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Old 07-02-2011, 10:18 AM   #1
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Talking Water or meth through FI?

Alright, I have been doin some reading and searching and haven't been able to get the answer I was lookin for. This thought process was spurred on by jthowhat(?)'s forever alone thread. There are like two pages of him trying to justify why he bought the proefi, dude, just tell people to f off, you bought it 'couse it was what ya wanted... Anyway, with the features of this, all the inputs and outputs, a thought popped into my head. Has anyone run water/meth through fuel injectors? It would seem that you could have unlimited control on the WI through PW. with the flexibility of the ecu, you could do anything...
Thoughts? flames? If I am way off base I'll take the lumps, just curious.
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Old 07-02-2011, 10:25 AM   #2
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One word: corrosion.
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Old 07-02-2011, 10:39 AM   #3
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from what I've read like savington mentioned water will kill the fuel injectors super quick
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Old 07-02-2011, 10:39 AM   #4
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really? never considered that. I would not have thought that a methonal mix would have issues. OK, well, I guess that answers the question. lol
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Old 07-02-2011, 11:50 AM   #5
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You can do what you want by driving the pump with a PWM output and solid state relay. This will give you control over the pump speed which which in turn controls pressure and thus volume. Very common setup.
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Old 07-02-2011, 12:15 PM   #6
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Why bother?

Also, you dont inject pure meth, unless youre an idiot.
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Old 07-02-2011, 01:08 PM   #7
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Originally Posted by mousee View Post
really? never considered that. I would not have thought that a methanol mix would have issues. OK, well, I guess that answers the question. lol
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Originally Posted by Full_Tilt_Boogie View Post
Why bother?

Also, you don't inject pure meth, unless youre an idiot.
I AM an idiot, but that's another subject. lol


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Originally Posted by C. Ludwig View Post
You can do what you want by driving the pump with a PWM output and solid state relay. This will give you control over the pump speed which which in turn controls pressure and thus volume. Very common setup.
Yeah I know that, There are a lot of current ways of doing it correctly, I am aware. Just being curious. There are no new ideas and I am sure someone has thought of this already, so inform the inquisitive idiot...
I PERSONALLY feel that meth/water injection is a band-aid for tune and/or people being too cheap to buy good fuel...
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Old 07-02-2011, 03:19 PM   #8
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See my build thread. If I could do-over my meth/wi setup I would do it like this:

Fuel cell
Bigass Fuel pump
Fuel regulator
Some bigass injectors- 1000cc in the runners
Fuel rail
An lines
Fuel tank float to lift ground when I'm out of meth and toggle my trim maps off
something simple like a powercard to control meth flow (pwm) but I would control the injectors, not vary the pump speed.


Yes you can do things to deal with corrosion. You can also geth meth compatible parts. Yes, running 100pct meth will make a shitload more power than plain water. No, running pure meth does not make you an idiot.

Frankly, my top of the line meth kit is cheesy as hell. A standard fuel system would be around the same price and be robust.
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Old 07-11-2011, 11:36 PM   #9
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Quote:
Originally Posted by mousee View Post
I PERSONALLY feel that meth/water injection is a band-aid for tune and/or people being too cheap to buy good fuel...
Nothing to do with either really. First water wouldn't fix either of those things.. Meth is used for a cooling agent in setups, side effect being a fuel enhancer. That still has nothing to do with a tune. Infact untuned for it you would run rich.
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Old 07-12-2011, 12:29 AM   #10
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What the heck. Have to weigh in here. Especially now that I have actual experience with the subject matter.

I'm using WI instead of an intercooler and couldn't be happier with the decision. My WI is proving reliable and I have automatic failsafes in place should it ever have a problem. If you want to see how I did that, you can look at my build thread. Deleting the intercooler has the following advantages:
1. Plumbing is so much easier. Makes it more like a stock intake installation. No more hacking the car.
2. Far fewer joints in the intake.
3. A little bit less weight (although a diet would be more effective).
4. Less intake volume -- which may or may not give you sharper throttle response -- but probably does.
5. No intercooler boost drop.
6. Cooling capability of the car is enhanced rather than compromised. With an intercooler, you rob air that was intended for the radiator and AC condenser. With WI, if anything you are adding cooling capability because you are consuming a liquid that goes through a phase change and consumes massive BTUs to do so.

According to the original research and use of this technology, H2O is the way to go. Alcohol is used as an anti-freeze. Water is much more effective at cooling the combustion process, which slows the flame front (i.e., acts like a MUCH higher octane fuel) and allows for increased ignition timing leading to higher MBT. If an engine is purpose built for the water injection, higher CRs can also be used.

I originally thought that water would phase change and cool the air in my intake (much like an intercooler). In fact, I located my WI nozzle just after the turbo to try and maximize this effect. What I've discovered is that the water mostly stays in liquid form until it makes it into the engine (I only get about 2-3F of intake temperature drop with the water on -- which is far less than if all of the water phase changed). If you want to phase change the liquid in the intake tract, then you need to use alcohol. If you were doing pre-turbo injection, you definitely want a high % of alcohol.

Mind you, I'm running 10psi with WI and my failsafes drop that to 5psi automatically. I don't know that I would go more than that without an intercooler. Honestly, I wouldn't go more than that unless I had a built engine anyway, intercooler or not. My 1.6 is stock and high mileage. But, man, does it ever run nice with the turbo.
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Old 07-12-2011, 01:22 PM   #11
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Nobody bit on my "forget the intercooler" heresy? I'm disappointed.
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Old 07-12-2011, 01:30 PM   #12
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Originally Posted by hornetball View Post
Nobody bit on my "forget the intercooler" heresy? I'm disappointed.
I may get rid of mine pending a few test. If i get a massive pressure drop with it I will. If not there is only some small benifits to getting rid of it. I also have a fail safe but did it different. I have a flow sensor before the nozzle if the line doesn't see pressue I hit x amount of boost it will turn the boost down. I can run 10psi though without WI due to my intercooler. I can tell you that my intercooler works well I have a temp sensors before and after it. Working on getting a pressure sensor on both to do some logging to see what pressure drop i am getting through my IC. Like I mentioned if it sucks, I will just remove it. Also I can provide data that shows that meth is the better cooling agent then water in our application of use. I was convienced before I tried it that water would be the better cooling agent. However in the real world it wasn't.
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Old 07-12-2011, 03:57 PM   #13
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One more intercooler disadvantage . . . the hotter the ambient temperature, the less heat transfer it is able to generate (Heat Transfer = K x deltaT).

Heat transfer of water/alc injection is constant by mass injected no matter the ambient temperature.

Thread discussing intercooler pressure loss (i.e., boost drop-off): https://www.miataturbo.net/diy-turbo-discussion-14/suppose-i-fed-up-boost-drop-off-32479/

I might be posting in the wrong forum to get a rise from my intercooler heresy.
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Old 07-12-2011, 04:14 PM   #14
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Quote:
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One more intercooler disadvantage . . . the hotter the ambient temperature, the less heat transfer it is able to generate (Heat Transfer = K x deltaT).

Heat transfer of water/alc injection is constant by mass injected no matter the ambient temperature.

Thread discussing intercooler pressure loss (i.e., boost drop-off): https://www.miataturbo.net/showthread.php?t=32479

I might be posting in the wrong forum to get a rise from my intercooler heresy.
My car has 4 temp sensor connected. The location for these sensors:

1. Ambient just grabbing the outside temp.
2. intake filter, grabbing the intake temp.
3. post turbo but pre ic sensor (how hot it is before going into the ic)
4. post ic temp taken at the tb. (how hot it is after the ic if injection is on it also will show the temp for that)

My car is also equiped with pre-turbo water nozzle and post ic but pre tb water nozzle. Test that have been performed on it with it was 100% water and 50/50 meth. So at any given time we can tell you how effecient any of my parts of my car are. Since we know how hot it is outside how hot the air going into the motor is how hot the air coming out of the turbo is and how hot the air going into the motor is.
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Old 07-12-2011, 05:37 PM   #15
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Quote:
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My car has 4 temp sensor connected. The location for these sensors:

1. Ambient just grabbing the outside temp.
2. intake filter, grabbing the intake temp.
3. post turbo but pre ic sensor (how hot it is before going into the ic)
4. post ic temp taken at the tb. (how hot it is after the ic if injection is on it also will show the temp for that)

My car is also equiped with pre-turbo water nozzle and post ic but pre tb water nozzle. Test that have been performed on it with it was 100% water and 50/50 meth. So at any given time we can tell you how effecient any of my parts of my car are. Since we know how hot it is outside how hot the air going into the motor is how hot the air coming out of the turbo is and how hot the air going into the motor is.
Unfortunately, these sensors don't actually measure the performance of the WI. As I discovered on mine, no matter where you place the injector, most of the phase change of water happens in the cylinder. Alcohol will flash off faster with a great deal of the phase change occuring in the intake tract. This is why you "think" that alcohol is removing more BTU's than pure water. But, it's not.

To see the real effect of WI would require a bit more instrumentation such as a measurement of torque, fuel flow, liquid flow (alcohol or water) and EGT. But, hey, NACA already did that. No need to re-invent that wheel.
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Old 07-12-2011, 06:06 PM   #16
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Originally Posted by hornetball View Post
Unfortunately, these sensors don't actually measure the performance of the WI. As I discovered on mine, no matter where you place the injector, most of the phase change of water happens in the cylinder. Alcohol will flash off faster with a great deal of the phase change occuring in the intake tract. This is why you "think" that alcohol is removing more BTU's than pure water. But, it's not.

To see the real effect of WI would require a bit more instrumentation such as a measurement of torque, fuel flow, liquid flow (alcohol or water) and EGT. But, hey, NACA already did that. No need to re-invent that wheel.
I do not think you are completely incorrect, but if some phase change didn't happen in the IC the tempatures wouldn't change, but they do because the water and methenol have absorbed heat. I can measure the tempature of air going into my turbo and coming out and I can see a temps are different there from my pre-turbo setup. I can tell you that methenol changes that tempature drasticly as where water does make a change but less so. I also do not think water makes it through the turbo without a phase change, its just too hot not to phase change. Tempatures above 270. I can always do a quick run and try to take a IC pipe off and see if there is water in there however I do not believe it will be.

I think we have two very different goals. I want to reduce heat at my turbine compressor and cylinder you want to reduce heat at just the cylinder. Water can't achieve that for me because its absorbtion rate is slower. I can see my compressor effiency change more drasticly at the compressor with methenol.

Also those sensor do atleast tell me how well my IC is working for me.

Last edited by PatrickB; 07-12-2011 at 06:23 PM.
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Old 07-12-2011, 07:42 PM   #17
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I do not think you are completely incorrect, but if some phase change didn't happen in the IC the tempatures wouldn't change, but they do because the water and methenol have absorbed heat. I can measure the tempature of air going into my turbo and coming out and I can see a temps are different there from my pre-turbo setup. I can tell you that methenol changes that tempature drasticly as where water does make a change but less so. I also do not think water makes it through the turbo without a phase change, its just too hot not to phase change. Tempatures above 270. I can always do a quick run and try to take a IC pipe off and see if there is water in there however I do not believe it will be.
I really don't know where to start with this. It is a little bit difficult because the science and what you are measuring do not "appear" to agree. But that is not because the science is wrong, it's because you're not actually able to measure what you think you're measuring.

Anyways, here's the science:

The measured physical properties of the two liquids when they phase change to a gas are:

Methyl Alcohol: 473 BTU/LB
Water: 970 BTU/LB

So, given a mixture of air and one of these liquids, the effect of water going through a phase change will remove more than twice as much heat as methyl alcohol. That's simply a physical property. With our WI systems, the effect is even more pronounced because water is denser than methyl alcohol and our pumps work to inject volume instead of weight.

So far so good. But why, then, does the methyl alcohol change the temperature "drastically" while the water "less so" through your compressor? It's because far less of the water is going through a phase change. The water is remaining liquid . . . albeit in small droplets that hopefully aren't causing compressor blade erosion or pooling in your IC.

And why doesn't the water go through a phase change?

1. It takes time to go through a phase change. The time it takes is related to the density of the liquid as well as it's latent heat of vaporization. On both counts, water takes much longer to vaporize than alcohol.

2. Even if we had time for the phase change, air at any given pressure and temperature can only hold so much water vapor (or alcohol vapor for that matter). This is the field of psychrometrics. It is also related to Dalton's Law of Partial Pressures. Your actually familiar with the effect because you see it everyday in the form of rain clouds and water condensing on AC evaporator coils. Now, the starting point of the air makes a difference here. If you were to run your car in Phoenix, you would actually see a little more of an effect from injecting water than you do in Kentucky. That's because the relative humidity of the air in Phoenix is so much less. When it comes to the alcohol, typical air does not contain any alcohol, so it is eager to absorb it.

One other example of psychrometrics and Dalton's Law that you are familiar with is the radiator pressure cap. By keeping our engine coolant pressurized, we greatly increase it's boiling point. Your turbo compressor is (obviously) a pressurizing device. I hope you can see that the fact that your compressor outlet temperature is 270F really doesn't mean anything in this analysis. It's not as if water would boil at 212F under compressor outlet pressure conditions. Oh, that's another good analogy. Have you ever watched water boil? Takes awhile, right? Even once it's going. It's not like the entire pot flashes at once.

Anyway, dispensing with theory and getting to some useful bottom lines:

1. Water removes far more BTU by volume and weight than methyl alcohol. It is the best injection media if your goal is to cool the combustion process and avoid detonation or increase timing for more power.

2. For the most part, water is not going to vaporize in your compressor or intake tract. A little bit will, but most of that process will happen in your cylinder. This is another good reason to inject post intercooler if you're using water, as it is still in liquid form and likely to puddle.

3. Alcohol vaporizes quickly. If I were injecting pre-turbo, I would go 100% methyl alcohol. The temperature drop from the phase change of the alcohol in the compressor does good things for compressor efficiency.

Your ideal situation would be to inject 100% methyl pre-turbo and 100% water pre-throttle. Of course, now we're talking a whole second injection setup. Tail is starting to wag the dog.
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Old 07-12-2011, 08:19 PM   #18
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Yup I got it last go around but that clears even more up. I don't want to run %100 meth on my street car 50/50 is a pretty good compromise nor do I want 2 systems! Hehe. Thanks for the information man I appreciate it. Any particular books you have been reading or forums? I would love to be more versed. I am actually very intersted in removing my ic. I am less conservative I think then you I run 15psi on my stock 1.6 and I am going to give 20psi a shot.

Also can you speak on the merit of phase change pre tb. Seems like most ecu's run a 3d map based on air temp sensor at the tb. Thoughts?
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Old 07-12-2011, 10:57 PM   #19
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I've spent several hours trying to tune my WI system and I guess I'll report in some results. I could use some feedback too.

So far I've been running washer fluid which is 33% meth. I am running direct port injection with four nozzles which should flow enough for 500hp or so with a 15% ratio of mixture to fuel. I am boosting 19-25psi depending on ambient temperature (MBC FTL). Over 16psi I am spraying 80% max duty cycle which should be enough mixture for 400hp which is about all my turbo manifold can flow. I set up my AFRs to be around 12-12.5:1 above 9psi.

Results: I have NOT been able to get close to approaching MBT under 6000 RPM over 6psi. I've tried spraying a shitton of water at lower boost levels and RPM levels but I am I see occasional big knock. Interestingly, most of the time, the big knock occurs when I WOT in third gear when I'm at or above boost threshold. My WI system has a flow gauge and I can see flow occurring instantly, but I still get some knock. On big long 4th/5th/6th gear pulls, there is no knock.

Any ideas about this?

PatrickB I have not responded to your PM, sorry. I will be switching over to 100% meth soon and have two WI tubing splitters in the mail. The plan is to add two more nozzles to the system, one at IC outlet before the ATS, and one in the air filter for pre-compressor injection.
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Old 07-12-2011, 11:20 PM   #20
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Ford has a patent on mixing water with fuel for injection.
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