Wow that's a lot to read.
Omniphil, being unable to look outside my own box at times I aproach all fluid flow and pressure problems from a hydraulic guy point of view. The goal with your system being to hit the backside of a orfice with full pump capability instantly... If I read that right. 'you are using a pressure switch and not a progressive controler.'
Anywho here's my 2 cents worth...
1 cent... A check valve is not a bad idea, but a solinoid would be better. You are using fluid power to open a valve, and it is deducting from the amount of force that is seen on the backside of your orfice (nozzle). It does take measurable time to open that valve. granted is can be mesured in millaseconds only.
1.5 cents... there is resistance in hose. 4 feet of 1/4 hose will build more pressure at 5 gallons a minute than say 4 feet of 3/8 hose. But I don't think that this is your problem.
What the heck... I'll type it out in case someone wants to read...
The speed of Fluid flowing through a pipe is mesured in feet persecond. This is the velocity.
What comes out the other end is the volume of fluid. As it moves though the pipe this is the Flow Rate and is mesured generally in gallons perminute.
A large tube say will flow 5 GPM at a Velocity of 10 feet persecond. Where as a tube of same leangth one half the diameter will flow 5 GPM at 20 feet persecond.
Oh Yeah. And the measure of work being done or resistance in a system is mesured in PSI
2 cents... Most folk forget about the suction side of a pump, be it oil, water, liquified gasses... etc. There should be no vacum in the suction side. I think it was dvldoc who mentioned some place about the in-side hose from the trunk mount tank of a car being a larger ID. Vacum (anything less that atmostphiric pressure) can cause problems inside your pump where cavities of gas form and collaps inside the liquid. (ever see milky or foamy oily in a engine with a part clogged pick-up screen) This is called cavitation.
I placed my nozzle on the cold side pipe after the intercooler. As it was recommended to me by the WI guys to place it as close to the throttle plate as posable... But that's outside my box.
Cheers
John
