pressure regulator

[JScoob]

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.

[mx5]

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

[JScoob]

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.

[Richard L]

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.

[JScoob]

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.

[Richard L]

How much volume of water are you planning to use?

[JScoob]

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.

[DuMaurier 7]

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 :?:

[slostar]

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

[Richard L]

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

[DuMaurier 7]

I did see your suggestion Richard , but I already have the 150 psi Demand pump , and I'm only seeing the internal bypass ones rated at 100 psi , also , using a regulator woulg give full adjustability and a 1:1 rising rate just like with the fuel system.

[Richard L]

You can get 125psi springs and the conversion kit cost less than 30 dollars. Nothing stopping ypu shimming the springs seat.

[DuMaurier 7]

So now I have to look for a sale for my pump ? :roll:

[Richard L]

you don't need to sell your pump, just order the by-pass add on - you just change the front part of the pump.

[DuMaurier 7]

Cool , I didn't know that I could do that , can you post a link ? , I'll look for it in the mean time.

[Richard L]

Cool , I didn't know that I could do that , can you post a link ? , I'll look for it in the mean time.

I believe the part you need is 94-380-38 - it is a pump head with by-pass. Make sure it comes with 125 valve springs.

Need to ring Shurflo directly for stock. http://www.shurflo.com

Richard

[NAnderson]

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.
Just wondering if any more has been discovered about using an EFI boost-referenced adjustable fuel pressure regulator with a water/alcohol injection system. I guess the biggest stumbling block would be the (much) higher base pressure and how the regulator would hold up to the increased pressures. Most EFI systems have a base pressure of ~43.5 psi and then rise 1:1 with boost from there. The water/alcohol injection systems would have a base pressure ~70-90 psi and then raise 1:1 with boost, ending at somewhere in the ballpark of 90-120 psi of water/alcohol pressure (boost dependent).

I've got an AEM universal adjustable fuel pressure regulator I'm going to give a go this year, but I'm somewhat apprehensive as to how it will react to the higher pressures, both base and absolute. We'll soon see.

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.
This is one area where the pressure switch on the Shurflo pump may actually come in handy! Let me expand.

You could wire the MPS to kick the pump on, completely bypassing the pressure switch on the Shurflo pump, so whenever the the MPS was tripped the pump would be constantly on thus activating injection. That you covered above. As for the pressure switch, you could wire that up to a switched 12V source so whenever the car was turned on the pump would run initially to pressurize the system but then turn off whenever it hit the set pressure switch point (probably 5-10 psi below the adjustable pressure regulator setting). Also, if during normal driving the system slowly bled down pressure the pump would automatically repressurize the system. Granted, there's a ~15 psi swing in the turn-on point of the Shurflo pressure switch, but it'd prevent the system from fully depressurizing and would automatically pressurize the system upon start-up.

Just a though...

[DuMaurier 7]

A friend of mine wanted to set up a WI system and offered me a good price for my pump so I sold it to him and I'm going to get the new Aquamist/shurflo 150psi internal recycle pump ..............just keeping it simple is always the best way :D

[NAnderson]

I'm going to get the new Aquamist/shurflo 150psi internal recycle pump ..............just keeping it simple is always the best way :D
That's a very good option and keeps things nice and simple. The only downside is that water/alcohol pressure won't increase on a 1:1 basis with boost.

I'm planning on running 30+ psi of boost and having linear water/alcohol pressure against manifold pressure is one of my paramount concerns. At 30 psi of boost a 100 psi pump would only be putting out 70 psi at the nozzle, thus greatly changing the flow rate. Not exactly what I want. Yes, it's a little more complex but my whole system is over-engineered so it just goes with the pattern. :lol:

Anybody else have input or suggestions on pressure regulators and water/alcohol injection? Still waiting for some of the big names to notice the forum is back online...

[fperra]

Couldn't you just pressurize the water tank with boost pressure?

[NAnderson]

Couldn't you just pressurize the water tank with boost pressure?
The fuel cell I'm using for a water/alcohol tank is in the rear hatch of the car. I'm hesitant to run a boost/vacuum line all the way back to the hatch because of the potential for a boost leak and I'm unsure how the fluid level sending unit would respond to pressurization. That, and I just had the AFPR sitting around and thought, "Hmm, let's try something..." :wink:

[Richard L]

you can try this:
(similar to a fuel injection system. But you have a run a non-by-pass pump.

http://www.aquamist.co.uk/forum/return-m.jpg