Lets talk about water injection

[vrg3]

ciper - You mean that it would activate when throttle opening is high and vary duty cycle with manifold pressure or something like that? That's more or less what I meant in the post above, but I wasn't thinking of including mapping.

[ciper]

My idea would be easier and cheaper to build. It would be fairly tunable too, adjusting for pressure with a rrfpr for example.

[vrg3]

I'm confused -- what are you comparing your idea to?

[ciper]

To using more complicated electronics like injector driving ECU.

[vrg3]

Oh. I meant this:

But if you wanted to go a lot simpler you could just set up a little PWM circuit that used MAP sensor voltage as a control signal. All you need is some kind of function generator (sawtooth is ideal) and a comparator.