wide ka

Any one had experience of water injection setups and the best place to have the nozzle on a turbo petrol engine

black_jack

Normally its fitted between the intercooler/ chargecooler and inlet manifold, the difficulty is distributing the waterspray evenly to each cylinder, (depending on the shape of the inlet manifold, the waterspray may have a different flow to air and each cylinder may recieve different quantities of water - the old fashiond way to check is a plug chop) sometimes a nozzle is used per cylinder, close to the inlet ports on the head, to inject the same amount to each cylinder

I have not actually fitted a water injection kit to my car but researched/ considered a water/ meth kit, decided against it (complicated, can be difficult to set up, different setup with/ without, water/ meth tank adds weight/ can run out - may be more practical on a pure drag car) and fitted an external waterspray to my intercooler to go with the other temp control stategies (heatwrapped exhaust/ manifold/ vented bonnet/ insulated cold air intake/ electric waterpump)

whizzisat114

iTrader: (2)

Had it on my integrate evolution . Worked well
The nozzle was in the induction pipe just before the throttle bodies iirc but it was 2001
Think aquamist were the market leaders worth looking up there website

Fiesta_Jed

Depends on what you want, I would only inject before the turbo.

wide ka

Why before the turbo?

stevieturbo

best place depends on your setup, intake temps, intake design etc etc.

wide ka

this is my setup at the moment



any help would be great im reading up on it at the moment but first hand experience is allways better

stevieturbo

How much boost are you using ? Are intake temps at a level where you need water injection ?
What compression ratio ? Is your engine knock limited at present ?

If you're pushing the turbo to it's limits, then injection pre turbo can be a good thing. If not, then less so.

If intake temps after the IC are still very high, then injecting between the IC and Throttle can be of help.
If they are low and the injected liquid may not actually vaporise, then port injection may make the most sense. Especially as your intake manifold probably wont promote even liquid distribution to each cylinder

Although with port injection, your IAT sensor will not see the changes, so if any tuning compensations rely on seeing this change, it may be important.

AEM do a flow meter with a 0-5v output, which is the safest way to apply tuning changes when water/meth is being injected. If for any reason the system fails, this is the safety backup. No tuning adjustments will take place. Obviously you need an ecu that can make use of this though.

Aquamist have actually just released some nice nozzles with built in check valves intended for port injection usage. Saves using solenoids to control flow.

Of course it all depends on the complexity of a setup you want. Is it something simple, or fancy ?

black_jack

!st thing that i notice in the picture is the open cone filter sitting behind the radiator & intercooler, without a heatshield or a cool air feed (not as effective as a fully encapsulated filter/ intet anyway)

isolating the intake air from the underbonnet heat/ heat generated by the IC/ radiator by fitting a BMC or venom etc fully encapsulated filter/ inlet (if there is enough space!) or a bonnet scoop etc, would reduce inlet temps in the 1st place,

I also found an intercooler waterspray allowed me to use a smaller, lighter IC, with a smaller internal volume and a lower profile (sitting inder the bumper/ not being "masked" by the bumper - not a problem you have!) although the lower mass of metal (of the realatively smaller IC) means the IC heats up quicker, it looses its heat/ cools down quicker too (lower thermal inertia) the lower internal volume reduces lag/ boosts bottom end power/ torque (realative to a larger IC) but the external waterspray increases the cooling efficiency of the smaller IC, (massively, due to the latent heat of evaporation) so it has the cooling ifficiency/ top end power of a larger IC, but without the larger internal volume/ lag of a larger one

The external waterspray is "safe" and will not destroy/ chew up your sompressor wheel like pre-turbo water injection may, no problems with atomisation and you won't need to have a spare compressor wheel/ turbo handy

What im saying is better to get a proper insulated CAIS and an external intercooler waterspray 1st, (easier to impliment, less drawbacks) then after that consider water injection, as a total overall thermal management system

You will probably have done the same research as i have done, i considered using a 2-stage electronic boost controller, with the 1st stage set up for without water injection, and the 2dd stage with (so they cold be optimised for with without WI) with some sort of warning/ fail safe for if/ when the liquid runs out to switch it to the lower boost (this would depend on the type/ sophisticatin of the WI system used)

You don't mention your intended use for the car, or how big a container you will need, you may not have enough space under the bonnet if a larger tank is required, passenger footwell? - right at the back for better traction?

stevieturbo

Water spray does not damage the compressor wheel, and spraying water onto the outside of the IC offers virtually nothing in terms of detonation suppression.

Plus you're spraying water which could potentially find it's way onto the rear tyres. Not a sensible move.

External water spray is a last resort, and only where the IC itself is already too small, or for very hot climates. And offers nowhere near the same potential as internal water injection.

black_jack

Pre-turbo water injection often damages the compressor wheel, especially if it is not implimented correctly and/ or if the water injection is not atomising - water can be very destructive - there are pictures on many forums showing damage to compressors done by pre-turbo water injection - it was used in F1 (engine only had to last about 2 hours) or drag racing (rebuild after each run)

There could be a drip tray/ valance under the intercooler to stop exess water from reaching the wheels, i have not found this to be a problem on mine i have it spraying in a fine mist and it does not use a lot of water (i use the windscreen bottle water to save weight)

Ive ran the external waterspray for a couple of years - before i fitted it i did not think it would make a lot of difference, i thought it would only be used on very hot days or after a hard run/ before a race etc

Yes, it works great on a hot day, but it also works well on a cooler day, you can get a lot of heatsoak even on a cool day, the turbo compressing that air can genarate a lot of heat, even on a cool day

As the OP has mentioned, actual experience of doing something is always better than googling it/ reading it - i run a cockpit adjustable electronic boost controller - i found i could run more boost with the waterspray, even if it was not a hot day.
i specifically chose to fit a smaller intercooler on my car, i could easily have fitted one twice as big (almost everybody else did) but it would have been heavier,would be partly "masked" behind the bumper in my build, would have had an increased internal volume (increasing lag) and a larger thermal inertia (takes longer to cool down than a smaller one - not a lot of people know that - bigger must be better, right - wrong!)

Water has incredible cooling properties and there is somthing called the latent heat of evaporation which is one of the mechanisms that give it these properties, the waterspray alloys me to run the smaller intercooler (by choice) which gives all the advantages of the smaller intercooler, and the performance of a larger intercooler with none of the disadvantages (in fact it outperforms the larger intercooler in some areas)

I completely agree that internal water injection has (far) more potential than an external intercooler waterspray, but the external spray is easy to do, and works well especially with an overall temprature management strategy

Internal water injection is difficult to impliment, there is a finite supply of water and adding a large tank is going to add significant weight, if the engine is set up for the water injection, its bad news when the water runs out (one way ticket to detonation city) if its set up for w/o water injection, it won't get the potential and thee is little point in it, its gonna run out at some point, and some sort of fail: safe will be required, the 2-stage boost controller could be used, with it automatically dropping to the 1st (lower) boost setting when the water runs out

Injecting the correct amount of water is difficult, with different boost/ CFMs etc etc and the systems can be basic/ cheap or expensive/ complicated. Apart from the setup difficulties and the water running out, potential damage to the compressor wheel, there can be problems with the spray not atomising, stalling, thermal shock, water condensing in the intercooler, uneven distribution between cylinders (would you want the water to evaporate before it reaches the cylinders, if its purely water)

Its an interesting challenge water is a lot cheaper than some of the other things we inject into engines!

Thanks for the discussion - made me think about my own plans - let us know how you get on

stevieturbo

If you choose to implement it badly, then yes it can damage the compressor wheel. Solution, dont implement it badly.
There are also many pictures of people using pre-compressor with no damage, and so far my own has sustained no damage. Although Ive only been using it like that for a few months.

And of course experience is better than google. Ive been using water injection for 20 years. It's simple and it works ! There is nothing difficult about a internal injection setup. There are a wealth of setups around these days, from simple to complex, or you can opt for an ecu controlled system.
It is far far more effective than any external setup will ever be, and hence offers far more potential. IMO the only time an external setup will be of real benefit, is if the intercooler is already poor.
Solution there is to use a better intercooler !

As for it being difficult to implement an internal injection setup, that's just nonsense. it could never be easier these days because there are so many ready to use kits. As for water running out ? If you're that incapable of checking or spotting a low level warning, that's entirely your own problem.
Really, all of the problems you are claiming exist, could only exist in your mind if you've never actually used water injection and you spend too much time thinking about things.
It water runs out or fails to spray, damage will only occur if you choose to let it occur. There are many ways to make it 100% safe

If you choose to build any system badly or poorly, then it will carry bigger risks. the same applies to absolutely any aspect of a modified car. So the simple solution is to do the job properly and the risks will be minimised..

wide ka

thanks for your replys,

i will try and answer some of your questions

compression ratio is either 9-1 or 10-1 its not very low will check though

will be running up to 20psi of boost, but not that level all the time

i am restriced to space and are worried about heat. i want to run water injection to maximise perormance for what i have built

turbo isnt being pushed to its limit so post turbo location will be fine,

ive won a snow performace kit which work with boost pressure on eBay just waiting for it to turn up to see what ive got to start with. it has no nozzle so will need to spec one and buy one.

i wated to run the kit to lower inlet temp but not to change the timing of the engine if that makes sense im not chasing out and out power so dont want to engine to rely on water injection other wise it will blow up.

stevieturbo

At only 20psi, you already have a decent looking intercooler. So charge temps shouldnt really be a problem even at 9.0:1. 10.0:1 is high and your engine will be knock limited and you will need something

So how the system is used will depend massively on that. I would advise using some of Aquamists new nozzles and do port injection. But sounds like you will only need a very small quantity of water.
And unless you are tuning and optimising timing as well, there probably isnt any point in bothering in the first place ( at least at 9.0:1 )
At 10.0:1 you will absolutely need some form of detonation suppressant.

Alcohol Injection Systems in the US make the neatest tank/pump system. I'd have bought that. The boost/progressive controllers are all pretty much the same. Nozzles vary in fitment, but are all pretty much the same except Aquamists. They are the smallest and neatest nozzles. But they have new ones with built in check valves specifically for port injection setups.

If the safeties are tuned properly, there is no reason why a problem with the water injection would pose any risks.

KnoxyGtt

I Had the devils own water injection on my old let corsa and from what i read on lots of different forums for a basic setup it was best to put it before the throttle body but before the cts.

wide ka

Port injection I presume is direct into each inlet port?

If so the engine had direct to head thottle bodies so would struggle with doing it that way.

I will wait until the kit arrives and see what I have.

Will double check the cr of the engine

stevieturbo

port injection simply means 1 nozzle for each port. Doesnt matter exactly where they are situated, as long as they inject equal amounts into each cylinder. Could be in the runner or the plenum