Water injection: 1:1 boost-referenced/regulated water pressure

[psychlow]

Just found this interesting, thought I would share.

One of the problems with traditional water injection on turbocharged engines is that the requirement for the amount of water starts off low and increases as boost increases. On most systems, they're just set to activate a pump or an injection solenoid at x PSI via a Hobbs switch, and pump the same amount of water in regardless of the increase in boost.

The other day, someone on this board mentioned their theory of using a fuel pressure regulator to increase/decrease water line pressure 1:1 in relation to boost. I'd thought about it previously, but dismissed it as I was thinking that water running through an FPR would probably corrode it.

Yesterday, I decided to email Aeromotive about it.

Any of the Aeromotive universal bypass regulators, including the low
pressure 13204 and high pressure 13101, 13109 and 13105 are compatible with
alcohol fuels. There would be no issues with respect to the glycol, alcohol
or water in these units. Do NOT however use an Aeromotive in-line fuel pump
to handle water, this would result in immediate fuel pump failure. Good
luck and thanks for choosing Aeromotive!

Brett Clow
Aeromotive Tech Dept
5400 Merriam Dr.
Merriam, KS 66203
PH: 913-647-7300 ext 109
FX: 913-647-7207

-----Original Message-----
Sent: Monday, December 20, 2004 8:50 PM
To: [email protected]
Subject: Using your adjustable FPRs for water injection


Question - would using your adjustable fuel pressure regulators for a water
injection application corrode or otherwise harm the units? I'm planning on
using windshield washer fluid (49.5% distilled water, 49.5% alcohol, 1% blue
dye).

Thank you.

So, it looks like, at least with Aeromotive units, you could set up a water injection setup that would be boost-referenced. Set a Hobbs switch to say, 10PSI, and your base water pressure to 50 or so PSI. So if you're boosting 20PSI, water pressure would be 70PSI, but only 60PSI at 10PSI boost, etc. Then, just tune as needed.

Any thoughts? An optimal setup would use a MAF-metering method, but I'm thinking that this would be the next-best option and a lot less expensive.

 

[Mike000]

Doesn't the aquamist or the brass water injectors require at least 100psi to make the optimal fine mist?

 

[psychlow]

Doesn't the aquamist or the brass water injectors require at least 100psi to make the optimal fine mist?

I have heard that....

Does anyone know of a higher-pressure regulator that would work for this?

 

[psychlow]

The jet is made of nickel-plated brass with two spiral grooves cut into the centre insert. Water travelling through these grooves picks up a swirling motion before leaving the small hole on the tip, causing an atomising effect, turning the water into a fine mist: of course a pressure of at least 3 bar is required. Jet sizes from 0.5mm to 1.0mm are available in 0.1mm increments.

3BAR = 43.5PSI....

 

[ken inn]

a word of caution here. i dont think all the ww fluids use distilled water. for years i have been using distilled water, and in the winter, i used the blue stuff. i have an inline filter, one of those clear glass fuel filters with the disposable inner filter. after running a couple of gallons thru my system, the filter became clogged with mineral deposits, so badly that it stopped the flow of water. the filter did its job, but the deposits-calcium-like stuff that you see on showerheads-was so hard, and it was everywhere, i had to throw away the filter and get a new one. i now mix a small amount of denatured alcohol in the winter.

 

[psychlow]

Thanks for the heads up.

Yeah, I was cautiously optimistic about the quality of water in those washer fluids. You would think that in order to prevent clogging of the windshield washer system, they'd use distilled water, but perhaps not.

 

[16g-95gsx]

Another benefit from using a regulator would be prolonged injection capacitance. You would be able to establish a very high pressure within the accumulator, and inject a smaller pressure into the intake stream, thereby creating a larger pressurized reserve mass.

If you have the ability to regulate injection pressures to become linear with boost so that the differential pressure across the nozzle is constant, then there is no need to begin injection at such a high figure as 10psi, you might as well start it at a lower 4-5psi Id imagine. The air itself may not be heated enough to warrant injection, but the injection itself wouldnt cause the motor to bog, and any water particles that managed to get into the cylinder itself would aid in cooling the valves as well as the cylinder and piston top, creating a much less pre-ignition prone system by the time high boost and high rpms hit.

 

[Jehu]

Only problem with having a regulated system is that you have to have a return line going to your tank. Besides, using a 1:1 regulator in this application will only accomplish 1 thing...maintain the injected water amount independent of boost. For what you want to do you probably want something like a 1:2 and above regulator. Makes things more complicated, in my mind unnecessarily.

You have to remember that water isn't required for detonation suppression until you run the higher boost levels. So really, you don't NEED water until you are at full throttle and full boost. I know I never knock during non-WOT situations. If you're worried about pre-cooling the combustion chambers, just start injecting water a little earlier, or use a two stage system...

 

[nazthug]

snowperformance.net i the place that sells variable pressure water injection

check it out

 

[NDgsx]

Near the bottom of the page
http://www.rbracing-rsr.com/waterinjection.html

 

[Defiant]

Don't non-turbo fuel injection schemes use a variable pulse width (or frequency) instead of a pressure change? Why not use such a setup for water?

Oh, and for the water-suction I've run on the Datsun 2000 for years, I use an aquarium bubble stone for a filter on the intake in the tank.

 

[Jehu]

Don't non-turbo fuel injection schemes use a variable pulse width (or frequency) instead of a pressure change? Why not use such a setup for water?

Oh, and for the water-suction I've run on the Datsun 2000 for years, I use an aquarium bubble stone for a filter on the intake in the tank.

They do! Aquamist has that setup, and that's the only way IMO to have variable rate injection...it's a pulsed injection system. Only problem with that is that solenoid valves with a fast enough response time that can handle water are expensive. An additional injector controller isn't cheap either.

 

[Caithness]

www.alkycontrol.com

I've heard good things about these guys. I'm going to go with one of their kits when the time comes.

 

[Dallas J]

Im running the alky control set up on my Talon. I havent gotten too much testing with it yet though cause I have to get an alignment(changed my ride height)

What I have noticed so far is that, before I couldnt get knock to go away. It came on like real knock, and killed my power in 3rd gear. I think it was from carbon in the engine, but not sure.

Without really adjusting anything exept the turn on point (adjusted to come at a prescribed intake pressure), my knock stoped at 15-17psi. I was able to lean it out and get an 11.0:1-11.2:1 a/f ratio using a plx wideband. I had no know where as before with DSMlink set to zero across the board I had 5-6* retard in 3rd.

Ill get more testing done and do a full write up on it eventually.

-Dallas J