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Direct Port Water Injection
http://www.gt4dc.co.uk/forum/viewtopic.php?f=1&t=938		 Page 1 of 1
Author:  Snakeloa [ Fri May 12, 2006 12:29 am ]
Post subject:  Direct Port Water Injection
Hello everybody,

i hope you can help me. I have got a question and would like to ask you for your opinion.

I would like to add an Water injection (i will sell my old one) and i am
looking to get a new Water Injection.

Please take a look
here:
http://www.enginerunup.com/street-car-k ... rod_22.php

This is a direct port Water injection with 4 injectors and checkvalves for
each runner. The kit is controlled by the new Varicool controller (you can
even hook it up to a laptop).

The other kit would
be:
http://www.enginerunup.com/big-turbo/di ... rod_40.php

With only one injector, one checkvalve and the same controller

Price is nearly the same. 489 to 499 $

So here are my questions:

Would you recommend the direct port option? Like that the spray or mist
would be the same in each cylinder! It might be hard to fit these 4 inch
long brass parts there as there is not a lot of space. As i would use one
injector per runner i could go for finer nozzles and that means finer
atomisation (= better results?)

The one injector option could be mounted into the throttle body or somewhere
there. That would mean it is an area easy to reach. Less part less option to
lead to a failure? But maybe the spray would be to rough ( well i could use
two injectors) and would it be delivered equally to each cylinder?

thank you
Joerg
Author:  krude [ Fri May 12, 2006 8:51 am ]
Post subject: 
The way I understood water injection fitting was that by placing the injection point closer or further away from the combustion chamber you get different cooling results by cooling different elements.
I.E pre CC or FMIC the water was near enough evaporated by the time it hit the combustion chamber which gives the result of cooling the air going into the combustion chamber, pre butterfly will allow the air & water to mix enough cooling the combustion chamber as opposed to the air.
Different distances between the said 2 points will provide different mixture rates of the air & water giving you tuning degrees between cooling the air or in cylinder cooling.
Where they have mounted the injection point will mean there is a very short distance for the water to mix with the air pre combustion chamber.

IMHO you should be looking for the injection point to be around the throttle body area or the I/C/FMIC to throttle body pipe.

But then it depends on what effect you are looking to have I suppose.
There is a good write up somewhere on the aquamist site that explains it all www.aquamist.co.uk
Failing that someone like Datajon, Sirius or Kris might be much more informed about it all.
Author:  Snakeloa [ Fri May 12, 2006 9:50 am ]
Post subject: 
Thank you Krude for your information. Anybody else please feel free to add their 2p.

I am not sure if the direct port will fit in our applications as we have not sooooo much space there. But on the other hand the mist would be much finer and that again would be a benefit.

Krude the two points of mounting you described: How will it affect the mixture rate? And what effect can i expect out of cold air or an cold combustion chamber. I mean where will be the difference in the end.

cheers Joerg
Author:  mook [ Fri May 12, 2006 10:26 am ]
Post subject: 
I'm not sure I would use water injection to be honest, and if I did, it would be to cool the air as opposed to in cylinder cooling.

I've always seen it as a bit of a crutch, something that could go wrong and the result of it going wrong means the engine goes bang. It also needs to be remembered that adding water into the mix will mean you'll need to up the boost to get more power - the water takes the place of air/fuel, so keeping the original boost level will actually reduce power. Simplistic I know as you could probably do more with ecu mapping and cam timing - but once again, you'd be adjusting the system so it can only run safely with the water included. Don't run out is my advice :o

That aside, if you're looking for in cylinder cooling I'm pretty sure direct port would always be the best option - you'd do the same thing for fueling or nitrous after all. I finer spray will be a must getting that close to the engine itself, and it would probably be worth placing right at the top of each inlet port to give it the best chance of atomising fully.

Have you got a spray bar on your intercooler? That would help a little.

PS. Your 'work' is nearly complete and will be sent out shortly :)
Author:  krude [ Fri May 12, 2006 10:50 am ]
Post subject: 
http://www.aquamist.co.uk/dc/coollinks3 ... ennis.html

Where do I place the water jet?
Normally immediately after the intercooler unless the intercooler suffers from heat soaking such as the type that is fitted on top of the engine (Subaru, GTI-R, Toyota Celica and etc).

Surely if the jet is placed before the intercooler it will have better cooling effects?
Not quite true. If the air entering the intercooler is pre-cooled, the cooling efficiency of the intercooler will drop due to the smaller temperature differentials between the ambient air and induction air within the intercooler core. Secondly, there is also a possibility that the hot air from the turbo may cause unnecessary vaporisation of the injected water thus taking up precious volume that was intended for the charge air.

Should the water jet be facing the direction of the in-coming air? Two possible locations, if the jet is to be installed along an induction pipe, point it at 90 degrees to the direction of the air flow. Position the jet furthest away form the throttle body as this will enable better mixing and intercooling properties. If the jet is installed at the end-tank of the intercooler, point the jet in such a way that it has the greatest cavity to accommodate the 90 degree spray pattern.

How do I stop the water being siphoned into the inlet manifold during idle as I have to install the jet after the throttle body?
You need to install an inline checkvalve (806-249), it has a crack pressure of 1 bar, so the vacuum can not overcome the valve.

Is it possible for the water to siphon into the engine during the non-running period?
Under normal conditions, the inline pump act as a stop valve, only under pressures over 2 psi will the water pass through the pump. This condition is unlikely unless your water tank is 10 feet above the water jet.


HTH??
Author:  TrackToyFour [ Fri May 12, 2006 1:51 pm ]
Post subject: 
mook wrote:
I've always seen it as a bit of a crutch, something that could go wrong and the result of it going wrong means the engine goes bang. It also needs to be remembered that adding water into the mix will mean you'll need to up the boost to get more power - the water takes the place of air/fuel, so keeping the original boost level will actually reduce power. Simplistic I know as you could probably do more with ecu mapping and cam timing - but once again, you'd be adjusting the system so it can only run safely with the water included. Don't run out is my advice :o


Mook, most tuners map with the W/I turned off and, as you say, it is there as a safety net. Even Adrian still has a small W/I tank on the Corolla to cater for times when temperatures go critical despite his massive front mount intercooler. From my experience you cannot safely run a standard Water to Air or Air to Air Intercooler without W/I on track. You may get away with it on the road but why take a chance?
Author:  Kris [ Fri May 12, 2006 1:57 pm ]
Post subject: 
Seems that locating the WI nozzle post IC on the 205 works pretty well.

The conventional position is in the TB, turbo side, NOT manifold side or you will syphon water out, unless you install more kit.

For me I think that the best place on the 205 is the TB, not pre IC, but then that's just my 2p!

As a side note, I'd fit the smallest nozzle possible to do the job.

I'm not a fan of WI for keeping everything in one piece as if it fails you may have a problem. I like the thought of it as an additional safety margin though :)
Author:  mook [ Fri May 12, 2006 11:12 pm ]
Post subject: 
Don > Fair point, if it's additional safety then it's a good idea, but it does surprise me how many people use it as a tuning aid in itself :o
Author:  datajon [ Sun May 14, 2006 12:46 am ]
Post subject: 
I would suggest having wi installed in the intercooler out section to intake manifold, as well as the inlet runners.

Further more I would also recommend Water spray bar, this will reduce Inter cooler temps as well, not just charge temps.

This sort of set-up seems to be used on most track cars for good reliability.

Another good choice would be to implement safety margins, so when critical temperatures are reach, the ecu will decide which route to choice. Thus helping to reduce engine damage..

if you have not already bought an aftermarket ecu, i would recommend buying one with full features for wi, ws, as well as safety routines , most water injection controllers do not offer such control, just rely on temps & pressure.
Author:  Snakeloa [ Sun May 14, 2006 1:31 am ]
Post subject: 
What kind of ECU would that be? I just bought a Power FC and Datalogit software.

What safety options would you look for when you would choose the use the direct port WI?

cheers Joerg
Author:  Kris [ Sun May 14, 2006 9:08 am ]
Post subject: 
Quote:
I just bought a Power FC and Datalogit software


Whilst the PFC is programmable I don't think it has additional outputs that can be used to control "stuff" e.g. WI, shift light etc

I have seen other ECUs which have outputs that can be utilised to activate "stuff" from e.g. rpm, load, temperature
Author:  Snakeloa [ Sun May 14, 2006 4:47 pm ]
Post subject: 
With the direct port kit i will have a "varicool" controller. I will have to check what it can do and what not.

There are 10 preset programs and you can connect it to a laptop and then you can twist the knobs yourself.

BTW I ordered the direct port solution and will see if it would be a bigger benefit to mount it at the TB or at the inlet runners. If i go for the TB i can use 2 jets and would have 2 spare ones for anyother application ;)

cheers Joerg
Author:  mook [ Sun May 14, 2006 7:52 pm ]
Post subject: 
Marginally off topic - would the Motec M4 Pro be able to control something like an intercooler spray bar?
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