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Old 05-05-2005, 10:18 PM   #1
gf8rallywagon
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Default water injection ?'s

Ok, so i've been reading on here a little bit of the tuning threads, and i keep seeing things about water injection...

My question is, what the hell are we talking about? please forgive my ignorance but if it is exactly as it sounds then we are injecting water directly into the cylinders (or in combination with the fuel mixture)... From my learning (which i admit is limited) water doesnt burn. And an unburnt liquid is not compressable (this is the basis of hydrolock, correct). Now are we talking such limited amounts of water, as in a fine mist, that it doesn't cause any possible harm? if so i can see the main benifit, cooler cylinder temps... is this correct? are there any side benifits to this? also is this type of setup meant for only turbo cars or could heavily modded n/a scoobies also benifit from this? and can anyone explain this:
, , , ,Load,Knock, , , , Mod, Mod , , Mod,
RPM, MAP ,MAF,TPS,Site,Count, AFR, Ign#1, Inj#1, Ign, Fuel,Boost, MAF, WB
, psia, V , % , , , , deg , duty , deg, % ,(CL) , V, O2
5200,+12.9,4.2,100, 80, 00, W/B ,+24.5, 46.2,+24.9, -6.0,305.00,3.2, 10.86
5455,+14.9,4.2,101, 90, 00, W/B ,+26.2, 48.0,+25.2, -6.0,310.00,3.3, 11.80
5698,+16.1,4.2,100, 80, 00, W/B ,+26.9, 47.0,+26.8, -6.0,320.00,3.3, 12.59
5889,+16.5,4.3,100, 80, 00, W/B ,+28.3, 48.8,+28.2, -6.0,325.00,3.3, 12.74
6277,+15.5,4.3, 99, 80, 00, W/B ,+28.7, 50.9,+28.6, -6.0,330.00,3.3, 12.74
6510,+14.7,4.3, 98, 70, 00, W/B ,+30.9, 55.4,+30.0, -5.0,330.00,3.4, 12.59
6587,+14.1,4.4, 97, 70, 00, W/B ,+31.2, 56.0,+30.0, -5.0,335.00,3.4, 12.30
6747,+13.9,4.4, 96, 80, 00, W/B ,+32.2, 53.2,+30.0, -6.0,340.00,3.3, 12.14
7002,+13.9,4.4, 50, 80, 00, W/B ,+36.7, 29.4,+30.0, -6.0,295.00,2.3, 12.34
^^^^^^^^^^^^^^
this was taken from: Lean W.I. Machine thread in the engine managment and tuning forum... (sorry to rob your data navybluesubaru but i think it will help me greatly understand this setup)

is there anything else i need to know or anything im missing?

thank for the help
peace
josh
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Old 05-05-2005, 11:04 PM   #2
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...josh....I don't mean to be mean....but if you want to have an understanding of this to the point where if all makes sense to you, you really need to do a great deal of research and reading on this one.....if is a fairly simple concept that can get fairly complex.

.....quickly, water cools....turbo'd motors get(real) hot----heat causes bad juju....

...a little water, and in some cases water and alcohol mixed, can do wonders in several ways to keep bad juju from happening and increase performance for relatively low cost----lots cheaper than nawwwsss.

...water/alcohol can be used in NA engines, but the benefits are less.


...and that log you borrowed from the other post is a UTEC(engine management piggy-back computer) log from a pull done by the poster...and THAT is another bit of research you can do.....
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Old 05-06-2005, 12:46 AM   #3
offset
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Go here and read lots...
http://www.waterinjection.info/

offset
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Old 05-06-2005, 12:51 AM   #4
gf8rallywagon
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thank you, and believe me i know that some good research is in order, im just looking for a starting point...

i've seen some threads talking about the water being TBI... is this the case? if so i can see that it would cool the intake manifold, which under boost pressures can get extremely hot... and obviously cooler air is def. better... which also makes sense as to why it doesnt do much for an n/a motor. the water(or water/alcohol mix) being TBI also explains why this isnt harmfull to the engine...

thanx for the reply and any further info...

peace..

p.s. did you by any chance see my other thread about what books and resources are good for obtaining tuning knowledge?
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Old 05-06-2005, 04:01 AM   #5
Richard L
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Quote:
Originally Posted by gf8rallywagon
Ok, so i've been reading on here a little bit of the tuning threads, and i keep seeing things about water injection...

My question is, what the hell are we talking about? please forgive my ignorance but if it is exactly as it sounds then we are injecting water directly into the cylinders (or in combination with the fuel mixture)... From my learning (which i admit is limited) water doesnt burn. And an unburnt liquid is not compressable (this is the basis of hydrolock, correct). Now are we talking such limited amounts of water, as in a fine mist, that it doesn't cause any possible harm? if so i can see the main benifit, cooler cylinder temps... is this correct? are there any side benifits to this? also is this type of setup meant for only turbo cars or could heavily modded n/a scoobies also benifit from this? and can anyone explain this:
, , , ,Load,Knock, , , , Mod, Mod , , Mod,
RPM, MAP ,MAF,TPS,Site,Count, AFR, Ign#1, Inj#1, Ign, Fuel,Boost, MAF, WB, psia, V , % , , , , deg , duty , deg, % ,(CL) , V, O2 ...


is there anything else i need to know or anything im missing?

thank for the help
peace
josh
I will put in my 2C if you don't consider the comment to be too over complicated.

Water injection's sole purpose is for cooling - nothing more nothing less.
This is the very point that has sparked many arguments over the internet
discussion groups for years, I am sorry to say that the concept has never
been fully exploited and understood.

A factory-produced engine will run perfectly and produce good power and
clean emissions without injecting water or alcohol. This is a valid
statement and not many will dispute it. But it will only hold true if the
environment is ideal. Taking a normal engine to work in an extreme hot
ambient conditions and high payload, the engine will suffer from all sorts
of performance losses due to the in-build self-protection mode. The ECU
will first retard the ignition when the sensors detected high air
temperatures, high water temperatures and knock - this first line of
defense works well in the short term. But if the condition persisted, the
engine will inject extra fuel for cooling purposes.

When you come to the turbo and supercharged engines, the engine will suffer
twice as much stress then those previously stated. Further more, if the
engine in question is being turboed or supercharged by a third party bolt-on
kit offered on the market without any in-build self-protection provision,
you are really asking for big trouble. Some aftermarket kits do offer
intercooler or some form of fuel enrichment device to supplementing the
original injector - don't forget that the extra fuel from the original
in-built "fuel dumping strategy" has already been used up to fuel the extra
air provided by the force induction system.

As you have already mentioned that one should not tune the engine
beyond the knock threshold or unnecessary timing retard.
If this is the case -water injection has no place in this type of tuning method.
Why not just buy a factory made turbo car and just leave it alone -no tuning is required.
Water injection is for those who want to venture further, much further than just
put a rising rate fuel regulator and turn the boost up and fewpounds.
Sooner or later, your knock threshold will be reached again, by
then you are firing the engine at TDC and run an air fuel ratio of 5:1 and
the size of the intercooler measure 6 feet by 12 feet. Then come a point
that matter what you do, you have arrived at the final barrier...

Water, with its huge latent heat property can now be used effectively to
enable you reclaim you timing loss and run correct air/fuel ratio and at the
same time keeps the engine cool without bored washing and increase cylinder
wall wear. What more can one ask for? Some group of people still regard
this strategy as "snake-oil" and not to be considered.

Some mentioning of water displacement of O2 inside the combustion chamber
and loss of oxygen will result. Consider this, dumping six-times more fuel
to achieve the same cooling effect as water will also alter your air/fuel to
such and extent that it will no longer burn properly, more power will be
lost. Which method displaces more O2?

Combustion temperature (EGT) should be kept between 850- 900C for cast
pistons and 950-975 for forged pistons with injection. Injecting water is
for lowering the destructive combustion temperatures (EGT: 900c upwards)
it is a common mistake and often mis-interpreted as bad for power production,
used by many anti-water injection tuners. There is a place for water injection
in the modern tuning world.

Last edited by Richard L; 05-06-2005 at 04:12 AM.
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Old 05-06-2005, 10:05 AM   #6
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......

Last edited by Uncle Scotty; 05-06-2005 at 10:14 AM.
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Old 05-06-2005, 04:30 PM   #7
hippy
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Here's the way it was explained to me, sorry for repeating andything other people have said.... On turbocharged engines like wrx's, it is normal practice by aftermarket tuners and by the factory to run rich air/fuel ratios at boost. By rich, I mean a bunch richer then 12 to 1 a/f ratio(anywhere from 10.5 to 11.5 is pretty normal for tuned wrx's and sti's). The extra fuel beyong 12 to 1 will never get burned. It's there to absorb heat and slow the combustion down so the engine can perform safely. By injecting water into the air going into the engine, we're able to run leaner a/f ratios and use water as the cooling agent instead of fuel. This is nice since water is much better at cooling then fuel is, and it can't spontaniously combust like fuel can. Cooling the engine with water has the same effect as fuel, but to a greater extent and with more advantages. Here are some of the advantages....

1)Better fuel economy at boost because of leaner a/f ratios. This lets a water injection system pay for itself in the long run.
2)Since the fuel system uses less fuel at boost with water injection, it's like having a larger fuel system capacity.
3)Has an intercooling effect(cools the air going into the engine) which is like having a larger intercooler.
4)Less chance of detonation which helps get more power when tuned correctly(like having higher octane fuel)
5)Larger cooling system capacity, like having a bigger radiator
6)Steam cleans the inside of the engine

peace
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Old 05-06-2005, 10:26 PM   #8
gf8rallywagon
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all this is very helpfull, thank you to all, any more would still be greatly appreciated as i am always trying to learn more...

what is the one thing that usually sways non-believers of WI to think about it as a valid concept... just curious in case i ever have to get into a debate...
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Old 05-06-2005, 11:22 PM   #9
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Quote:
Originally Posted by gf8rallywagon
thank you, and believe me i know that some good research is in order, im just looking for a starting point...
this should keep you busy for awhile:
http://www.aquamist.co.uk/phpBB2/index.php

http://not2fast.wryday.com/thermo/wa..._chemistry.txt
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Old 05-06-2005, 11:24 PM   #10
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Quote:
Originally Posted by gf8rallywagon
all this is very helpfull, thank you to all, any more would still be greatly appreciated as i am always trying to learn more...

what is the one thing that usually sways non-believers of WI to think about it as a valid concept... just curious in case i ever have to get into a debate...

1)Better fuel economy at boost because of leaner a/f ratios. This lets a water injection system pay for itself in the long run.
2)Since the fuel system uses less fuel at boost with water injection, it's like having a larger fuel system capacity.
3)Has an intercooling effect(cools the air going into the engine) which is like having a larger intercooler.
4)Less chance of detonation which helps get more power when tuned correctly(like having higher octane fuel)
5)Larger cooling system capacity, like having a bigger radiator
6)Steam cleans the inside of the engine

alll of the above.. dude..
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Old 05-07-2005, 01:08 AM   #11
VTsuby
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1 Water has an octane rating that is infinite for our purposes. You would need compression that woulds snap arp studs like maples in an ice storm to get water to ignite. Since you can create virtually any octane you want with mums instead of dom water injecting is great for broke na people
2 Water is a byproduct of combustion so it already is in your engine. No need to worry about more when you turn your engine off the last water injector pulse is far in advance of the engine stopping since your cyclinders are several hundred degrees c that last bit of water evaporates
3 Cylinder temps can drop by over 800F

My teacher was involved with a sierra cosworth motor where they found that they could make more power and a better curve if they stepped up the water and lost the intercooler, it made greater than 750hp

They also noticed the ports in the head where cooler something you won't get with intercoolers. Underhood temps also dropped significantly from the loss of all the piping and cooler

I'd like to run an engine excessively lean and see how much steam generation is worth

A more technical explanation for water injection (I haven't taken thermo yet just chemistry). Atoms of a gas on an atomic level are very excited meaning they are moving very fast if they accelerate more, the temperature increases because of the "friction" caused by the collisions. A gram of liquid water requires 4.182? joules to raise its temperature by one degree celcius where as gasoline is 1.2ish joules? (highly technical) Since two fluids of two different temps when mixed will try to reach a mean temperature also meaning that the atoms try to reach an equivalent velocity. During compression the temperatures of the charge are increasing the atoms of the gas are moving faster when water is introduced into the situation its cold slow moving atoms interact with the fast moving atoms. The atoms of the gasoline are like crashing into a first generation corolla most of the energy of the heated gas is conserved. A water atom is like a maybach it takes alot more gas energy (heat) to get it to move.

Last edited by VTsuby; 05-07-2005 at 01:33 AM.
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