Markinter said:Your right F350camper
...Demand pumps will cycle on and off to meet a preset flow rating and by increasing the amount off back pressure required to cause the pump to cycle off it could flow more water through a nozzle thats rated at lower pressures.
Mark, fyi, the normal 'demand' pump cycles on and off to meet a -pressure- specification, not a flow spec.
Nozzles: the "flow" rating for a nozzle or injector is always spec'ed at a specific pressure. I.e. 1 gph AT 50psi, or whatever.
The flow from a nozzle will increase as the square root of the pressure applied. So if you double (times 2) the line-pressure from 50 to 100 psi, the 1gph@50psi nozzle will flow 1.414 gph (square root of 2).
fwiw, we've been playing with WI on our Jeep ZJ, because it started pinging after 160K miles. The WI does indeed appear to be stripping the carbon out; because it's stopped pinging now.
Also, on a recent trip to NV and back, we averaged 21.3 mpg; where it had been around 20.2. So about a 5% MPG improvement. Straight water, at 40psi from an RV pump, via some unknown nozzle that I pulled outta the junkpile here. Not sure of the flow-rate, but it's not much. It just seemed "about right".
Control was a dumb switch on the seat next to me. I'd turn it on whenever we were driving along; and shut it off when we came to a stop anywhere.
Just a hacked-together kludge for a couple of trips. Now I need to engineer a more sanitary and effective (and multi-stage) rev-2, and get it installed...in my spare time....between breaths or something...
Richard
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