Good point. Let me think on this.

If running stock. The AFM will take a volume per portion of air into system and then cross reference this with temp to give us a proper density reading in witch returns a MAF. Now that this calculation has been dealt fuel in return is being dealt to cope with our stored MAF.

If MAF = 15 and F = 5 then C = 20

Now if W is added. It takes place of our A.

Then A = 12 and F = 5 and W = 3 then C = 20

But now that W has changed properties and as well has caused A to become more dens, turning our combusted MAF into something higher. Do we run lean or do we have another issue of C become grater then maximum combustion.

If MAF = 15 and W = 3 Then MAF = 16 and F = 5 Then C = 21
Else
MAF = 17 and W = 1 and F = 5 Then C = 23

With the ^ equation at thought of W changing its properties based on the equations posted by gingenhagen, basically splitting into H and O thus becoming part of the total MAF. Is this creating a false boost? In return running the system lean. Or will the total MAF escape before combustion resulting in a proper MAF = 15 reading?

 

The obvious is being overlooked. J-Rat is using so much alcohol that he has built a dual-fuel system. He is replacing gasoline with the higher octane alcohol rather than injecting a fluid (water) simply to suppress detonation. Water is a good detonation surpressant and I'm reasonably sure J-Rat can inject enough water to effectively suppress detonation. Will he make as much power as with the alcohol? No, since we are relying 100% on the gasoline for the energy rather than gasoline and alcohol. Alcohol has less energy per gallon than gasoline, but becuase it carries some of it's own oxygen you can use far more alcohol than gasoline so that you end up with more heat energy and therfore more power. All we want from the detonation suppressant is to slow the combustion process. Rotary engines by the nature of their smooth, but long combustion chamber are relatively resistant to preignition, but are still susceptible to detonation. Alcohol itself susceptible to preignition, but the rotary's combustion chamber offsets this defficiency.

Here is a good read on fuuels: http://www.turbofast.com.au/racefuel.html

 

I do, and have been doing it. I run 100% water injection. I had my pump fail, and ran 17psi without WI.

Now that my pump is fixed, I run 17psi with WI. the difference, I feel better that my intake charge is cooler...and yes I've logged the difference with Haltech, I don't care who says it doesn't cool the charge, only the chamber temperature.

great thread...got me thinking about alcohol mixture.

 

Allow me to clarify:

Pump gas in the Old Pueblo (Tucson) is 91 octane. Now, no matter what experiences any of us have had, I personally would NOT run 17 PSI on 91 octane.

 

is anyone out there running both water and alcohol/meth injection?
would this be beneficial at all?

- Aaron

 

Ah, iceblue, why are your posts so hard to read... Takes me like 3 reads before I get what you're trying to say, and even then I'm still not 100% sure, haha.

There is no reason water injection would take the place of fuel. You have the exact same air- fuel mixture, except that there is now water added to it. Ok, um... Say you have a sealed empty box (empty as in there's only air in it). Then somehow with some kind of one-way valve, you pour some fuel into this empty box. So we have an air-fuel mixture. Then you put in some water. Now you have air-fuel-water mixture. No fuel is being magically displaced and there's no reason to tune down your fuel. You've still got the same air to fuel ratio.

The air-fuel mixture is compressible. 10+5+5 = 20. Furthermore 20+5+5=20, so does 20+10+10, so does 100+100+100. However much air, fuel, and water you want, you can stick it all into your engine until the whole thing becomes a solid.

Why would you subtract A to comensate for W? Why why why?

Yup. Cooling the intake charge results in increased charge density. Intercoolers have that as their main purpose. http://www.aquamist.co.uk/info/images/tdrop.GIF

Water has an additional cooling effect upon entering the chamber which results in even greater volumetric efficiency (read more room for more air/fuel mixture!)

Again, water is not displacing any air. If it is, the amount would be so miniscule that equivalent to zero displacement.

The AFM can sense the temperature of the air ingested, and adjusts fuel accordingly. There are other assorted sensors which all contribute to calculate how much fuel is required at any given time t. If you don't like the systems in place, go tune the car yourself with a standalone.

The extra water results in a need for advancing timing. This is all part of tuning.

WHAT??

I don't understand why you persist in using these equations... Anyways, as a side note, MAF starts for Mass Air Flow, which is a technique to measure how much air is being ingested. So I don't quite get what you're trying to say when you have MAF all over the place. But I'm guessing you're trying to say the amount of air with increased charge density.

Also, I just noticed that your C is changing. I thought C was supposed to be your chamber volume (which would be constant)? If it's just the summation of air, fuel, and water then the total mixture may be pressurized at will, allowing it to fit in the constant volume of the chamber.

 

Yes, many people run 50/50 water/methanol.

 

Some more information, and links:

12) Why alcohol over water? This is the big controversy on the internet injection sites. While proponents of water can be found on various injection websites, it has been my own finding along with others, that injecting higher concentrations of alcohol as compared to water can produce more power. This is due to the fact alcohol burns and water steams. They both offer detonation control, but the higher octane afforded by alcohol, allows for far superior horsepower production. Top alcohol dragsters are examples. They run tremendous cylinder pressures on alcohol and if one looks at the intake manifold on an alchy burning racecar, it will look ‘iced down’ after a run. Also, because of the cooling properties of alcohol, these types of racecars are typically left running in order for engine temperatures can be raised. That shows how effective alcohol can be.



How does one tune a system? This is the question where starting out mild then going to wild pays the most benefits. Typically, for a few lbs. of boost over stock levels almost no changes are required. For higher power levels, recalibrating (reducing) the fueling and incorporating higher volumes of alcohol while adjusting timing will yield the best results. This is an individual thing. There is no one set of rules that will apply to all vehicles. There are too many variables.


http://wrxhackers.com/alchystuff/page1.html

http://home.att.net/~alkycontrol/page8.htm

DIY Alchy kit that will run approx 200 bucks max:

http://members.***.net/stevemonroe/AlcoholInjMod.html

 

No need to argue about top alcohol dragsters. Alcohol certainly has a higher limit. But, when operating in situations where both water and methanol work (dunno where but the limit is certainly above 600 HP), water is better. Why?

Consider that we desire a certain amount of boost. Then to make max power at that amount of boost, there is an optimal fuel/air ratio. The problem is at such high levels of compression, the combustion gets extremely hot, such that there is extremely high risk of knocking. So then there is a certain cooling factor we must achieve in order to eliminiate knocking at this boost level.

We can reach this level through water injection. Inject the water, and the intake charge gets cooled, the combustion chamber walls get cooled (eliminate hot spots) and thus knock is eliminated.

We can also reach this level through methanol injection. Methanol has the same effect, but isn't as effective, so we inject twice as much methanol by volume as we would water to match water's cooling properties. However, methanol is also a fuel, so we need to turn down our fuel injection so as to maintain the optimal power ratio. There's no extra power from methanol, because there's not enough air to utilize it. Want to increase the air to utilize the extra methanol you injected? Then go back to step one and repeat this thought process with a higher set boost in mind.

So what's the end result? Water injection and methanol injection do the exact same thing. There is no advantage to one or the other when you consider only the cooling factor. I suspect water has other effects which help control the flame front and increase reliability, but let's ignore those for now.

But now we have two systems which do the EXACT SAME THING. Except that water is free and methanol is very expensive. Then again, we must consider that if you're a dragster with extremely high levels of boost required, so high that water no longer works; then alcohol is your only option. But for every single street car there is, water is the better choice in my opinion.

 

because you have to! If you have a empty box with a volume of 50 that is the occupied air space. Now if we add water the air space MUST take a hit. The air must decline its MASS to obtain fuel/water. So if we add water to our system we take a hit in air and thus changes out AFR. Now if we inject another type of fuel we increase fuel and decrease air. Again changing the AFR. On a tuned system you could cut back the GAS to compensate the new fuel and obtain a proper AFR. With water as a non combustible material and doing nothing but cooling it must in physics laws change the AFR's.

Why do some of my equations have the W taking place of the F. Well to demonstrate the possibilities. It is not saying it will do this. In-fact it can only do this during a tunable system. It is a good example of using a fuel such as methanol.

Why do I have an equation of C = > 20. Well because if you were able to keep your A ratio perfect for the amount of fuel delivered on a predetermined EMS then the only way this is possible is to increase our Cv. So the equation is an example of what would happen and was a question at the same time of saying how do you deal with it.

It doesn’t matter if the A is compressible. You stated AF is compressible but that is false. F is not compressible; you can not compress a liquid. Now we can compress A but that is already accounted for in the EMS. So by adding density we are raising our volume/CFM that has entered the C. This indoutably changes the AFR.

Why did I keep using MAF? Because MAF is the measurement for the total amount of A volume obtained with its calculated density. A full reading. If we only used AF then we would not have out density measured. This would yield an improper equation for what I was trying to say.

 

I think gingenhagen's point is that the actual ratios (by volume) are more like
A = 100000, F=10

So if you add water:
A = 99995, F=10, W=5

and the difference in A is not even worth worrying about

 

Air mass is NOT declining. Your AFR ratio is NOT changing by injecting water. Say you have 10 parts air and 1 part fuel. The air fuel ratio is then 10:1. Then we add 10 parts water. What's the AFR now? (10 parts air) / (1 part fuel) = ratio of 10:1!!! You obviously do not understand physics if you keep on saying things that are blatantly wrong. Garr, I'm not going to waste any more of my time trying to explain things to you.

 

Ummm....

I am not arguing, that was just some random information posted on a website (which I linked), that I found interesting. If you want to debate that point, I may suggest that the author of that website?

 

Hehe I understand the number alot betor then words ;-) I agree with you YellowT2 and say at this point and his point when going about it as you did is valid and acuret.

My point was to show how the propertys complimented each other as a way of showing what has to happen, and people to easaly see where alcohol and water differ. As well to show how the barrier of to much water is easaly found.

 

J-Rat: Oh, sorry. I'm in a contentious mood today.

 

Myth: water injection displaces air

Facts:
To those who are worried about injeciton displacing air, consider that approximately 99.875% of air is empty space. That empty space = plenty of room for water molecules to fit in. So actually the amount of air being displaced through water injection isn't "low" but is actually "zero."

 

You are missing MASS totaly. Yes your above AFR is correct 10:1. That is a 100% full C, all parts are used,all volume is obtaind. If you add water there is no ware for it to go, nless you lose ither A of F. So now if you add water as I have demonstrated in equashions your A will decline to something like 8:1:2 where 2 = W. This AFR is changable via tuneable EMS but not factory setup.

 

The only empty space is a black hole. Air is oxogyn, hydrogyn, carbon deoxcide, and monoxcide and all other sorts of ploluted shizzle.

 

I am going to summarize here, and then you all can continue to discuss..

From doing hours of research, it appears that there are 3 different schools of thought. These comprise of water, water/Meth or alchohol, and straight alcohol or meth. I have even found people injecting Nitromethane! I bet thats fun!

I am going to maintain my point that because I am able to inject more alcohol and remove fuel, I am more able to make use of the cooling properties of alcohol, therefore I get a signifigant amount of cooling, while increasing the octane of the total mix. These are facts that I can prove.

Can I prove what the advantages over water are? Nope, I haven't ran water, so I have no quantitative data to compare too. Add that to the fact that I am not a chemist (I am an electrician), and I can't tell you what kit is better, I can only tell you what I prefer.

Either way, the info is there, and one thing that EACH AND EVERY SYSTEM CAN DO IS THIS:

It can allow you to run signifigantly higher boost pressures, and more aggressive timing curves, or it can just provide a margin of safety above and beyond. And this all can be done on PUMP GAS. Thus negating the need to spend money on race gas, which is now at around 5-7 dollars. In addition, each system can cool the intake charge (a process known as Chemical Intercooling).

So there it is. Enjoy the information provided!

Rat

 

*Air is oxygen, hydrogen, carbon dioxide / monoxide, nitrogen... "and all sorts of polluted shizzle" *

 

HMMM!!! This just gave me a thought. Not entirely pertinent to the discussion, but also not entirely off topic either...

Has anyone ever used a closed-system water-to-air intercooler, and filled it with alcohol or methanol instead of water?

 

water has better cooling properties than alcohol or methanol (about twice as good). This is one place where using extra amounts of alcohol or methanol can't compensate.

 

This isn't exactly correct. Yes, you are right, that the air has space within it, but regardless, the air isn't going to compress itself by just allowing the water to take it's space. We're not under compression yet, so the air is just going to move away, meaning it will displace. Now, the curious question, how much will it displace? Under my setup, I'm roughly around 85:1. Which, as you can guess isn't a whole lot.

 

Party Foul. Unless your name is Robert Harris, you're plagiarizing. Please give the guy credit where credit is due.

If you guys are looking for some actual scientific research work, here's my link collection on the subject (with some water vs. alcohol/water research):

http://not2fast.wryday.com/thermo/wa..._chemistry.txt
http://www.andern.org/alexander/wi/naca_H2O.pdf

http://www.amazon.com/exec/obidos/tg...books&n=507846
http://www.sae.org/servlets/productD...PROD_CD=460192
http://www.sae.org/servlets/productD...PROD_CD=690018
http://www.amazon.com/exec/obidos/tg...books&n=507846

Ricardo's book being one of the definitive research works.

 

my bad, sorry about that.