Water Injection, what mix/ratio of methanol should be used? - Dodge SRT Forum
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post #1 of 21 (permalink) Old 08-21-2009, 06:38 PM Thread Starter
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Water Injection, what mix/ratio of methanol should be used?

Many WI users ask about what liquid to use for water injection or more specifically what ratio of water and methanol. The thing that I would like to stress is water......is does an excellent job of intake air charge and in cylinder cooling. With regards to WI, to me methanol is an additive to the water not the other way around.

When the typical WI user first looks into mixing, methanol looks to be the substance to use and in a large amount because of its octane value. True methanol adds octane but the reason for water injection in the first place is because water does much better then fuel in cooling, remember methanol is a fuel. Intake air charge and in cylinder cooling is what the water injection user is after not additional fuel. The WI user is typically adding methanol so as to use the properties of the methanol to help promote flame speed via methanol's octane value, a little has a desirable effect.

Methanol mixed with water in a ratio of 50/50 is still in a relatively safe state, after a 50/50 ratio, the WI system and the water injection supply tank needs to be thought of as an auxiliary fuel injection system = additional safety concerns should be applied.

Some points about fluids

* Distilled water, because of mineral deposits or hard substance contamination are the enemy of water injection users, distilled water is preferred over tap water. The fluid being used should come from a sealed container. Distilled water is low cost and easily obtainable.
* Washer fluid, typically contains about 35% methanol this is the simplest solution to get methanol into you're WI system..more often then not 35% methanol is an ideal mixture for most users.
* Methanol, added to either washer fluid or distilled water. This can be purchased straight up from race shops or garages that sell fuel to racers.

Other additives have been used, but these will be addressed in another thread = this thread should be solid information for most new WI users to rely on.

Some info on methanol http://www.methanol.org/pdf/FuelProperties.pdf

EDIT: http://www.methanol.org/pdf/MethanolMSDS.pdf see bottom of pg 3
http://cetc-varennes.nrcan.gc.ca/fic.../2004-125e.pdf see pg 2

EDIT: the National Fire Protection Association's code states that over 25% methanol in water is deemed a flammable substance.

The following charts are calculated based on:

10Kg of air, Gasoline's latent heat capacityof 350KJ/Kg
Water's latent heat capacity of 2256KJ/Kg
Methanol's latent heat capacity of 1109KJ/Kg

Injection water at different ratio to fuel at 100% water and 75% Water/25% Methanol. You can see the at 100% water injection, only 3% of w/f fuel ratio is enough to replace 2.5 point of a/f ratio (dotted line). As soon as 25% of Methanol is added, the a/f ratio is dropped to 12.0 - loosing some cooling capacity



Each of the following chart show a 25% percent increase in Methanol concentration of the mix.



lastly, just methanol is added and no water. The chart on the right is 100% water



The two charts show (first and last) will require you to inject twice the amount of methanol to equal the latent heat of water alone. Methanol is relatively low cost and very effective as a coolant so what is the problem?

When a higher concentration of methanol is injected, you need to lean your engines a/f ratio to accommodate the extra fuel or your engine will bog down and loose power. Consequentially you run the risk of putting the engine into heat stress if the supply of methanol is suddenly interrupted. Injecting water does not affect the a/f ratio. It appears that 50/50 mix has the best of both worlds.

In either cases, having a good WI system with reliable "system fault" diagnostic capability is essential, this is especially true if you are running a high concentration of Methanol. I have not taken the account of the fueling properties of methanol.



"Water and methanol injection does the same job in different ways, they both perform in-cylinder cooling and knock suppression well. Since water has a higher latent heat value than methanol, you need to inject twice the amount of methanol by mass to extract the same amount of heat during combustion. This is why all pure alcohol injection systems require a bigger jet, you need to inject 2.5 times by volume more than water. This makes little difference in practice except you need to find a bigger container.

Effect on knock suppression is totally different:
Water suppresses knock by quenching peak flame front temperatures hence regulating the frame propagation speed ? (too fast burn promotes knock). In-perfect charge distribution produces lean and rich pockets. Lean pockets burn at a higher temperature (oxygen-rich = faster) compared to fuel-rich pockets (excess CO slows down burn speed).

Alcohol suppresses detonation by increasing the knock threshold value of a given fuel grade. Since large amount of alcohol is required to control in-cylinder temperatures, air/fuel ratio will be affected significantly. Some fuel has to be removed to avoid over-rich mixture.

Power producing potentials:
In theory, more power will be produced if more charge is jammed into the combustion chamber, resulting in higher cylinder pressure and temperature. In practice, the associated components such as pistons, turbo turbine, etc has a finite operating temperature constraint. This is normally reflected by the EGT. The general accepted EGT figure is about 900C.

Power is basically a force exerted onto the piston per unit of time. Force (pressure) is generated with heated air in a confined space. If cylinder pressure can continue to increase without temperature rise, we have the ultimate power plant. Water injection and alcohol injection will be a good tool to perform this work, lets examine this in more details how each concept can help achieving this.

POWER TUNING:
(Assuming we have a powerful ignition system, a strong engine and unlimited supply of air and fuel).

For water: the task is relatively simple. First generate as much heat as possible by adding more boost and fuel. Water is then injected to absorb the excess heat until EGT is within a permitted safe level. Overall BMEP (Brake Mean Effective Pressure) is now increased due to the vaporized water. The amount of BMEP increase will depend on the mechanical strength of the engine structure. Water?s ability to push the power capability is almost unlimited.

For methanol: First consider using methanol as a fuel instead of Gasoline. Methanol?s ability to increase power is confined to the knock threshold, and available heat to increase the BMEP of an engine. Methanol has only about half of the energy content of gasoline, so twice as much methanol has to be injected to produce the same power. As twice the amount of liquid has to be injected, the cooling effect is huge, resulting in over-cooled combustion chamber, limiting the BMEP. A 100% methanol engine has to use multi-spark ignition system to ensure the mixture is constantly being re-ignited due to the cold combustion chamber. Within those constraints, there is still huge potential of power increase.

A good compromise to inject a percentage of injected into a gasoline engine. This will ensure good inlet and in-cylinder cooling effect, but how much? From reading many results form various forums, it appeared to be between 10-30% to fuel. Unfortunately, the results were not consistent, some got excellent power increase, some experienced engine knock, some misfires and some with very low EGT. Why?

4-5 years ago, AI system was very basic, at a certain manifold pressure, the pump starts and deliver a fixed amount of alcohol into the engine. In those days, results have always been very consistent and yield excellent power increase. But for the past few years, the results have been a mix bag. I could only put this down on the availability of the 2-dimensional AI controller. They are termed as an electronic progressive AI controller. Method of delivery is very similar to the mechanical rising-rate fuel pressure regulator. The flow is governed by the pump speed, the controller reads the manifold pressure via a MAP sensor, translates to a PWM drive signal to the delivery pump.

Lucky for some, the availability of stand-alone, piggyback type of engine controllers give user a high degree of control, changing fuel and ignition timing is a merely rapping a few keys on the laptop. In my view, I think this is the reason for the inconsistent result ? user?s interpretation of quite a complex ratio of methanol and fuel. Taking fuel out of the factory ECU to accommodate a methanol delivery system that has no reference to RPM, is a tall order. There are a few guys on this forum have managed it, I take my hat off to them.

My personal view on this relatively new concept requires a great deal of patience, dyno result means very little compared to logged data. Dyno-graphs always cause argument. I would really hope to see more logged graphs with AFR, Methanol flow rate, and EGT. If possibly the log should include a second to fourth gear run-up so we can spot the afr change due to Methanol. For those who has just embarked on the WAI, tune with 100% water - W50:M50 - 100% methanol and lastly 100% for ultimate power.

Need to clarify, get to experiment with water first and then add alcohol to until you are running 100% methanol. Lastly, you need to go a bit mad with crazy power, 100% water will be best.

Richard L"

EDIT:
another good read on this Injection Mixtures 101 - evolutionm.net

Where can I get methanol?

Last edited by turbojack; 08-26-2009 at 05:58 PM.
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post #2 of 21 (permalink) Old 08-22-2009, 01:47 AM
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Thanks for the info!! Great information

2004 Black Srt4 -
OLD setup - 11.6 @ 125mph with a 1.8 60' 5500' DA - S3 Stock longblock

Current setup:
E85, 56mm, Ported 1+2+, Built & Strapped....
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post #3 of 21 (permalink) Old 08-22-2009, 10:52 AM Thread Starter
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Methanol / Water chart

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post #4 of 21 (permalink) Old 08-24-2009, 05:15 PM Thread Starter
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Good threads on the RX7 club forum for users with nozzles.

AI NOZZLE/JET/ Delivery Sizing - RX7Club.com

Ai Tuning & Afr........ Important!! - RX7Club.com

Last edited by turbojack; 08-24-2009 at 05:23 PM.
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post #5 of 21 (permalink) Old 08-25-2009, 12:22 AM
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I'm still sketchy on how to mix the water/meth.

I normally pour a jug with half methanol, then add the other half with water. I heard this is really 30% meth?
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post #6 of 21 (permalink) Old 08-25-2009, 06:01 AM Thread Starter
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Technically methanol is different in a way that to get a true technically correct mix ratio you need to do it by weight. So a true 50/50 mix would need to be done by weight.

A good simple way is by volume........its not wrong. Meaning if you were to mix water and methanol in increments via testing and found that 40/60 worked best and this mix is represented as a mix by volume then your good, nothing wrong at all.

I guess it could be that when we talk about mixes we can ask people if there mix is by weight or volume so as to make sure everyone is on the same page.

IMO volume can be handled by everyone and its simple.
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post #7 of 21 (permalink) Old 08-25-2009, 01:09 PM
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Yeah, volume is easy and i'm lazy.

I mixed it a lil 50/50ish this morning. I was running straight meth last night but my new brew seems to keep 0kr as well. I was expecting atleast a blip of knock...but nada
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post #8 of 21 (permalink) Old 08-25-2009, 01:28 PM Thread Starter
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IMO, go get some 1 gal jugs of distilled water from the grocery store. Experiment with less volume of methanol. What you may find is that with a little methanol things work great and you save money on methanol, its safer to handle and safer to be driving around with.

Now realize though, if you have things setup are far as W/A kit tuning and nozzle size for methanol things could get out of sync in that with methanol you need large nozzles because you need a large volume, with water you need less volume and hence smaller nozzles.

Last thing, with knock, 0 (zero) knock as displayed on a gauge does not mean that best power is being made. You can flood the engine with coolant (water & methanol) and basically have little to no noticeable or displayed knock. But that does not mean best power. This makes more sense when looking at the Turbochargers & Knock doc and understanding it (not necessary to comprehend it 100%....almost everyone can get though it and grasp some important info).
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post #9 of 21 (permalink) Old 08-25-2009, 02:19 PM
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Yeah I was buying distilled water at the groccery store for it.

I'm not too concerned with making the most power right now as I don't like to push the absolute limits of my car, but I do see what you're saying. Although it would be pretty hard to be flooding with water/meth if AFRs are in the upper 11's, no? I try to go for a 12.0 tune
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post #10 of 21 (permalink) Old 08-25-2009, 03:45 PM Thread Starter
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Monitoring the A/F is not going to pickup the water being injected.............remember water is not a fuel, it is instead a coolant in this application and the A/F monitoring device is not going to pick up its use. You may pickup the effects of water in the combustion chamber using an EGT monitoring gauge.

The factory is using a very rich fuel mix in order to protect the engine, meaning its using extra fuel as a coolant. Tuners remove the extra fuel thats just being used as a coolant and has nothing to do with power being made. By removing the dumped fuel the power goes up.................thing is that you ideally want to put back in coolant by using a better coolant = water and some methanol. Without replacing the coolant you can risk damage (depending on the tune of course).

Water is better at cooling then fuel. Water and some methanol is better then pure water in most instances. Too much methanol without tuning for it and you are more or less doing the same thing the factory was doing with the existing fuel delivery = dumping fuel. With methanol being injected so heavily people get the octane value but IMO what good is race gas if you are pig rich with it, even race gas maps do not have a lot of race gas being injected by volume?

Also, too much water and you have too much coolant in the combustion chamber which does not make best power. The trick is to find the right ratio of volume and mix that makes the best power...............good tuners familiar with the effects of W/A injection make a good living knowing how to do this properly.

What I would do is get your fuel tuning done to where you are happy and safe. Then starting with water do some testing (pulls while looking at scan gauge or a device that logs). Then after maybe a tank full do your next tank cut with 10% methanol and do the same test. Keep cutting in 10% more each time till you see that adding methanol does not seem to be doing anything improvement wise. Now look at the tune again and see if there's any little tweaks that can improve this a little. You might want to see if you can add another couple of psi into the boost with the W/A working...........but again make sure that without the water and or methanol things still need to be safe.

To be clear with above that when tuning or re-tuning make sure the tune is not reliant on the W/A injection system if you do not have a failsafe.

IMO I think a proper tune and showing no leaner then 11.5 - 11.8 without W/A injection working is reasonable. This way if you do not have a failsafe and the W/A system has an issue while at WOT, theres much less of a risk in doing engine damage. Also, realize that a tune on one car at 11.8 may be OK and a tune on another car may not..........stock ring lands, high pressure, high heat stress, EGT and knock are serious things to consider under high loads, its not just a matter of A/F.

Last thing so there's no mistakes, for this particular post were talking about whats going on in the combustion chamber with water not about about removing heat from the air charge.
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post #11 of 21 (permalink) Old 08-25-2009, 06:54 PM
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Yeah, I tried the straight water thing on my M5 nozzle and it was still knocking like 6. That is with pulling no timing though and AFRs in the 11.8 range I think in a hot summer day. Obviously room for improvement.

But tuned for around 11.8-12.0 one time my meth stopped working...saw 4kr and 12.3. So not terribly bad.

Either way great info Jack
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post #12 of 21 (permalink) Old 08-25-2009, 07:34 PM Thread Starter
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Cool, just like with 100% methanol usage, 100% water usage is not going to work well without major tuning.

But with seeing both ends, you now have a better idea that there's ground in between that needs to be located.

I always tell first timers, to go with distilled water after fresh installs so as to be 100% safe, no mess in case of an install error because water will dry out oderless and it does not burn. I then tell uses to start mixing in the methanol at the second tank fill because too many users have different cars with different setups in different climates, using gas of varying octane................sometimes 50/50 is good for a user who does not want to play, but for basic tuning to see what works best no tuning skills are needed in using a msuring container and going out on the road and having some fun.

Also if you have the budget get a couple of nozzles and play with the volume. Also play with location. If you get some kind of nozzle bungs with blanking plugs you can experiment with moving the nozzle location around as well. You can also try splitting things up into using two smaller nozzles while using a Y connector. Materials and labor are not that bad and the experience makes the mod a lot more fun then a ported intake or bigger wheels and tires.

IMO people doing it this way understand things better, which is key to getting the results they want for the money spent.
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post #13 of 21 (permalink) Old 11-24-2009, 07:34 PM
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good thread, turbojack



must read for meth users, I hope this will shed a little light on the mystical W/M injection

JDP
JDP + BC = win, LMK people

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Originally Posted by CRZYCUBAN2 View Post
Theyre not old. Just seasoned.
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post #14 of 21 (permalink) Old 11-24-2009, 08:06 PM
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Look at you dude, droppin knowledge

Awesome read!


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Originally Posted by turbojonsrt4 View Post
gtfo srsly

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post #15 of 21 (permalink) Old 11-25-2009, 09:47 AM
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Much respect for posting such a great thread. Ive been adding water to my meth mix with great success the past week and a half.
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