pressure regulator
 

Has anyone installed a pressure regulator to their WI system? I have this nagging feeling that there is just way too much flow and pressure variance, caused by both the pressure switch hysterisis and pump cycles.

I have been playing with both the shurflo and aquamist pump and I while the shurflo may flow more, I definitely don't like its pumping characteristics. The pump cycles are much slower than the aquamist and thus the system pressure swings detectably from some low pressure to 100 psi. I can literally feel my car surging in sync with the pump cycles. The accumulator merely delays the inevitable. So to fix that I'd need the 150psi shurflo + accumulator and a press reg set to 100psi - which should theoretically result in a constant 100 psi across the board.

Take a look at this site. Looks lik these guys make water injection system which works like a fuel system - it has a rail, a pressure regulator and a return line (so the water is flowing non stop). An article about water injection (history, etc.) there too. Even if you don't take that way it is still an interesting read:

http://www.rbracing-rsr.com/waterinjection.html

That site is a great reference point. I like their pressure regulator which is 1:1 tied to boost pressure. I just need to find a pressure regulator that is rated higher than 85 psi.

However, I don't see where they layout their overall design. For example, they mention you can't use fuel injectors, implying the need for controlling the amount of water injected, but their solenoid is a simple on/off, not a proportional valve like the HSV.

I am not sure if the 150 psi pump will cycle any faster, there is still the presence of the switch hysterisis. You have to use a "return to tank regulator" just like the fuel injection system.

Yes, I don't think the 150psi will improve cycle times. Its needed to maintain a constant 100psi via regulator - but I think this is just way too much work for improved flow compared to a priming pump + aquamist.

One things for sure, the shurflo pressure switch has to go. That 20psi hysterisis is terrible.

How much volume of water are you planning to use?

Right now I'd like to flow at least 550cc/min of water max. I think with the shurflo I'm hitting that intermittently, but again, I'm not entirely happy with the slow cycles.

Sorry to bring this old one back guys ,but I am also using the ShurFlo pump and I'm also wanting to eliminate the pressure swing problem caused by the integrated pressure switch . I am thinking of using an ordinary EFI adjustable pressure regulator to kick back to the tank and have the pump turn on/of when the MPS is activated @ 12 psi therby totally eliminating the pressure switch . After a bit of searching the only 0-200 psi EFI pressure regulator that I could find was the WELDON 2040 and 2047 , they are sold for $ 224.29 and & 318.57 respectively, a bit pricy , but they will get the job done.
One thing comes to mind though , By using one of these regulators , I will be trying to get my WI system to function like an EFI system with a continuous return , but remember that the EFI system runs CONSTANTLY , so that the system is always pressured making fuel available to the motor all the time , when the motor is shutdown however , the whole system DEPRESSURES ! , this would be bad for a WI system , since after periods of -injection there wouldn't be any residual pressure in the system because the regulator is open and bleeding the pressure to the tank , before the next injection event one would have to wait for the system pressure to build before any injection can commence , this can be very undesirable , and in a system like mine (with flow sensing ) , boost will never go past the WI treshold pressure set on the MPS ,since it will be limited by the DDS3.
To over come this , I am thinking of incorporating another normally closed solenoid into the system that will be wired in series with the pump , powered by the same relay . It would be located downstream the regulator but before the water tank . When the pump is switched off , this solenoid will immediately go closed and hold the system pressure , when the pump starts and the solenoid opens up , putting the regulator "on - line" allowing it to do its job and maintain the set pressure , what do you guys think :?:

sounds good, so: pump -> solenoid -> injector . with a tee just after the pump -> pressure reg -> solenoid -> tank ?

maybe use the pressure switch on the shurflo pump to switch the 2nd solenoid. that way the pressure will build up fast as possible. but may run into pressure spike problems if the pressure switch is set too high.

or

pump-> solenoid-> injector -> press reg & solenoid straight after injector -> return to tank ? although the 2nd solenoid after the pressure reg wouldn't be doing anything. since the pressure is just going to be lost out the injector. long as the pressure reg is installed right after the injector it should work almost as well. but wouldn't require the 2nd solenoid.

another way to do it is use a dc motor speed controler. adjust the motor speed to hold the pressure required. speed and pressure will vary slightly with supply votlage( unless you go for a more expensive controller) . but thats not much of an issue when the car is running. have disconected the pressure switch alltogether on mine (100psi shurflo pump). will run up to 130psi on my setup, but have it set to around 100psi, as i have no idea if it would be reliable at that pressure. hardly made it over 80psi with the pressure switch. built the controller from a kit for around 30 dollars

I have suggested using a shurflo pump with internal by-pass to solve all your water pressure problem many times, but no one seemed to warm up to the idea or noticed it.

Richard