water injection pre turbo

[project_x]

has anyone tried water injection pre turbo??

i have done it on rotary engines with great results, and im thinking of doin it for my 1ggte..

has anyone tried it and how did they go.

the setup that i used was a pumpless system using a airation nozzle(similar to a spraygun) it uses pressurised water and air pressure that mixes in the nozzle and is pumped infront of the turbo.the water tank is pressurised by boost and is switched on via a solenoid and hobbs switch.

a friend of mine makes 580 odd rwhp with a 13b bridgeport at 21 psi on pump gas(i know its a rotary sorry guys), this is around 200hp more than normal

i also tuned one on a mates one and made over 400rwhp at 18 psi with a very mild engine , i have found this to be a sort of insurance as rotarys are somewhat fragile as well as powerfull.

using this simple pre turbo setup seems to be reliable and cost effective.Im just not sure what it does to a piston motor power wise and what people have experienced..

[twentyEight]

I remember an article many years ago in a magazine about water injection/water spray kits running pre turbo, but I can't remember which magazine it was...

After a bit of testing they removed the turbo for inspection and they found that the spray had in fact left lots of fine pitting on the compressor blades, and advised that over a longer period of time, this pitting would cause quite alot of damage to the compressor blades and water injection/water spray kits running pre turbo should be avoided...

[project_x]

I remember an article many years ago in a magazine about water injection/water spray kits running pre turbo, but I can't remember which magazine it was...

After a bit of testing they removed the turbo for inspection and they found that the spray had in fact left lots of fine pitting on the compressor blades, and advised that over a longer period of time, this pitting would cause quite alot of damage to the compressor blades and water injection/water spray kits running pre turbo should be avoided...

i have seen this once before but the setup was a not that good and they had a washer bottle feeding ditectly in and there was no means for the water to atomise..

i have witnesed a setup on a car that has done over 15000ks and no turbo damage at all, the secret is in the amount of water and the atomisation, the benifits i have seen with my own eyes . The amazing thing is after reading the plugs and looking at egts it seems as if the engine was running standard boost, we also ran more timing than normal .

[stradlater]

Ok, well I saw the same article TwentyEIght did...

SO,

You go ahead and run your turbo with water injection infront of it for 10,000k's and I'll go ahead and not. Then we'll compare at the end, sound like a plan?

[thechuckster]

i did this with my old turbo+carbi setup. Isn't ideal as you have relatively large droplets of water hitting compressor wheel. If you can solve the atomisation issue then do-able, but post-turbo is better.

[YelloRolla]

A friend of mine does this with great results, like you have pointed out already though the water needs to be a very fine mist. If it hits the comp in a stream then it can actually cut the comp wheel.

You can add methylated spirits to the water to assist with the atomisation.

[twentyEight]

I'm pretty sure that the kit used in the article had very good atomisation...

[chris davey]

why not just do it post turbo and avoid the chance of stuffing your comp wheel? Is it not just the placement of the nozzle which would have to be changed?

[twentyEight]

Is there any actual advantage of having the spray kit pre turbo?

[YelloRolla]

Pumping against the compressed air will be a tad more difficult, although no more than running a pressure line behind the pump as a compensation.

[STR8 2.8]

why not just do it post turbo and avoid the chance of stuffing your comp wheel? Is it not just the placement of the nozzle which would have to be changed?

but then you'd need a seperate pump, you couldn't just use boost pressure

[stradlater]

I'm pretty sure that the kit used in the article had very good atomisation...

Agreed, that's what I read too

[thechuckster]

my kit just used a fine spray head just at the front of the carbi spraying directly down the throat (CD175 stromberg). used a windscreen washer pump, triggered with a 5psi hobbs switch and a 50:50 mix of water:methanol

Now that i have an intercooler and proper fuel/spark management, i've not needed it.

[project_x]

Is there any actual advantage of having the spray kit pre turbo?

from what i can understand ,

using a pumpless system, there are very few moving parts,less things to clog up, dont get problems when you use methanol but a big one for me is when you see a draw thru carby setup, you see some that acually frost up the pre turbo area and this is what i would see as the big advantage as when you have the water/fuel under vacuum it has an adverse effect on the air as it seems to alter the desity or something, i remember reading some of the supercharged guys commenting that the boost rose slightly, a turbo car would not see this but it may increase the efficientcy of the turbo somehow, there is a thread in another forum if anyone wants to read it i can dig up the link...

i have been recomeded tho use metho or methanol to reduce the chance of water freezing under vacuum( i dont realy belive it tho) i would like to use some methanol for the fuel advantage but

from what i have been told , one of the better post turbo systems is the aquamist, and one guy i know that uses it swears by it .. i think the only drama is the cost factor...

im thinkin of goin this way mainly cause its cheap and reliable, its very dificult to use those two words together usually cheap and sh*& or reliable and expensive.I would like to see if anyone is using this method.

cheers

rob

[project_x]

A friend of mine does this with great results, like you have pointed out already though the water needs to be a very fine mist. If it hits the comp in a stream then it can actually cut the comp wheel.

You can add methylated spirits to the water to assist with the atomisation.

i have heard the same...

they do use water to cut steel i suppose.

[YelloRolla]

There are some specifics to making it work.
For example; are all the cars that are running draw through carby turbo doing the same damage to the compressor as those who have failed with water injection? If not then what is the difference?
Plain water has a very high surface tension, and it doesn't evaporate (and evaporation is what we want to achieve to bring the inlet temps down) all that quickly. So adding a percentage of alcohol to the water helps with both of these issues.

For those who like the numbers. My friends Datsun, fitted with an SR20 running at a C/R of 10.5:1 uses no conventional intercooler, yet it runs 11.0 at 120mph. This is no pretty set up, it uses an atmo motor with a very old T3 on it. I guess that he has something working.

Although I concede that this doesn't address the longevity issue, you can make things work even though the magazine article's authors weren't so successful.

[project_x]

i know its from another forum but a good read

http://www.ausrotary.com/viewtopic.php?t=38929&start=0

sometimes magazine articles are not the be all and end all, but hey information is out there and its up to the induvidual to decide what is best.. i think post or pre has its pros and cons but the water injection pricipal has alot more benifits in general, more so what it does for the cylinder pressure as well.

see what you think

[JustenGT8]

It's not rocket science guys. You have a water droplet hitting softish alloy moving at 100,000+rpm...makes that droplet look pretty solid.

The smaller the droplet the smaller the problem it's that simple.

The only aspect that would worry me (and i swear by WI having run it on my past 2 turbo cars) is the day your pre-turbo water injection setup decides not to atomise well (very cold, partial blockage, act of god) is the day you kiss your compressor wheel goodbye.

[1jzracing]

It's not rocket science guys. You have a water droplet hitting softish alloy moving at 100,000+rpm...makes that droplet look pretty solid.

The smaller the droplet the smaller the problem it's that simple.

The only aspect that would worry me (and i swear by WI having run it on my past 2 turbo cars) is the day your pre-turbo water injection setup decides not to atomise well (very cold, partial blockage, act of god) is the day you kiss your compressor wheel goodbye.

AGREED!

.... maybe usable in a low milage high stress drag application or something where compressor life insignificant

[whatthe?]

So the lesson here is that although more expensive a post-turbo injection kit is going to pay for itself over time?