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Old 07-21-2015, 04:37 PM   #1
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Default Using a fuel injector as a nozzle

I plan to make ~230whp without an intercooler on my 1.6

Obviously i need water injection to keep IATs down. I have decided to inject water only, pre compressor.

Is there anything stopping me from using a fuel injector for flow control? I have heard that water rusts them shut but if i use an EV14 which i believe has stainless internals i should be immune to this?

The plan is to piggyback the water injector from one of the fuel injectors in the rail, which should give me a water flow rate proportional to fuel flow.
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Old 07-21-2015, 04:47 PM   #2
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<p>
Quote:
Originally Posted by sparkybean View Post
I plan to make ~230whp without an intercooler on my 1.6 Obviously i need water injection to keep IATs down. I have decided to inject water only, pre compressor. Is there anything stopping me from using a fuel injector for flow control? I have heard that water rusts them shut but if i use an EV14 which i believe has stainless internals i should be immune to this? The plan is to piggyback the water injector from one of the fuel injectors in the rail, which should give me a water flow rate proportional to fuel flow.
</p><p>&nbsp;</p><p>Most decent water injection kits inject at a MUCH higher pressure than fuel injectors are designed to handle. Like, triple.&nbsp;</p><p>&nbsp;</p><p>EDIT: That is, triple the max they would be reated for. ~300psi.</p>
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Old 07-21-2015, 05:00 PM   #3
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Hmm. Reasons? Atomisation?

Surely a fuel injector doesnt have problems atomising fuel, so if i run water through one at, say, 100psi, surely this would do it?
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Old 07-21-2015, 05:02 PM   #4
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I'd be worried less about pressure (I agree with your reasoning) and more about the long-term effect of a water / methanol mixture on the innards of a fuel injector deigned for petroleum / ethanol blends.
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Old 07-21-2015, 05:03 PM   #5
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Why not just fit an intercooler.
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Old 07-21-2015, 05:05 PM   #6
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Fuel is much more volatile than water. Also, you are injecting it further upstream. I would say that you want to do whatever possible to atomize the water as well as you can.

I understand the effects of pre-compressor injection, but Ive seen some evidence that the water can actually damage the thin leading edges of the compressor.



I dont think its worth it.
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Old 07-21-2015, 05:34 PM   #7
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Why not just fit an intercooler.
Because i'll **** in your mouth.


Compressor damage is still a big worry for me. I remember reading that volvo tried pre comp injection in the 80s and it killed a turbo after 80k miles. Thats a ton of mileage, but knowing volvo thats probably pushing 5psi boost and with tiny amounts of water.

Any more info on that pic?


Did a bit of googling on the EV14, found this PDF. Seems methanol is okay, ish. Water only may be the answer.

Last edited by sparkybean; 07-21-2015 at 05:44 PM.
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Old 07-21-2015, 06:10 PM   #8
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Cold **** could be you're answer either.
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Old 07-21-2015, 06:20 PM   #9
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Normal EV14s do not have all-stainless internals. Let E85 soak in an ID1000 and it will eventually corrode. I shudder to think what a normal OTS EV14 would look like after a few months of pure water.

This is not a good idea.
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Old 07-21-2015, 06:34 PM   #10
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A boost based WMI kit is about $280...not expensive enough to warrant rigging something up IMO. Run a nozzle post turbo with water or washer fluid and see how your BAT's are. They'll likely be A-OK
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Old 07-21-2015, 06:37 PM   #11
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I'd keep it simple if I were you. If you plan to only inject water, then inject it post-turbo with a regular old nozzle. Running water through the compressor doesn't help it vaporize because the air (especially in the UK) already contains a lot of water and when you raise the pressure of the air its ability to hold water actually decreases (given constant temperature -- look at psychrometric charts). With the temperature rise through the compressor, it ends up being a wash -- in general, the water stays in small droplets until the combustion event no matter where it is injected.

Alcohol is a different story. That can be injected pre-compressor effectively and a good portion of it will phase-change and absorb intake heat. It also doesn't eat compressor wheels like water. But it's overall capacity to resist det during the combustion event isn't as good as water.

Rest assured that if fuel injectors could be effectively used for this, they would be. Also, I'd be stunned if you can make 230 on a 1.6 without an intercooler. I managed about 190 targeting 10psi -- which is about as far as you can safely push it with water injection/no intercooler. I'm currently fitting an intercooler on my silver car to make things even KISSer.
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Old 07-21-2015, 06:53 PM   #12
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Injectors | Magneti Marelli

Quote:
The injector has a stainless steel body, a fuel-resistant plastic connector, martensitic stainless steel internal valve and an electromagnet with a low carbon content stainless steel armature.

...

Benefits
Suitable for use with Methanol
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Old 07-21-2015, 06:57 PM   #13
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I love it when people overcomplicate things in the name of simplicity
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Old 07-21-2015, 08:24 PM   #14
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The whole PWM of the pump setup is so simple and proven. I see no problem with it.

OP,
I like your plan to run just water. Let the EMS control fuel, you dont need to add any to your water injection. I would recommend adding a little touch of something to prevent algae bloom though. Like a little splash of alcohol.
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Old 07-25-2015, 08:53 AM   #15
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Tons of useful, usable advice.

Joe, Brain, Sav, thanks. I am now hunting for an IWP injector, they seem to be OEM fitted to a few renaults and fiats so should be a simple ebay buy. Ive believewater flow rate needs to be between 20-40% of fuel flow rate so ill size my cc/min accordingly.

Im loathed to just have a nozzle with on/off flow. If im going to do this I want to have my water flow perfectly tuned at every RPM and load, not have something that is perfect at 3krpm then gets progressively leaner as rpm/boost rise. You could do this with pump PWM im sure but i only have a microsquirt and im sure as hell im not the one to program those curves into a microcontroller.

Hornetball, full_tilt, ta for the words of wisdom. Nice to know that ill get close to my goals at least. I cant help but think that if i injected pre compressor i could run straight water and have even stonger anti-det protection than water/alky mix. That is my motive for this, i dont see the need for meth/alky if you can stop the turbo heating up the intake air in the first place, rather than trying to cool it down after its been heated. Good shout on keeping things sterilized, maybe a shot of russian standard every once in a blue moon would do it..

I picked up a Aquatec 4l/min 8bar pump and lines yesterday, i suppose i should update my build thread.

Last edited by sparkybean; 07-25-2015 at 11:13 AM. Reason: not knowing what i just bought
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Old 07-25-2015, 12:04 PM   #16
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Quote:
Originally Posted by sparkybean View Post
That is my motive for this, i dont see the need for meth/alky if you can stop the turbo heating up the intake air in the first place, rather than trying to cool it down after its been heated.
You're not getting it. Not in the least. And you're not listening.

Water injection works to suppress detonation in the cylinder. It is a very ineffective intake air coolant -- no matter where you spray it. Doubly so in humid England. You can't phase change if the air is already saturated. That's why it rains so much in jolly old England after all.

Alcohol can cool the intake charge some, especially if sprayed prior to the compressor. But it's a less effective detonation suppressant.

Very old technology that the vendors are happy to misrepresent. The term "chemical intercooling" especially makes me laugh. If you're going off what you're reading on vendor websites, just remember, they want YOUR money.

I've attached some real reading.
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File Type: pdf naca_H2O.pdf (959.2 KB, 174 views)
File Type: pdf NACA_H2O_2.pdf (454.4 KB, 153 views)
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Old 07-25-2015, 03:08 PM   #17
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Okay. Ill take a bite or 2 out of some humble pie. Thank you, hornetball. Theres tons of conflicting info out there, but those pdf's look like a freaking goldmine. I need to sit down and absorb.
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Old 07-25-2015, 03:15 PM   #18
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Quote:
Originally Posted by sparkybean View Post
Okay. Ill take a bite or 2 out of some humble pie. Thank you, hornetball. Theres tons of conflicting info out there, but those pdf's look like a freaking goldmine. I need to sit down and absorb.
I've done WI on my SC setup (3 stage setup), it was pure water. It sort of works. It does work. But it didn't work as well as I needed it to. I was running very high water/fuel ratios, 30-40% by volume and 20+ PSI Boost on pump gas. I don't run water injection any more.

My suggestion:

1. Install an intercooler
2. Install an intercooler
3. Install an intercooler
4. Consider E85.

Even if it's a tiny intercooler, it will help a lot.

If you do end up running WI, use water/alcohol or water/meth, not just pure water.
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Old 07-25-2015, 06:37 PM   #19
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Originally Posted by patsmx5 View Post
If you do end up running WI, use water/alcohol or water/meth, not just pure water.
Meth (methyl alcohol) is an alcohol. ??

Unless you're talking methamphetamines. But I think those cause detonation rather than suppress it.

Water injection worked well for me with the exception that I wasn't disciplined enough to come off track when my low water light would come on. That's operator error.
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Old 07-25-2015, 06:43 PM   #20
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Quote:
Originally Posted by hornetball View Post
Meth (methyl alcohol) is an alcohol. ??

Unless you're talking methamphetamines. But I think those cause detonation rather than suppress it.

Water injection worked well for me with the exception that I wasn't disciplined enough to come off track when my low water light would come on. That's operator error.
Methanol, ethanol, something besides pure water only.
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