We did a quick video to show you why all Labonte Water/Methanol Injection system come standard with a Fluid Control Solenoid - INSTANT RESPONSE RATE. While other systems have nothing or check valves, without a solenoid you are still going to get fluid drip and puddling in your intake. Once the pump signal stops all the line pressure will bleed out into your intake without a solenoid. A check valve will still bleed fluid until pressure drops below the opening pressure.
The video also shows that a solenoid placed too far away from the nozzle will have no effect. We did this test as some have posted install photos of the solenoid located in the trunk by the pump as recommended by the "experts" - bad idea.
Our entire line of VC series methanol injection controllers have also been updated with a second +12V output channel designed to control a solenoid or NOS relay. This simplifies install wiring and no need to tie in solenoid to Pump PWM wire resulting is instant response rate from the system.
http://www.youtube.com/watch?v=UQx3pT6TgiM