regulator which overflows back to the tank. So basically the solenoid and nozzle acts as a "fuel injector" and the initial pressure is set on the RRFPR. Then the pump pressure would rise according to boost. So basically instead of staging nozzles I would run a "variable flow" nozzle.

Now heres my issue...water. How does it work in the cylinder? Is it just the fact thats its there in the combustion and it does its job regardless of the amount? (i dont think so) Or does the amount of water need to increase with either the increase of fuel or air?

I think it has a linear relationship with the amount of fuel (or maybe air?), so as the car comes onto boost the car flows x fuel in and y water, then further in the rev range, the car will start to flow 2x fuel then it needs 2y water in Is this correct?

Does anyone know what ratio rising rate regulator I would need?

Also I've read that you need 1cc/min flow per horsepower but this "ratio" seems very rough and generic to me - does anyone know how much cc/min water you need in proportion to how much fuel/min you burn?

Is there a percentage of the amount of fuel used that you add as water? Is there an A/F:W (air/fuel to water) ratio?

[keithmac]

People normally start at 15% of peak fuel flow (find out your peak injector DutyCycle and injector size to work out you maximum fuel flow).

I ran 15% in my supercharged Golf instead of an IC and it worked great, took some punishment at a few trackdays with no problems!.

[Howerton Engineering]

Yes, water is usually injected at 10-15% of fuel. So add your injector sizing up and pick a jet to suit.

I'm not sure of the dynamic range of your setup, but I'm not sure of all the hardware you are employing.