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      09-28-2012, 01:39 PM   #1
shiv@vishnu
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Exclamation Tech: Water vs Alcohol injection

Thanks to radar1 for finding this on the Buick Grand National forum (they have been doing water/meth injection for decades):

"Alcohol injection and water injection should never be compared to each other. Water is able to remove a lot more heat than alcohol,but it must be injected into a much hotter environment to do its job. The good news is that the compressor gets very hot. The Buick community doesn't see this fact as an opportunity to extract more power. If your going to inject an alcohol water mix,this is the only injection site that woks.

Injecting an alcohol/water mix at this location becomes less effective as you increase the amount of alcohol. Alcohol can't work its magic in this environment. It's too hot.

If you inject an alcohol/water mix after the intercooler and before the throttle body,it becomes less effective as you increase the amount of water. Water can't work its magic in this environment. It's too cool. 100 percent alcohol works the best in this location.

Another reason you can't compare the two is because alcohol is a fuel that adds octane and oxygen to the mixture.
I've seen people respond to threads about the fastest cars on 93 octane who are injecting alcohol. A motor running on 93 octane and alcohol injection isn't producing its power with 93 octane. When you inject alcohol you increase octane and oxygen.

Comparing these two liquids is not even like comparing 93 octane gasoline to nitro methane.
Water does things that alcohol can't do in one environment.
Alcohol does things water can't do in another environment.
Put each of them to work for you in their respective applications,but never compare them."
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      09-28-2012, 01:43 PM   #2
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Interesting post, dumb question, but is there any room for useful water injection on our platform?
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      09-28-2012, 01:47 PM   #3
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Shiv, does this make any of your recommendations change as to what mix we should all be running, given that we have a safe setup?

It would seem to me that the recommendation would be little to no water given where most of us are injecting. Am I interpreting this wrong?
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      09-28-2012, 03:01 PM   #4
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Maybe we inject water (hot environment) close to turbo and meth as usual ?
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      09-28-2012, 03:04 PM   #5
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That's the way I read it. 80 or 90% is probably a good start if you're injecting in the chargepipe. The method of injection also makes a difference, since atomization is an important function. The Vishnu PWM kit comes with 2 1.0mm nozzles and runs at 160psi. If you need more methanol volume, it would be prudent to increase the number of nozzles, not the size of the orifice, to ensure the mixture is adequately evaporated before the manifold. The Aquamist HFS4 is pretty much the same system, IIRC, so no worries about poor atomization from a variable speed pump.

Additionally, I have been toying with the idea of moving the nozzles to the cold side of the IC, which gives another 18 inches or so of distance to mix and evaporate. Problem is, I have a stock IC for now. Plastic can be drilled and tapped to M8x0.75, right?
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      09-28-2012, 03:49 PM   #6
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These are my thoughts:
Assuming good distribution, I would think vaporizing in the cylinder is best. And all meth/water will vaporize eventually, so closer to the cylinder the better, **IF you can distribute the mix evenly between cylinders**. I think atomization and location is most important for distribution (and for the IAT sensor), and for this reason more upstream is better typically, but we are wasting some of the cooling effects.

The reason higher water content produces less power is because it takes up space that could be used for combustion components fuel and O2.
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      09-28-2012, 04:38 PM   #7
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Quote:
Originally Posted by Joshboody View Post
These are my thoughts:
Assuming good distribution, I would think vaporizing in the cylinder is best. And all meth/water will vaporize eventually, so closer to the cylinder the better, **IF you can distribute the mix evenly between cylinders**. I think atomization and location is most important for distribution (and for the IAT sensor), and for this reason more upstream is better typically, but we are wasting some of the cooling effects.

The reason higher water content produces less power is because it takes up space that could be used for combustion components fuel and O2.
Wasting some of the cooling effects by upstream placement doesn't matter, since you can always spray more meth for more cooling assuming even distribution across the cylinders and big enough meth tank for your road course.
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      09-28-2012, 04:58 PM   #8
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IMO E85 does such a great job with cylinder temps that it would make running 100% meth a much more feasible idea (fire hazards notwithstanding)
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      09-28-2012, 05:07 PM   #9
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IMO E85 does such a great job with cylinder temps that it would make running 100% meth a much more feasible idea (fire hazards notwithstanding)
Even at just a 50/50 mix water/meth is flammable. I've seen WW fluid burn and that's normally 30-40% methanol. IMO ANY methanol mix should be treated as if HIGHLY flammable.

The links provided on the OTHER site universally suggest 100% meth is the way to go and if the meth system can support it that's what should be run. Even so I run a 50% mix just because my local M1 supplier only gets in shipments every 3-4 months and I don't want to run out.

Last edited by Ænema; 09-28-2012 at 05:12 PM.
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      09-28-2012, 05:21 PM   #10
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Quote:
Originally Posted by Ænema View Post
Even at just a 50/50 mix water/meth is flammable. I've seen WW fluid burn and that's normally 30-40% methanol. IMO ANY methanol mix should be treated as if HIGHLY flammable.

The links provided on the OTHER site universally suggest 100% meth is the way to go and if the meth system can support it that's what should be run. Even so I run a 50% mix just because my local M1 supplier only gets in shipments every 3-4 months and I don't want to run out.
The point is 100% methanol will be much easier to ignite than a 50-50 mix.
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      09-28-2012, 06:29 PM   #11
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If anyone runs 100% they should be trunk mount only. Going above 50/50 on a WW meth solution is a fire waiting to happen... And from my personal experience, it will.
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      09-28-2012, 06:31 PM   #12
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the way I see this is that you should inject 100% meth after turbo and 100% water pre turbo. The pre turbo water injection is something we need to explore as a platform, I posted in a thread a while back about pre turbo water injection as RX7s and buicks have had great results with injecting pre turbo. I think there is some top end we can get out of the stock turbos by doing this, maybe 30-50whp more on the top end if this can be dialed in properly. I've been dying to try something like this out its just that the recommended mounting location of the high atomization nozzles is at the turbo inlet and mounting there in our cars is a Bitch

http://www.e90post.com/forums/showthread.php?t=332729
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      09-28-2012, 07:10 PM   #13
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Pre turbo injection is used on large GE gas turbines to increase there efficiency by out 10% or so. Here is a tech paper a PHD mech engr student at a Japanese university doing testing on small turbos and found he could increase efficiency by 7% and lower temps at outlet of turbo from 45-90*F effectively lowering the work the turbo does. The catch to all this is not injecting too much and also making sure you get a really fine mist. Seeing how far we go into the very inefficient range of our stock turbos at 17-20 psi, I think the increase in efficiency may be much greater than 10% because it will pull the operating point to the left on the compressor map and the efficiency lines get closer together as you go right (exponential relationship of efficiency vs flow/pressure ratio).

http://www.esi.nagoya-u.ac.jp/h/iset...1224Nguyen.pdf
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      09-28-2012, 07:34 PM   #14
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At this time I only know one member spaying pre-turbo and he's running low 11's with stock turbos. I think he's spraying meth and water. He's also running 100% e85. It would be interesting to see the dyno numbers with and without pre-turbo injection.
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      09-28-2012, 09:22 PM   #15
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Quote:
Originally Posted by themyst View Post
IMO E85 does such a great job with cylinder temps that it would make running 100% meth a much more feasible idea (fire hazards notwithstanding)
I didn't realize E85 did much to reduce cylinder temps. It thought it was most advantageous simply because of the higher octane.

I wish it was common in my region.
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      09-28-2012, 09:57 PM   #16
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I didn't realize E85 did much to reduce cylinder temps. It thought it was most advantageous simply because of the higher octane.

I wish it was common in my region.
That's where the benefit of e85 comes from. It dramatically reduces combustion chamber temps making pre-ignition less likely to occur. Thats where the difference in octane and effective octane comes in.
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      09-28-2012, 10:28 PM   #17
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Quote:
Originally Posted by Joshboody View Post
These are my thoughts:
Assuming good distribution, I would think vaporizing in the cylinder is best. And all meth/water will vaporize eventually, so closer to the cylinder the better, **IF you can distribute the mix evenly between cylinders**. I think atomization and location is most important for distribution (and for the IAT sensor), and for this reason more upstream is better typically, but we are wasting some of the cooling effects.

The reason higher water content produces less power is because it takes up space that could be used for combustion components fuel and O2.
ALL of the methanol wont always vaporize.
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      09-28-2012, 10:29 PM   #18
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Quote:
Originally Posted by Joshboody View Post
These are my thoughts:
Assuming good distribution, I would think vaporizing in the cylinder is best. And all meth/water will vaporize eventually, so closer to the cylinder the better, **IF you can distribute the mix evenly between cylinders**. I think atomization and location is most important for distribution (and for the IAT sensor), and for this reason more upstream is better typically, but we are wasting some of the cooling effects.

The reason higher water content produces less power is because it takes up space that could be used for combustion components fuel and O2.
ALL of the methanol wont always vaporize. You want it to vaporize before it enters the cylinder, too.
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      09-29-2012, 01:06 AM   #19
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Originally Posted by ///M 95 View Post
ALL of the methanol wont always vaporize. You want it to vaporize before it enters the cylinder, too.
Are you saying 0.001% could somehow escape and survive the high cylinder temps?
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      09-29-2012, 01:11 AM   #20
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I love the power increase with my meth setup.... Meth elbow in trunk tank/pump setup

What If hook up another pump n tank inthe trunk running water injection(on track days ice/water mix)..... Would it be worth it???
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      09-29-2012, 01:29 AM   #21
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Quote:
Originally Posted by Randomaccess335 View Post
I love the power increase with my meth setup.... Meth elbow in trunk tank/pump setup

What If hook up another pump n tank inthe trunk running water injection(on track days ice/water mix)..... Would it be worth it???
Hardly. Log your IATs to see if you need more cooling.
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      09-29-2012, 08:24 AM   #22
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Quote:
Originally Posted by Randomaccess335 View Post
I love the power increase with my meth setup.... Meth elbow in trunk tank/pump setup

What If hook up another pump n tank inthe trunk running water injection(on track days ice/water mix)..... Would it be worth it???
I honestly doubt the benefit would be worth the hassle, unless you just happened to have a second kit lying around. Even then it's still a second system to worry about having issues with.

If you did, I wouldn't use ice water. The cooling effect doesn't come from the temp of the water, it comes from the heat energy removed by the water evaporating when it is injected.
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