[theycallmeebryan]

The cheapest way people go about water injection is using the stock windshield washer reservior and pump hooked up to a hobs switch or contacter. This application only works for WOT or Boosted applications, and wouldnt really work for non boosted applications. This is because there is only 1 level of flow which you'd only be able to use at WOT.

For N/A applications, you need to have a map sensor tied to a controller to manipulate the voltage going to the pump.... so that its not 100% at 25% throttle position, for example.

Technically, you may be able to get by tapping off the throttle position sensor if your car has one. Or, just hook a potentiometer up to the carb and do it that way. Or perhaps use an electrical vacuum gauges and alter flow that way?