legacycentral bbs

I plan to use it on my car. Why dont you?

Did a google for "Water injection" and turned up many good sites including
http://www.rallycars.com/Cars/WaterInjection.html
http://www.turbocalculator.com/water-injection.html
http://www.mgcars.org.uk/mgcc/sf/sf100108.htm

Interesting.

I"m not enough of a wrench monkey to figure out how to set this sorta thing up.

So is it pumping water constantly after a certain point or do you press a button when you want it?

Another great article on this @ Autospeed:

http://autospeed.com/cms/article.html?&A=0115&P=1

I'd pretty much rather do this than a stupid intercooler.

I was going to try and make mine activate only under WOT and boost after a certain RPM.

This is something i'd really be interested in doing, because the only drawback i can see is that you'd need to keep the tank populated with fluid. I don't know what you'd do in the winter, but i suppose there's some solution to this in places where IC sprayers are used.

Wouldn't you want an intercooler as well to get the power gain? It said that with an intercooler you get a power gain but with just the water injection you don't necissarily get that.

ciper wrote:I was going to try and make mine activate only under WOT and boost after a certain RPM.

I think ideally you'd want to have it mapped by load (manifold pressure will do) and RPM, kind of like fuel injection.

I'll see if I can get my brother to join this thread; he's done a lot of reading on water injection. There's a lot more to it than simple cooling of the intake charge. If done right, it changes the combustion chemical reactions. I remember him once describing a particular situation in which someone reduced the amount of fuel injected by 50%, injecting water instead of the other half of the fuel, and safely made more power in the end.

You are correct, but this is harder to do.

What would happen to a fuel injector if I used water?

I don't know. My brother was gonna try using a Jaguar fuel injector (the kind with a barbed feed) but he hasn't implemented it.

Ideally I'd have it tuned to the throttle position sensor. Anything above say 75 percent activates the water injection.

Mark,

My friend has had a water/methanol injection system on his Talon for almost a year now and loves it (so much that he has gone through 2 transmissions because of it). It really allows you to tune your car for more power without worrying about detonation (unless of course you run out of water/methanol. He actually injects windshield washer fluid into the intake because of the methanol already mixed in that. I wouldn't recommend doing that, i would get a pure mix. He also uses an old fuel injector for it. He has had problems with this setup because of failing injectors. This happens because when you trigger the injector, it is immediately opening to 100% of its duty cycle which decreases the life of the injector significantly. He also has it setup to trigger when the boost goes over 12 psi. This was done with a simple pressure sensor purchased at NAPA auto parts for about $20. To pressure everything, an old Talon fuel pump is used in a returnless system. Again, this is not recommended as it seriously pressurizes the resevoir and can spray eye burning and horrible tasting windshield washer fluid over anyone looking at the engine when this happens (trust me on this one....). I plan to create a modified version of this system for my car this summer. One thing i forgot, to keep the methanol/water from destroying the fuel pump, Marvel mystery oil is added weekly to keep the bearings lubricated.

Good info, keep us updated on your progress.

very good topic
i think water sparying will save my motor, i am just in the process of building a water sprayer for my car. what i was doing before was spraying water on the front of the intercooler and it helped out a bit.

i have a cold start injector that is going to spray water in the motor should i spray after the intercooler or before?

who makes a system that i can bye from, or just use a toggle switch.

thanks nuwand
you still going to school in my city. i got to show u my car as soon as the pistons get in from subaru i will be back on the road.

The more I read up on it the complicated it seems to make a good proprtional system. Anyone can fab up a jimmy rig system, but to self build a good system its quite difficult, especially the elctronics part. You need something that monitors manifold pressure while proportionally variing the input power to a pump. And at the same time the flow of water to the nozzle has to be tunable, too much and the motor will bog, too little and there will be no benifit.

Mark,

Instead of controlling the pump and the flow to the nozzle, I think it makes more sense to treat water injection like fuel injection. Have a pump pressurize the supply (if it's before the manifold it can be fairly low pressure) and use a regulator with a return line. Then use an injector that you pulse width modulate.

Do you have any ideas on the circuitry required to make such a miniature control unit. I really need to learn the fundamentals of electronics for all the things I want to make. Waht kind of regulator would you use?

Mark,

I don't know what kind of regulator you would use... Is it possible that a fuel pressure regulator would work?

McMaster sells a variety of pressure regulators and pressure regulating valves. They're kind of expensive though.

It may even be possible to make your own regulator. You would essentially just need to make a large ball-and-spring relief valve. The pretension on the spring would control the amount of pressure built up at the inlet.

There are lots of ways to build the control circuitry... The most flexible (and probably expensivest) way to go would probably be to use an aftermarket programmable ECU to drive the injector(s). But if you wanted to go a lot simpler you could just set up a little PWM circuit that used MAP sensor voltage as a control signal. All you need is some kind of function generator (sawtooth is ideal) and a comparator.

Hope I don't sound like a broken record, emanage this, emanage that...I don't feel I know enough about it, I'm uncomfortable with piggyback stuff generally...but I wonder if you could use the emanage extra injector map that can drive two extra injectors and has a 16x16 map for them....perhaps that could be used for water injection control? or nitrous...or jello, salsa, guacamole....You could use that to start water injectors up according map or maf vs rpm...I sorta thought throttle figured in their too, but I'm not sure. Maybe you can set up a load setting that is map or maf and throttle = load and then a load vs rpm map , not sure about that though. And then use the timing map to advance timing if you can when under water injection....
I'm sorta talking out my ass I guess. Their is a tuning shop near where I live that is offering a two day course on fuel injection tuning, where they set up a system and tune it on a dyno. I probably won't be able to do the one coming up, but the next one I hope to.

Micum - Yeah, an e-Manage could be a pretty good way to do it in my opinion. That's what I meant by an aftermarket programmable ECU. An e-Manage is kind of a weird cross between a piggyback and a standalone ECU.

NICO I WRX U wrote:thanks nuwand
you still going to school in my city. i got to show u my car as soon as the pistons get in from subaru i will be back on the road.

Hey Nico, i'm not going to school there anymore, but might be going back in the near future. I'd still like to see your car. Actually i ran into a guy this week who told me his friends brother in hamilton had some crazy legacy like mine. I asked if it was you and seems like it is. Pretty small world i'd say.

I still venture into hamilton every once in a while so maybe we can meet up when the weather gets better.

very true it is a small world. everyone has some good ideas about that water injecting.

You electronics guru can come up with the part numbers, but tell me if this would work.

Two reference voltage.

When one is at 4+ volts the curcuit is active

The other voltage is variable, from 3.5-4.5

At 3.5 volts the OUTPUT of the circuit is 25/50 12 volt pulses per second
At 4 volts the OUTPUT is 36/50
At 4.5 OUTPUT is 40/50

Then make the voltage to pulse mapping adjustable. Change line pressure as needed to gain correct flow.