Does anyone know why WI works?

[TurboSy]

I'm looking for a detailed explanation of how WI works. In the past few years I've used both water and alcohol, but still don't totally understand how it reduces egts, well actually I've seen first hand with a wideband why alcohol reduces egts, but how does water work? I hear people all the time say it cools the intake charge, which is obvious, but there must be more to it.

 

[bruce]

Google for NACA, and then for in-cylinder cooling.
Then get a copy of Dir Harry Ricardo's High Speed Engine Design.
Then search the DIY-EFI site for posts by Bob Harris.
Doing the above will get you the original reports from the people that did the actual research, not reguratated, BS, and hype.

Then reread it all 2-3 times.
Fascinating stuff!!!!!!!.............

Then if your really really serious go to some tractor pulls and get into the pits and see what current executions of WI look like.

 

[TurboSy]

Thanks Bruce

 

[TurboSy]

Ok Bruce after reading a bit I have a question. Currently I'm running an afr of 12.0-1 without WI, I guess I'm fuel dumping to off set detonation. Is the idea to replace fuel with water as a means to control detonation? Is it theoretically possible to run an afr of 14.7-1 at wot if you could inject enough water?

 

[bruce]

Originally posted by TurboSy
Ok Bruce after reading a bit I have a question. Currently I'm running an afr of 12.0-1 without WI, I guess I'm fuel dumping to off set detonation. Is the idea to replace fuel with water as a means to control detonation? Is it theoretically possible to run an afr of 14.7-1 at wot if you could inject enough water?

Your asking good guestions!.
Trouble is there isn't short answers, but in summary.

Adding fuel is to cool the chamber.
You can do the same thing with water.
When introducing water you can do it by atomization, or vaporization. That's why people have better results with differing brews of alky/water.

In theory?, Yes.
But, in actual application there is more to it then that. Reading the Harris notes will explain the chemistry end of things better.

A couple freebies:
On a pulling tractor they use as much as a gal of water in 20 secs.
When test firing the WI system on the tractor, it makes a cloud of water vapor that takes 30secs or so to disapate. It's seriously atomized.
The discharge tube off of the turbo turns the paint to charcoal, but starting at the first WI port the paint is perfect. And I do mean charcoal, and I do mean perfect.

 

[TurboSy]

Here's a few post by Mr. Harris, for anyone that's interested :

http://www.diy-efi.org/efi-cgi/list...2001=1&s_2002=1&list_gmecm=on&list_diy_efi=on

and the naca search page:

http://naca.larc.nasa.gov/

 

[turboost]

If you can inject water into a flame at the right amount of "mist" (can't think of the right word) the flame will burn hotter and cleaner due to the increased oxygen and hydrogen. The problem is getting the right amount so that you don't smother the flame but yet have a stronger burning flame. Water also has a hgh specific gravity so it can remove more heat than alcohol or gasoline can.

 

[pat83t]

also check here. http://www.aquamist.co.uk/ they have some good info.

 

[Chyke]

The specific gravity of water is not(for this discussion anyway) the property of H2O that allows it to disipate heat. If this were the case gear oil would dissipate heat like a mother.

Oh and the word is "Atomization" or the act of mixing a fluid with a gas at a well defined molecular state. Allows better dispersion and equlibrium in the vaporization of the substance.

Ph.D in chem....

 

[TurboTR]

>the flame will burn hotter and cleaner due to the increased oxygen and hydrogen.

So it sounds like you're saying the hydrogen that's already burned, ie water, seperates in the combustion chamber and provides fuel (hydrogen) and the oxygen to burn again? That's an interesting theory.

TurboTR