Char1ie

iTrader: (6)

As per the thread title, I know nothing about water injection but have been speaking to knowledgable people about fitting it to my 2WD Sapph race car which runs a restrictor. As I understand it the ECU will inject water into the plenum as a mist when the air in the plenum reaches a certain temperature. Water cooling reduces the air temp allowing for more power and reduces EGTs.

Clearly I'm a novice but I think I have the basics. Now I have to work out what sort of system I need and the likely cost - if it's too high I won't bother.

Has anyone fitted water injection to their Cossie and if so, what system did you use, or was it custom built. Just the list of options at the ERL site is overwhelming: http://www.aquamist.co.uk/sl/plist/frm-4.html

And what sort of cost are we talking for the bits?

Thanks all,


Charlie

pacwest

I used it for years. I went through a lot of water...

I had a home made setup of a high pressure pump, a pressure switch that came on at 1 bar and was injected by a fuel injector.

I had very good results with this I felt. My injector was the same flow as my fuel injectors and I was quite sure my water pressure was 2.5 bar above inlet pressure. My water tank was pressurized by the inlet pressure with a one way valve.

I would certainly recommend you map the water injection. Play with flow and pressure.

Remember that a good percentage of fuel at WOT is there strictly to cool the cylinder walls and doesn't get burned. Water injection if as reliable as your fuel delivery allows you to run leaner at these higher levels so mapping it against your fuel delivery is key.

Again, the system MUST be as reliable as your fuel system. No dodgy wiring or crap components. Aquamist is a good solution. Water levels MUST be monitored if mapped against fuel.

Rod-Tarry

Yes i use it when charge air reaches 40deg its switched on by ECU.
use a 50%/50% mix water/methanol its far more efficient & hence you wont need as much.
I use the ERL system, The Jet size will be depend on how big your problem is. Use an indicator LED so you can monitor when its on.
It should rarely come on if it does its the Intercooler you should be looking at not masking the problem with WI. Its a compromise WI will lose Power but not as much as when Charge Air gets out of control.

cossie col

how come you lose power Rod, thought with 50% methonal it would burn better and be like that cold misty morning feeling when car feels like it goes better but you know more than me.

Was just about to do same thing so intrested in this

What is the best tank to use and can you get one with level indicator like screen wash so you know when it gets low

pacwest

Actually straight distilled water sucks more heat out of the system and is more efficient. 50-50 mix is great for cold weather though.

Think how quickly water evaporates compared to alcohol. You need to put more heat into water to make it evaporate. It can then take more heat OUT of the charge.

Air charge temps are no match for water. Especially intake valves. You see significant cooling with distilled or at least filtered water.

turbotoaster

also it seems most people over in the uk dont seem to know about pre turbo w/i

most run it after the intercooler but usa and oz run it pre turbo, think about it though as it makes most sense.

You want to take heat out of the charge when its at its hottest, no point letting the intercooler do all the work and the w/i mopping up the effects after.

Because of the high inlet temp coming out of the turbo you can add alot more water than normal so the cooling effects are even larger. Im not talking about the pipe between the cooler and turbo neither, im talking about between the air filter and turbo as your using the turbo to atomise the water better by sending it through the fans.

For your setup im thinking you need about 300cc/min of water to be effective, will help your EGTs loads

I can show you some examples if you like to help

Danny @ Enhanced Performance

iTrader: (3)

iv been talking about this alot lately and reckon pre turbo is better than wi at inlet...please share some ideas...


thanks danny

THEDMAN

iTrader: (1)

Give the WI a miss and go with the old fashioned illegal rally team trick of CO2 or NOX in fire extinguisher bottles!

Any former Lancia team boss would give you the details.................

jammerrs

these that had to change there 'fire extinguishers' at every service stop, best way to do it

how does the water not get into the enigne then and hydrolock it?

CossieRich

iTrader: (1)

Because its a very very fine mist and evaporates as it cools the air.

jammerrs

right gottcha, cheers

CossieRich

iTrader: (1)

Its usually triggered when air temps reach a certain temp AND a certain boost level is reached

GARETH T

water slows the flame progression! most people overlook this!

foreigneRS

i don't understand how that could then pressurise to 2.5 bar higher than the inlet pressure?

think you mean N20, commonly reffered to as NOS, as NOX is something completely different

OldDan

Can I ask why people don't use this on N/A cars?

marky_g

i hace aquamist kit on my rst 20psi all day long no issues, only use water tho not water methonal

GARETH T

ill try and sum it up in a few words when used on a n/a engine,,, ummmm,,,,its shit

only joking ,,, why would we want to take up valuable space in our combustion chamber with water, when this space could be filled with a nice air/fuel mix

OldDan

Understood.

Is it a case of not having enough heat in the inlet for the water to make a difference basically?

GARETH T

well generally we use water injection to surpress det by slowing the flame progression. the removal of heat gains are normally offset by the wasted space of the water in the mix

OldDan

Cheers!

turbotoaster

well distance between the compressor blades and the jet is the most important thing, too close it wont atomise correctly, approx 4 inches is what a lot of Aussie guys do

Id say for your power your looking at spraying in 500cc/min, but its very important you have strong ignition as it will be no good, what have you got currently for giving your plugs more bang?

theres a guy on rx7club with a proper ghetto setup blowing 500cc of water into his turbo when running 23psi of boost on pump fuel, without it hes limited to 14psi, its a mechanical setup, no pumps or electric in sight, in theory extremely reliable, i have pics of that if you want to look at it, might be safer for a racecar, but you will need a BIG bottle to hold all the water

Ive also seen 32psi on pump fuel but that was with 1600cc of water, a guy from oz doing it and he put down over 700whp on a gt42 (which for an rx7 is like a god)

Its the equivalent of Rod running 1100bhp on his cossie engine on pump fuel.

Is there anything you would like to know in particular that i can help with?

Alps Pacino

are these aussies and septic tanks not going to have bigger issues than us in the uk due to the climate difference ?

foreigneRS

as it's a race car, unless you are limited to the original components, then surely you always have enough speed for a proper intercooler to be the best option?

Alps Pacino

i've always been led to believe WI isnt a replacement for a good cooler but more an extra, if you know what i mean?

Touring Car Spares

iTrader: (6)

Nope , i had exactly the same issue running a Production saloon car Sapphire , you were NOT allowed to upgrade the intercooler. Added to the additional heat that backpressure in a restricted T3 causes and you will need an alternative like W.I .
I used a huge Transit plastic bottle and twin washer pumps with a jet on the outlet of the Intercooler ,this did bring the ACT's down and gave noticeable gains on anyhting other than red hot days ,used a whole bottle per 20 min race too .

Char1ie

iTrader: (6)

OK, thanks all for your input. As Tony has said I can't use a bigger intercooler as I'm limited to the 4X4 unit.

Ignition is by coilpack. Wasted spark run from Gotech ECU but may change ECU as we're experimenting. 071 plugs.

Pre-turbo water injection sounds like a good idea. I guess there's some experimentation involved on a Cossie unless anyone else has done it already and has details of where to locate the injector? Four inches in front of the turbo sounds like a good starting point. And the ECU would only fire the injector when the car is on boost and the charge temp reaches a certain point.

500cc per minute is 10 litres for a 20 minute race if the car is constantly on boost. So a 15 or 20 litre tank filled with distilled water sounds sensible.

Also thinking about running spray jets on the outside of the intercooler. Anybody done this? Any pics of WI and intercooler jets?

Thanks all,



Charlie

Mike Rainbird

iTrader: (3)

This explains the use of water injection in road cars. It's a popular misconception that water injected into the combustion process is the miracle cure for allowing monstrous boost pressures and protection against detonation. However, the correct use for water injection in a road car, is purely as a form of charge air control. Any other use is asking for trouble - should the water supply run out, the jets become blocked or the pump fail whilst being used to prevent detonation, then the engine will simply follow suit pretty sharpish. By using it as just a form of charge air control, should it fail, then the only consequence is a slight reduction in power as would originally be experienced without the WI.

So when should water injection be used? Well in my opinion, ONLY when you have exhausted all normal methods of cooling the charge air. By this I mean, when you have got to the stage where you have run out of room to fit a larger capacity intercooler, but are still suffering high temps (you really can't beat a big air to air intercooler for charge air control). The reason being, that injecting water into the combustion process actually LOOSES you power (as obviously fire and water don't mix nicely!). So why do we use it then? Well, when the charge temps reach a certain temperature (ECU dependent), the ECU switches to a charge air retard map (sometimes with reduced boost as well) or simply chops several degrees out of the ignition timing. Obviously this has a severe effect on power as well as developing excessive heat in the combustion process and the car suddenly feels very flat. Controlling the charge temperatures by injecting water into the combustion process, although losing you some power, doesn't lose as much as you would by allowing the temps to climb to the charge air retard point. So you are simply keeping as much of the power as possible as much of the time as possible. The next question to be asked is at what temperature point do you inject the water? Fortunately Ford Motorsport carried out all the necessary research as part of their late 80's / early 90's rally program and the optimum temperature to inject the water is at 42°C. Much later than that, and the injection of the water fails to stop the charge temperature from climbing and any earlier, it fails to evaporate enough (and it is this heat exchange process that cools the air) and can cause misfires as the fine mist collects into droplets and acts as an extinguisher on the spark (which is why pure boost controlled systems are obviously flawed, because in low ambient temps, the WI won't be needed as the intercooler should be capable of maintaining an acceptable temperature). The Ford developed system switches off if the temps drop below 38°C and / or boost drops below 7psi.

It is also a good idea to have the water injection controlled by a pressure switch so that the pump doesn't switch on unless it sees in excess of 7psi of boost as well as the temperature activation point and this prevents the pump switching on in heat soak situations (as anyone with an ACT gauge will notice occurs in slow moving traffic or if the car is switched off for a short period and then restarted). So once the water is injected at the correct point, it manages to hold the charge air temps to around 40 – 44°C. This temperature is considered as close to optimum for intake temps for a turbocharged car and is as good as you can expect to see in 20+°C ambients at full chat - any lower than that and you obviously don't need water injection in the first place.

How to get WI on your car: If you have a L8 (4x4 Sapphire ECU) or P8 (Large turbo Escort ECU) and this is equipped with a Pectel board, then this already has the water injection feature built in and just needs a relay connected to pin 12 on the back of the ECU and the relevant water injection hardware (reservoir, pump, filter, check valve (to stop boost from pressurising the tank), suitable hose and jets). If you don't have one of these ECUs or it isn't equipped with the necessary Pectel board, then all is not lost, as you can still have water injection controlled by a SECS monitor or one of our ACT gauges (with the suitable upgrade kit). See my website for details .

Relevant hardware:
1. Water injection jets (ideally two 0.6mm jets for a finer spray, as per the WRC cars):
2. Check valve - this is a one-way valve and goes just before the jets and stops the boost pressure from backing up and pressurising the storage tank.
3. Filter - this stops any crud that builds up in the tank from blocking the jets and need s to go before the one-way valve.
4. Water injection pump - this is the same arrangement as used by the works cars and runs at a massive 6.8 bar pressure, this is because with the engine on full boost, it still needs to be able to generate sufficient pressure to combat this as well as being able to deliver good atomisation of the water. At full chat it can flow 7.6 litres a minute!
Obviously you also need a tank for the water supply as well.

Char1ie

iTrader: (6)

Good stuff, thanks Mike. I've been doing some reading and I think we'll try water injection pre-turbo by adding an injector into the pipe between the air filter and turbo. This method seems to give good results and as long as the water atomises correctly there shouldn't be any additional wear on the turbo.

I think the challenge will be getting the ratios of volume, pressure, injector size and distance away from the turbo right.

Charlie

Mike Rainbird

iTrader: (3)

Hi Charlie,
According to Ahmed, the problem with injecting it pre-intercooler is that the water condenses and collects in the intercooler and reforms back into droplets, this is why the works teams always injected it post intercooler.

Got to be worth experimenting with to see for yourself though .

turbotoaster

i think you make a good arguement for traditional water injection but the points you make in terms on temps in which to turn it on and what happens when its to cold backs up the theory of the pre turbo route.

Pre turbo is setup purely on boost pressure normally, it can be setup with temps but to be fair theres no point really. The temp coming out of the turbo is always gonna be hotter than 40c so you may aswell use it purely on boost pressure.

Say for example the temp of the turbo is 140c, with pre w/i it becomes 90c, thats much more beneficial for the intercooler to deal with.

I suppose i shouldnt say traditional for mikes method as pre w/i was developed in WW2 so thats prob the original way it was designed.

mechanical system, no pumps required for this
http://www.rx7club.com/showthread.php?t=807016

how to take the pre w/i to the extreme
http://www.rx7club.com/showthread.php?t=863250

theres some really good info in that if your interested in pre w/i, its a big thread but i really suggest your read it as alot of information is relevant for any turbo charged car, piston engines included

Touring Car Spares

iTrader: (6)

Charlie .the last point is another grey area , years ago when i raced we were told we couldnt spray on the outside of the intercooler,any fluids emanating from the car were seen as "leaks " and were Black Flaggable offences , i do know a few guys that have done it recently but dont know how the scrutineers allowed/not allowed it .In short check !

Mike Rainbird

iTrader: (3)

Weren't the WW2 aero engines non-intercooled, so obviously the WI would operate pre-intercooler - as this was the only method used to cool the charge temps? .

Also, I wouldn't be comparing a rotory engine with a normal piston engine, as these engines suffer hugely from rotor tip issues, so they need to be injecting water nearly all the time on a high power engine to keep it in one piece (also they are using it for knock protection, which IMO is not the way to go, as when you run out of water, BANG goes the engine ). Being in Australia as well, they're constanly seeing ambient temps of well intop 30°C, where we very rarely see that. Think of the size of the tanks they must need . Great for drag racing, but not really suitable for track / street use (unless only short journies are undertaken).

On a small intercooler it may be worth while, as these will see 60°+C with even only 280bhp , but I wouldn't be doing it on a car with an efficient intercooler for the reasons I have highlighted.

I can however, see the benefits on trying it on Charlie's set up .

turbotoaster

Hence why i mentioned about it is relevant for all turbo engines, im not just talking in OZ, they do it in most of USA aswell(including canada where its not exactly a hot place)

Theres a massive power evo that uses it pre turbo(1000whp) running 50psi of boost as because its pre-turbo they believe it is taking heat out of the turbo at point of compression which means that it isnt falling off the comp map as bad, turbos push only so much air on any setup before they end up creating to much heat that the air density goes down and you make less power, by cooling that air at point of compression you can push the boost higher and still make power.

Now that isnt gospel but it seems to be alot of tuners over in USA are going down this route, and you have to admit they know how to make come quick passes down the strip.

Yes rotarys need it for knock protection above 1bar of boost as you try to keep 700bhp together with a 2mm piece of metal, any det and it destroys them.

But why would a piston engine be any different, surely if you can hold off det with w/i and allow more boost then its all win and to be fair if your getting to the point where you need water injection on an engine if you let it run dry its your own fault for being a dumbass(only my opinion)

In charlies case if hes racing for say 20mins and on a lap is 70% throttle for the lap at 500cc then thats 7 litres of water a race, just stay off the cakes for a couple of months and he can still maintain the same weight in the car.

Obviously if he can run the car at full boost without w/i then adding it just helps a little, its where no w/i limiting his boost is where he will see big gains.

Char1ie

iTrader: (6)

Tony, having read a bit more I think the external intercooler spray jets may be overkill. The water injection pre-turbo should cool the air sufficiently. I have been reading a few threads on the Aquamist (ERL) site that suggest that in some cases you can do away with the intercooler (not on my car).

turbotoaster your suggestion makes sense - just switch on the pre-turbo water injection at a certain boost point. We'd probably measure the charge temps at the plenum to monitor.

The Aquamist ERL forum is a good source of info but there is a lack of clear info and a lot of debate about theory. I'd like to find a document called pre-turbo water injection for the Sierra Cosworth.
http://www.aquamist.co.uk/phpBB2/viewforum.php?f=13

Charlie

Char1ie

iTrader: (6)

Running dry is one thing but the pump could fail, electrics could fail, etc etc. I have read that one of the advantages of pre-turbo water injection is that there are a couple of seconds between the water running out and the engine detting because there is still moisture in the intake. So if you can use a sensor that sees water flowing into the injector, when the sensor sees no water the ECU can cut the engine or light a massive red lamp.

7kgs is OK. I weigh 100kgs - you're right about the cakes!



Charlie

turbotoaster

im sure i can have a hunt tonight for you when i get in from work on the big power evo guy, as they are comparable results.

Have you reached the point currently where you cannot run anymore boost because of det/high inlet temps?

Water injection like mike says is only worth it if its needed, what makes you currently think you need it

Mike Rainbird

iTrader: (3)

Because you only need to do this when you are running a turbo at such extreme pressures. If you note, they are all over the moon that they are getting 40-45°C ACTs with this method, and if you check my post above, this is what POST intercooler WI is achieving (albeit on a less radical boost arrangement). Therefore I would only be doing this IF I was failing to achieve these temps by any other method, as you can end up with an intercooler full of water .

turbotoaster

obviously there is a limit to how much water you can chuck in there before it doesnt atomise but a guy throwing 1600cc of water into his turbo hasnt had this problem with an intercooler full of water so id say for charlies level of water needed he will be fine, they even asked him the same question and he took the intercooler off to check and it was fine and thats at the extreme end of the scale.

Charlie have a look at that first link i sent you, that thread is a guy using the boost pressure in the system to actually inject the water, no pumps, no electronics, nothing, he manually checks the water every so often but in your case for safety all you would need is a low water level sensor and your done.

the best bit is because it uses boost pressure to power it the less boost=less water....more boost=more water

Garage19

Bare in mind that if you run pre turbo WI you will get erosion of your compressor blades over time. The leading edges especially will loose their sharpness which will effect the effeciency of your turbo.

turbotoaster

does aluminum alloy wheels erode with the odd blast of water, id imagine it would atomise and instantly dry so wouldnt make a difference, but ill be honest and say my knowledge on liquid contact on metal isnt that great



quote from the 700whp guy by the way

Afs are 10.8-11 on all boost ranges 20psi and up.

My car has 3 boost settings. 15psi, 25psi, 34psi. On 15psi it does run alot of water so my fuel mixtures their are 11.5-11.8:1 to compensate otherwise it breaks up alot. On the 25 and 34psi setting its perfect.

Egts do not get any higher then 950 degrees celcius unless im on the road and i load it up 2nd, 3rd, 4th , 5th it will go just over 1000 degrees celcius and im sure if i loaded it more it would get hotter.

My old engine use to see egts of over 1050-1100 degrees celcius and never minded it. So im not worried about the EGTs. Ive heard alot of people saying it musnt be over 900 and so on but my experience is showing me otherwise.

What i have found to be most most important is KNOCK, and this is where ive found water to be most effective. IT COMPLETELY eliminates any form of knock. Not just on pump fuel either.
we have tested a wi system on a car running e85 which was running in excess of 35psi of boost and we were picking up knock, setup a basic wi system with a 700cc jet and all traces of knock disappeared.

As for my jet placement.
Its in the front of the turbo. My inlet pipe has 2 jets right in the centre.Youll see the water line feeding it in the pic.

I have tried post turbo. Not as effective