mapmaker50

I hope so too.


Neither is fuel in the absence of oxygen - but it will eventually help to light up a dark street at night from the tailpipe though.

turboICE

A quick run using a four gas analyzer will show that the levels of CO and lack of oxygen exiting the exhaust that within the cylinder any fuel being dumped in excess of 12.0:1 definitely is not combustible in those conditions. Most performance combustion chamber designs are efficient enough that any gasoline being used in excess of 12.5:1 even will not combust within a cylinder once all the oxygen has been used. Besides the poor cooling qualities of gasoline, Glassman has proven that excess hydrocarbons inhibit the complete combustion of gasoline and that water in fact improves the proper oxidation of CO to CO2 and this last stage of combustion is where a major source of energy is released during the combustion process.

* Source: Combustion, Third Edition, Glassman, p. 76

This is why when no changes are made to boost and the existing AFR is richer than 12.5:1 richer settings will result in less power and leaner settings will result in more power provided knock is suppressed, which is where injecting water and water mixes comes in - not to replace combustible fuel but to replace fuel that will not have sufficient oxygen to combust. Without oxygen gasoline does not combust either.

mapmaker50

So Fuel Dumping, or sometimes termed as " Advanced Fuel Management" is a band aid" to poor tuning?

shiv@vishnu

iTrader: (20)

You're assuming an homegenous air/fuel charge. This is rarely the case where there are packets of air and packets of fuel swirling around independantly in the cylinder during compression. Need to run more fuel than what is "theoretically ideal" to ensure complete and stable burn. Also need to control the rate of the burn with extra fuel in order to surpress detonation. Dyno doesn't lie. Neither do good books. But they can surely leave out a few facts.

Shiv

mapmaker50

Shiv,

What is your recommended a/f ratio to ensure all charge air is burnt then - lets say WRX and EVO

turboICE

The theorectical chemical combustion ideal is stoich, inefficiencies in the air fuel mixture have been taken into account in the examples of 12:1 and 12.5:1 which are plenty rich to utilize all the existing oxygen. The rich ratios of 12:1 - 13:1 have proven time and again to be the optimum power AFRs using multiple measurement methods exactly because of mixture and chamber inefficiencies.

I believe your site has shown that dynos can and do lie. Even most wide band lambda readers lie since they are not calibrated per the sensor manufacturer's instructions as frequently as they should be. However a calibrated four gas analyzer doesn't lie, I have never seen a combustion chamber that was so inefficient that all oxygen was not completely used up by and usually well before 12.0:1 AFR.

Besides Glassman's own work there are many others that also show quite well that present water before combustion begins is excellent at improving the burn profile of hydrocarbons and at suppressing the occurrence of knock.

http://naca.larc.nasa.gov/reports/1945/naca-report-812/

And Sir Ricardo's output measurements:



There is not an aspect of combustion that Glassman has not covered. Now, some other pop automotive literature authors that have never had any of their writings peer reviewed or even provided an objective comment to be reviewed may have omitted some facts.

I don't disagree at all that excess fuel suppresses knock and makes for a good forced induction tune, but there is ample peer reviewed and widely tested evidence that water is preferable for this purpose. There is no suggestion to replace gasoline that would combust with water that wouldn't.

Lastly this technology is not for everyone - it adds complexity, requires monitoring and maintenance, if the WI system breaks the engine likely will (lacking an automated response like a boost cut) - if the fuel system breaks the car stops running (of course unless there is a partially blocked injector...). This is not set it and forget it - for those that want simplicity then fuel dumping is the much better approach for two reasons it will keep an engine in safe tune and doesn't require any more attention than normal fill her up and turn the key.

mapmaker50

TurboICE - Thanks for the posting some real information about combustion dynamics, makes Shiv's claims of dumping fuel is superior than water injection futile and limp.

I don't know where Shiv's dyno results were based on - virtually all dynos read differently from different tuning companies- someone is lying somewhere. Read Shiv's write-up on how one can fabricate and falsify results dyno figures on his site.


Shiv often refers and quote excerpts from Corky Bell's book, I suppose that was what he meant by a "good book". Somehow, he has been sending Corky's "anti-water injection" slogan such as "band-aid" etc. to the masses.


Shiv, I would still like to know the answer on my last post :

shiv@vishnu

iTrader: (20)

If you actually read my post, I never said that water injection doesn't work. It just hasn't worked awell in the Subaru applications I've used it in. I even said, and explained why, I thought it may be of some benefit in EVO applications. Please don't misrepresent me. If you like WI, use it. Just visit a dyno to make sure that you are making power before with it than without it.

Shiv

mapmaker50

Xede can run the Aquamist's 2c or 2d directly on one of the spare channels. There are two spare channels, one for boost control and the other one for intercooler spray.

User can reconfigure either channel for Aquamist, map against Load and RPM. I believe TurboICE has the details how to do it and how to avoid potential problem - worth pm him before proceeding.

This discussion yielded some positive comments from either party and hope Works Water Injection development for the EVO8 will be the start of a new alternative for Fuel Dumping.

I look forward to hear any results from HiVoltEVO8 if he is going that direction.

ez76

iTrader: (5)

I don't know jack **** about jack **** but it seems that relying on water injection to make power is more or less akin to relying on nitrous or any other supplement that is likely to go empty much sooner than your fuel tank - even with a switchable set of maps, seems like you'd need instrumentation and vigilance to ensure you cut over to your "waterless" map in time, no?

The science and analysis is very interesting but is water injection really necessary to extract maximum power or is it just one approach of many? Definitely seems like it has practicality trade-offs vs. running extra or higher octane fuel.

turboICE

ez - you grasped more than most do.

WI doesn't make power - it is a tool that can permit more powerful tuning. Nothing like nitrous though since nitrous is an oxidizer that allows more fuel to be burned when it is added. But also it doesn't run out as fast - a gallon resevoir of a water mixture can last 20 gallons of fuel and more on the road once the novelty has warn off. The track does necessitate a larger resevoir. Absolutely you want instrumentation and vigilence and an ability to cut to a tune that is safe without water - too many skip that step when they try WI.

It is an alternative. Though a personal advocate of WI when implemented properly - higher octane fuel is a better solution if it is feasible for the user to run it. Though some tunes are still agressive enough not to achieve optimum power AFR even on 110. But with a higher octane fuel a WI user should inject much less water since there is going to be a lot less excess fuel dumped. Its about knock suppression - if you are at optimum power AFR and MBT without knock (which is nowhere richer than 12:1) because you have sufficient octane don't even look at water injection. Some describe the effect of water injection as increasing the effective octane in the cylinder - direct octane improvement is preferable in my opinion but for some that is not a good alternative.

mapmaker50

ez76,

For DIRECT in-cylinder cooling, there are only two ways:

Water injection or Dumping fuel

I am sure someone will come up with the third way soon. It was the very reason that fueled the long discussion above.

DRWN KIX

iTrader: (2)

The problem that is twisting me is that my car is a daily commuter and I want more power. Al & Shiv don't really like tuning with 91 octane. If I could buy 100 octane and mix at the pump to 94 it would be a big improvement. I could remap and get a significant power increase without decreasing gas mileage. (at a cost of about $10 per tank) Distilled water I can get anywhere. What ratio is appropriate? I would guess that a small amount of water would go a long way and be very economical to run. If the quantity carried matched the gas tank capacity it would simple to check every time you filled up.

turboICE

Generally, while water injection is engaged (only during periods of boost >6-8 psi) the ratio would be 10-15% water (water/methanol mixture) to fuel. At first some will run through a gallon in half a tank. However, once the novelty of the new tune wears off a gallon resevoir should last two - three tanks of gas on a daily commuter. A water level sensor is always highly desirable and there really is no reason not to have one when it is your source of knock suppression.

Ryanmcd3

Also the xede has 2 maps, what if when the water runs low it changes to the other map that does not use water injection?