Hey guys i'm not a Diesel owner but I would really like to know why in the world would you mix water/meth with your fuel...
And what's it supposed to do?
Cuz I have no clue

 

It reduces detonation, I've heard they used to do it to gas motors in the 70s and 80s so you could run the old high compression motors on the decreased octane lead free gas. I have only seen one in person and it was on a 68 Z28 and was a owner said it was kit from holley the guy put it on in the late 70s because the car wouldn't run on pump gas that was avalible from holley, just poor in some washer fluid and go.
-Johnboy

 

Wow... thats a new one for me sounds like if some thing were to mess up its a good way to crack a valve or worse..
Oh by the way is that a tricked out AK? or some model of a G3

 

It a SIG 556, yeah pretty much just a tricked out AK but made here in the US and chambred in .223 and takes standard AR/M16 mags
-Johnboy

 

Sweet cant say i've ever seen one..

 

I am really amazed that its not used more than it is. The Buick GN guys and the Supercoupe guys use it with great success. Almost a "must have" when pushing a lot of boost. Some of the HP the GN guys are pushing out of those 3.8's are unbelieveable. Couldnt do it without water/alchy injection. The alchy does add power, but the primary power seems to come from lots of fuel and lots of boost!

The simple quick answer is that it cools the mixture down--drastically. I dont have the figures now, but when boost goes so does the mixture temp. There are charts to show the relationship of temp to PSI. I have watched water/alchy injection for many years. WWII fighters used on their supercharged engines, the most famous is the P51 mustang. P38's were also supercharged and used it. First time I saw it was on an olds "starfire" (it think) in the very early 60's, from the factory.

There is a lot of misinformation about water injection, such as the one about "cracked valves" or "washing" the oil off the cylinder walls. You "aint" supposed to turn the water hose on it , just enough to suppress preignition. It is actually going in the cylinder as a vapor. It is moved on through as part of the combustion process and is burned.

Just water alone allows higher compression motors to advance timing back to good power levels with low octane fuel. Water alone supposedly cost about 5% Hp. However that is gained back by bumping the timing back up. A mix of water/alchy, about 50/50 alone is supposed to add ~ 5% then you still crank more timing in for more gain.

With fuel injection cars now, the mix has to be "injected" into the cylinder via a pump system. Carbs also required a pump, but not as much psi. In fact, I have an old Edelbrock injection system for a carb, still in the box new-----make a race horse deal on it Best laid plans-----.

Too much to cover here, surf some of the Supercoupe sites and the GN sites. A source is Snow Performance.

One more thing-----I am not an expert, but have seen a lot of info on other sites. You should arrive at your own facts. This is just kinda a FYI.

 

The water comes out of the injectors as droplets and quickly evaporate. Water and alky can absorb a helluva lot of heat. It also does some cool stuff during compression and just prior to combustion. I found a college research paper on the effects of water injection and it had some really in-depth information in it. Unfortunately, I didn't try to keep it.

 

Years ago when I first got interested, I read an article by an engineer----who knows, he could have been the paper boy! The gist of it was that at a no load cruise, a car can get by with very little octane. He even said that lower than 87 would work. That was in the day of 11to 1 and maybe more. As soon as you "load" the engine such as kicking it in the ---, the octane requirements go way up, but only for the duration of the load. Thats when water/alchy comes in. You dont pump it in all the time, only when needed and then only as much as needed. Best of all, just to keep something that can be driven on the street with high compression, plain water can be used and keep your timing up. Last I checked, you could still get water free!

I dont know just how diesels respond, but it would accomplish the same I'm sure. Heat becomes the enemy in everything thats boosted. I would build an engine (most are for hobbie any way and not a whole lot of driving) thats right on the upper limits of street compression and if you miss a little, dont tear it down and double gaskets etc, just water inject it. Havnt looked in a coupla months, but I thing good systems cost ~ $350. Check out Snow Performance, SMC (nice lookning systems also), at one time, Aquamist made a system, dont know about them now.

Do I sound sold on it? Right now, the hottest thing I have other than a 351 bronco is a Snapper rider mower-----dont think it has very high compression

 

Compressing air as you would with a supercharger/turbocharger requires "work".

That "work" generates a lot of heat.

The compressed air leaving the super/turbocharger, absorbs that heat and this means the intake charge is significantly hotter than the ambient temperature outside the vehicle.

In high boost applications it's not uncommon to see intake charge temperatures approaching and passing 300 degrees. This is why many high performance cars (or poorly designed turbo systems on medicre cars) have an intercooler of some kind - air to air or coolant to air - trying to reduce intake temperatures to something reasonable.

The hotter the intake charge, the more volume it will have. Boil a pot of water to see how this works for yourself - the pot overflows as the water takes up more space than the pot provides.

The point of all this?

The cooler you can get the intake charge to be, the more boost you can apply into the engine, which creates more power.

Injecting alcohol, water, methanol or a flammable compressed gas like NO2 (nitrous oxide) absorbs tremendous heat, reducing the intake charge temperature.

With the exception of water, the others I listed also burn - producing power.

Only inject clean substances - tap water really isn't a good idea. Use distilled water as it has no pollutants, minerals, flouride or chlorine.

The other really neat side effect of injecting liquids that "flash" into steam vapor, is that process will also keep your engine crystal clean - clean valves allow for more flow - clean rings seal better, clean pistons promote faster burns and less hot-spots thus less detonation, clean plugs spark better and more consistently - important in a boosted engine.

This all applies to diesels as well, and probably moreso because the compression ratios are much higher - typically 18:1 or something along those lines. Lowering the intake charge temperature means you can pack more of said intake charge into the chambers - just like with a gas engine.

More intake charge, more power, more joy.

Years ago I built a mopar-based 451cid stroker - a "B" 400 cid block with a 440 crank, buick rods, and wiseco pistons. Static C/R in the 8:1 range - lower than is typical, but the plan was to turbocharger it - which I did with a pair of 'em.

Without an intercooler or water/alky injection, I could run about 18psi or thereabouts. Certainly, that was a fun amount of boost and that was fine... but with a powerstroke intercooler (i.e. HUGE) and carefully tuned water/alky injection system, I almost doubled the amount of boost I could feed it - at 4500 RPM as a "decided" redline.

451cid with 30 psi of boost is certainly in "scary" territory. Because the RPMs were seriously low, the engine held together.

What pops heads is cylinder pressure.
What breaks rods / piston tops / crankshafts / main caps is RPM - remember that the force the rotating parts sees "squares" with every 1000 RPM - often past the strength of the material if it's "common" like mild steel, aluminum, and cast iron.

 

FYI.......
I still have my Spearco water vapor injector unit!!!!!!

 

Labonte racing builds nice kits - best of all i have seen that are affordable, sort'of. Aquamist is definately the king but expensive.

dunno if it still holds true, but i was told many years ago, that 1deg of advance in cruise was equivalent to 1mpg increase in mileage.

as water/alky mix helps supress detonation, one could run more lead (i am up to +6deg in an '95 EFI Ford BB van) to improve mileage and then when under load the injection kicks in and keeps your motor from detonating. fwiw i was running primative h2o injection back in '73 on benz's.

also, i do have some interesting info on how to do a system on the cheap. drop me a line and i will try to find all the links and make some comments and get them posted.

neil