bch5428

ive been researching water meth injection for a few weeks now, i thought i would post here to see what some people with previous experience have to say.

just got my car tuned by me - see sig - and im looking for somewhat of a buffer for disaster. ive read about how W/M richens up the afr a lil bit, and im worried it would affect the tune to much. im not looking to rely on W/M in my tune, id like to supplement my current tune with it. i was curious if straight water injection would help significantly enough in regards to IATs and possibly EGTs. My EGTs are relatively high but steady at 1550 after a 3rd - 4th gear pull. id like to avoid redyno tuning my car, which i why i was considering the staight water injection. Is that pointless and defeats the purpose of W/M injection itself? i was gunna go for a base injection kit and spray after 12psi. any advice would be much appreciated.

Also, does anyone have any recommendations for washer fluid brands?

incase its needed the stats are:
d16a6
2.5 bar map sensor
hf/mani evo3 big16g @ ~19psi
450 dsm injectors
sft4 front mount
stock top end - wiesco/tt rods bottom end
IATs = ~130 on dyno
~9* timing at ~19psi
~11.7 afr through out boost
tuned via turboedit

quicksilver1689

water injetion i usually used to push the limits of " pump gas octane" fuel. It will almost simulate race gas in tuning, you can run more timing and more boost. I'm not sure how high, but the effective octane of the pump combined with the meth/water injection goes up pretty high ive heard around 110 octane before but i would think it would be somewhere between 100 and 110. It acts like a buffer because the methanol helps stabilize your combustion, the water soaks up heat, your motor stays really clean inside, less carbon deposits. Yes if you use it youll have to retune to it to see some gains, you might gain or loose power slightly, water will bring down the iat's while the whole theory will throw your afr's off a little bit to the rich side, so if your running 11.5 afr it might go to like a 11.2 or 11.0~. Hard to say with all the variables. Do some research on the web theres alot of info about it! Good luck

bch5428

yeah ive been plugging away at the research deal, i was hoping some people with experience could chime in but it seems ill have to do that first hand experience thing.

for the most part i understand the whole increase the octane and the advancing of the ignition timing works. from what ive learned so far, most people can back off their fuel tables because the meth picks up the difference! heaven forbid you run your injection tank dry

ive found it difficult to dig up information regarding straight water injection, which lead me to post here, but it also lead me to believe im wasting my time. worst case scenario i get to learn, aww shucks.

does anyone have any suggestions regarding nozzle sizes? i was going to go with 3gph nozzle, specifically looking into a universal devils-own kit. seen a few locally at the track and spoke with their owners; i have yet to see a non progressive kit being used, are they that much more efficient? i understand the injection curve adjustabilty and such, but it seems a little over the top for my set up. like i said in my previous post, im not doing this for a power-adder, but more for a safety buffer.

quicksilver1689

The latent heat values of different liquids are shown here:

Gasoline 350 kJ/kg
Water 2256 kJ/kg
Ethanol 904 kJ/kg
Methanol 1109 kJ/kg

sohc_turd

i used to run the Devil's Own Progressive kit on my vitara build. I had it tuned to 320whp at 17-19psi, 5gph nozzle, 50/50 mix.

I did a ton of reading and concluded that a 50/50 mix was best for street use. I used 50% denatured alcohol and 50% distilled water. And it just so happens that that mixture will maintain a fairly close gasoline stoich a/f ratio. It'll actually be off by -.1 a/f. And just for illustration purposes, 100% will richen a/f, while 100% meth will lean out a/f. As you can imagine there are a hundred ways to fudge the mixture and target a/fs to get the car to run how you like it to run.

As for target a/fs, i usually shoot for 11.8-12:1, and usually go up to 5* more ignition in target boost areas. ***ignition values are for my car only, you will have to dyno tune your car to see how much ignition it responds to***


and also, it can make your life eaiser if you use a wideband that can display lambda.

bch5428

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sohc_turd &raquo;</TD></TR><TR><TD CLASS="quote">i used to run the Devil's Own Progressive kit on my vitara build. I had it tuned to 320whp at 17-19psi, 5gph nozzle, 50/50 mix.

I did a ton of reading and concluded that a 50/50 mix was best for street use. I used 50% denatured alcohol and 50% distilled water. And it just so happens that that mixture will maintain a fairly close gasoline stoich a/f ratio. It'll actually be off by -.1 a/f. And just for illustration purposes, 100% will richen a/f, while 100% meth will lean out a/f. As you can imagine there are a hundred ways to fudge the mixture and target a/fs to get the car to run how you like it to run.

As for target a/fs, i usually shoot for 11.8-12:1, and usually go up to 5* more ignition in target boost areas. ***ignition values are for my car only, you will have to dyno tune your car to see how much ignition it responds to***


and also, it can make your life eaiser if you use a wideband that can display lambda.
</TD></TR></TABLE>

nice. youre saying running straight h20 would richen the mixture and the opposite for meth? im really beginning to regret tuning my car before getting into this water/meth thing.

i woulda guessed you could advance timing more than .5*. how did you have your progressive tune set up, was it worth the extra $?

sohc_turd

Max torque is produced at 12.5-13 a/f ratios, anything richer is mostly used for thermal mangement. Once h20 is introduced, you can safely run leaner fuel mixtures because h20 has a higher latency of evaporation, and possibly slows the burn???

I'm not 100% sure but i'm positive that h20 slows the burn-upping the knock limit.

So to answer your question, h20 will richen the a/fs.

as for methanol, its got a different stoich than gasoline. If i remember correctly, it takes approx double the meth to gasoline. Maybe someone else can elaborate on that.

Sorry i'm on my way out the door... i hope that helps.

quicksilver1689

methanol slows down the burn makes it more stable and helps resist unwanted combustion at the wrong time just like higher octane fuel, h20 absorbs the heat.

quicksilver1689

I Do Not take credit for this info.
I found it on enginerunup.com!


The main benefits of water injection are:

1. Will significantly help to prevent detonation.

2. Will raise the octane of the gas you are using.

3. By reducing detonation, this will allow you to increase boost or run lower octane.

4. Lowers air intake temperatures which keeps the engine cooler from the inside out.

5. Will literally steam clean the carbon deposits from within the engine.

What is Water Injection:

Water injection systems are predominantly useful in forced induction (turbocharged or supercharged), internal combustion engines. Only in extreme cases such as very high compression ratios, very low octane fuel or too much ignition advance can it benefit a normally aspirated engine. The system has been around for a long time since it was already used in some World War II aircraft engines, which allowed them to produce more power and therefore fly at higher altitudes.

A water injection system works similarly to a fuel injection system only it injects water instead of fuel. Water injection is not to be confused with water spraying on the intercooler's surface, water spraying is much less efficient and far less sophisticated.
A turbocharger essentially compresses the air going into the engine in order to force more air than would be possible with the atmospheric pressure. More air into the engine means automatically more fuel has to be injected in order to maintain the appropriate stoechiometric value of the air/fuel ratio (around 14:1). More air and fuel into the engine leads to more power. However by compressing the inlet air the turbocharger also heats it. Higher air temperatures lead to thinner air and therefore an altered stoechiometric ratio which can lead to a lean mixture and detonation. Detonation, an effect also known as engine knock or pinging, occurs when the air/fuel mixture ignites prematurely or burns incorrectly. In normal engine operation the flame front travels from the spark plug across the cylinder in a predefined pattern. Peak chamber pressure occurs at around 12 degrees after TDC and the piston is pushed down the bore.

In some cases and for reasons such as a poor mixture, too high engine or inlet temperatures, too low octane fuels, too much ignition advance, too much turbo boost, etc., the primary flame front initiated by the spark plug may be followed by a second flame front. The chamber pressure then rises too rapidly for piston movement to relieve it. The pressure and temperature become so great that all the mixture in the chamber explodes in an uncontrolled manner. If the force of that explosion is severe some of the engine's moving parts (pistons, rods, valves, crank) will be destroyed.
Detonation, in any engine, should always be avoided by either lowering inlet temperatures, using higher octane fuel, retarding ignition (hence lowering engine output), lowering engine blow-by (a situation in which high crankcase pressure sends oil fumes back inside the combustion chamber), running the engine a little richer than at the stoechiometric ratio, lowering the compression ratio and/or boost pressure, ... .
Water injection is used to lower in-cylinder temperatures and burn the air/fuel mixture more efficiently thus helping avoid detonation.

In high pressure turbocharged engines the air/fuel mixture that enters the cylinders can, in some cases, explode prematurely (before the spark plug ignites) due to the extreme engine environment conditions. This situation is extremely destructive and results in severe engine damage (piston piercing). To avoid damaging the engine by detonation or pre-ignition phenomena, water is injected, along with fuel, in the combustion chambers in order to provide a water/air/fuel mixture which not only burns more efficiently and avoids detonation or pre-ignition but also provides additional inlet air cooling and, hence, denser air. The sole functions of water injection is avoiding detonation by lowering air charge/cylinder temperatures along with increasing the effective octain of the air/fuel charge, so the ECU can advance timing and take advantage of the increased boost.

There are mainly three variations of water injection systems. They are dependent of the location of the water injectors. The first technique consists of injecting water at the entrance of the intake manifold. The second injects water at the exit pipe of the intercooler. The third technique injects water at the entry of the intercooler and is only used in competition vehicles. In this latter variation most of the in-cylinder detonation prevention is done by injecting additional fuel which is then used as coolant (i.e. is not burned) and runs the engine above the stoechiometric ratio (i.e. rich).


Modified by quicksilver1689 at 5:19 PM 8/20/2007

sohc_turd

where did you plagerize that from? lol...