Gents, I have an 85 Grand National and a 97 Z28... Was researching propane/water/alcohol injection for the GN and was wondering if that would be able to work at all on the Z28. Any insight/ past experience or advice would be appreciated... Mahalo

 

Is your Z28 supercharged or NA? Clearly, water works for a blower application. We have been experimenting with water/alcohol injection for NA cars at www.kennedysdynotune.com. It appears that if you have a car equipped with a knock sensor running on the edge of detonation (as 4th gen LT1's often do especially with marginal gas, and/or under high temp conditions) there may be some significant performance gains. The gains come primarily from decreased knock retard.

Is it worth trying? Depends what your goals are and exactly what setup you are running.

Rich Krause

 

Is there a site that delves a little more into this water injection? How bout a post? I'm all for learning something new.

 

What do you want to know?

Rich Krause

 

Well, I'm basically a basic mechanic. I know just about everything about a N/A LT1. But, when it comes to forced induction and nitrous, I'm a virgin. The very thought of water being injected into my engine makes me krindge. Now I can see this providing a cooling affect in the cylinders, but the engine would have to be low compression to prevent hydralock (I guess). My question, more or less, is what would be the application for water injection. How does it work and what does it do?

Kind of a broad question... I was hoping for a previous thread to clarify or atleast explain this. Mainly to save your fingers...

 

Water works in two primary ways. When injected as a fine mist into the intake, it vaporizes quickly. Because of the very high heat of vaporization of water, this has a tremendous colling effect. Heat of vapoization refers to the heat energy needed to convert water at 100 deg C to steam at 100 C. For water, this value is ~590cal/gm. For methanol, it's 290cal/cam. Are you getting the idea yet of why I use water/alcohol mixture and not straight water? BTW: 590cal/g is the highest of any commonly avialable solvent.

Anyway, the heat comes from somewhere. IOW, as the water vaporizes, it cools off the surrounding intake charge. That's why you have to inject it into the intake stream as a fine mist. It will have a much better cooling effect that way than if it's just piddled into the intake.

Once the water, which is now in the form of steam after mixing with the intake charge and especially having to pass through the hot area of the intake valve, gets into the combustion spave it thoroughly mixes with the air:fuel charge. After ignition begins, water effects them chemistry of the combustion process. It slows down initial combustion (equivalent to increasing fuel octane), and also helps combustion go to completion by forming some free radicals which act as oxidizers.

In a properly tuned engine, the produces more power. Especialy for boosted motors with their very high intake air temps. It allows more compression and more timing, just like intercooling.

Too much water will slow combustion to the point that power is lost. But hydrolock is not a problem on a properly setup system. The amounts of water are small. If it's injected as a fine mist, it quickly vaporizes. Is is only injected on a running motor, if the system is properly designed.

Water injected on NA motors is something we are experimenting on. There are gains, but we are trying to quantify the gains expected under specified conditions. The main value may be to allow use of pump premium or lower octane gas under difficult conditions (high load/low speed, high environmental temps, etc.).

The least expensive kit that offers accetable quality is the one made by my friend, Bob Kennedy. www.kennedysdynotune.com

Rich Krause

 

Wonderful post rich. I do appreciate it. As you know, I've been waiting for that all week....

 

more than a little and less than a puddle..... a piddle

 

heres my setup

http://community.webshots.com/album/77885215Iqhcdp


its going to be water only. its deliverd via 9th injector

 

on an historical note, water injection was used in WW2 in fighter airplanes....not sure if all that used it where supercharged or not (probably where)...it also demenished the engine's life spend greatly...I think you had to log it when you turned it on and after using a full tank of water, they had to change the engine...I would say it would be more of use for blown engine than na...

 

I meant to say that I use a water/alcohol mixture (actually 3:1) and not straight alcohol, due to the great cooling effect of water.

Water does not decrease engine life. What is the source for your statement? Water tends to keep internal engine parts clean, most notable whn seeing the lack of carbon deposits on the valves after a tear down. Of course, water is used only at WOT, or when under boost. That could cause confusion regarding engine life and water.

And yes, I do think "piddled" is a word!

Rich Krause

 

Rich - I hate to cut in, but could you give me some info on blower/nitrous setups?

Thanks,
Wes Buck

 

technically it is a word.

pid·dle

To use triflingly; squander: piddle away one's time.

v. intr.
To spend time aimlessly; diddle.

Informal. To urinate.

So, I think I got this setup.... You urinate in your intake, right? See I'm so smart.

 

rich..........have you guys done much research on propane injection? it would be interesting to see a side-by-side comparison of water/alky injection to propane.

it seems to be superior to water/alky injection in most ways, except that some people dont feel safe driving with a propane tank in their trunk.

 

What aspect would make propane better for this purpose? Yes, it would cool the intake, but:
Heat of vaporization of water ~790cal/g
Heat of vaporization of propane ~101cal/g

So it would seem water would be better as a coolant. As well, I'd guess propane has very low octane and might increase the chance of detonation.

As far as nitrous and a blower go, I posted this in a thread in the "Forced Induction" forum: It's a great combo, if it's done right. Bring a small nitrous shot in relatively low when you aren't getting much boost and turn it off when the boost comes up. Last year I was running 13-14lbs of boost and a 150hp nitrous shot. Brought the nitrous in at 3,200rpm and off at 5,400. This year I am running more boost, and will be using a smaller nitrous shot in the same way.

Cautions? Run it rich (I am running 11.5-12:1 with the N2O), run low compression (mine's 8.5:1) and strong forged pistons. Retard the timing with N2O (mine's at 27 degrees). Use race gas (100 octane unleaded, 104 this year for me).

Rich Krause