944 Turbo: Water injection + intercooler sprayer
08-08-2005, 04:32 AM
#31
Race Director
Please allow me to bust your ***** a little... I am sure you know this, which is why I am surprised you are doing it this way...I know you are not mapping the intake, which is fine if its tuned for the max duty cycle of the injectors, but the cooling of the IC comes from the evapouration of the water, not the water itself, if you continuously spary water on it, it wont be evaporating when you need it.
08-08-2005, 07:30 PM
#32
I realize that a complete evaporation would be nice to achieve, but unless you have a 100+mph wind tunnel I can borrow I don't know how else to bench test this sort of thing. 
On the same topic, wouldn't some water droplets on the intercooler be beneficial? I'd liken it to the idea of perspiration on human skin.
On the same topic, wouldn't some water droplets on the intercooler be beneficial? I'd liken it to the idea of perspiration on human skin.
08-08-2005, 07:46 PM
#33
Race Director
Its actually pretty easy to bench test 
If you have a couple of temp sensors... autospeed actually experimented with the duty cycle on one of their projects and came up with some pretty intersting data, the link is around somewhere...
As for the droplets, atomisation is not as important on the IC as it is in the intake, though still desirable, the more atomised the water, the quicker it will evapourate as there is greater total surface area... the persipration on human skin is solely for the purpose of being evapourated. No cooling comes from the droplets themselves. Try this, put your hand under a tap running some room temperature water (like what your washer res will be, but probably cooler!), does your hand feel cooler? Now take your hand out, then blow on it to evapourate the water.
If you have a couple of temp sensors... autospeed actually experimented with the duty cycle on one of their projects and came up with some pretty intersting data, the link is around somewhere... As for the droplets, atomisation is not as important on the IC as it is in the intake, though still desirable, the more atomised the water, the quicker it will evapourate as there is greater total surface area... the persipration on human skin is solely for the purpose of being evapourated. No cooling comes from the droplets themselves. Try this, put your hand under a tap running some room temperature water (like what your washer res will be, but probably cooler!), does your hand feel cooler? Now take your hand out, then blow on it to evapourate the water.
Last edited by NZ951; 08-08-2005 at 08:10 PM.
08-08-2005, 07:53 PM
#35
Race Director
Oh I should also add, use the same logic as for your intake water injection, you are not injecting water for the water itself to cool down the charge and combustion chamber, its the transformation process from water to steam that does tis. The water requires heat energy to transform into steam, so this heat is taken from the track from where the water is injected to the combustion chamber. Thats why people add methanol, it transforms quicker...
08-08-2005, 10:21 PM
#37
NZ - Yeah, that makes sense. Time and testing will tell. I might just put an air temp sensor in the hot side of the IC and another post-throttlebody on the intake manifold.
LOTS of guys go the cheaper route: venting CO2 onto the IC. Same hardware as a N2O setup but much cheaper (and more readily available) gas. Works rather well.
Originally Posted by WesM951
Intersting..
Kinda OT, but what does purging NOS onto the IC do? Same effect?
Kinda OT, but what does purging NOS onto the IC do? Same effect?
08-09-2005, 03:00 AM
#38
Instructor
Hey Guys,
Sorry if I am hijacking. I just saw this post and thought I would chime in.
I installed my water injection over the weekend. I have not fine tuned anything, but so far I like what I feel. I am running a Snow stage one. Right now it is injecting way too early (maybe 4psi?) but there is no stumbling or running issues. I went through a gallon of washer fluid in a few days already (and I was not working it that much). I really like how the car feels. One interesting note: I can actually watch the temp needle drop after a few on-boost seconds. I think I am injecting too soon and possibly too much, but it definitely feels better than before. I will dyno it later this week. I will post pics in a few days if I get a minute to take them.
Sincerely,
j
Sorry if I am hijacking. I just saw this post and thought I would chime in.
I installed my water injection over the weekend. I have not fine tuned anything, but so far I like what I feel. I am running a Snow stage one. Right now it is injecting way too early (maybe 4psi?) but there is no stumbling or running issues. I went through a gallon of washer fluid in a few days already (and I was not working it that much). I really like how the car feels. One interesting note: I can actually watch the temp needle drop after a few on-boost seconds. I think I am injecting too soon and possibly too much, but it definitely feels better than before. I will dyno it later this week. I will post pics in a few days if I get a minute to take them.
Sincerely,
j
08-10-2005, 02:33 AM
#39
Rennlist Member
Unless you're running 30 plus psi boost, 20% water amount is way, way too much water!
When that amount of water kicks in, it'll feel like the power all of a sudden got dampened; like it's running overly rich. Yes, of course, your engine won't detonate, but what would be the point if your power doesn't rise with boost.
We're talking intake injection, here; and with it tuned correctly, the IC sprayer is useless by comparison.
When that amount of water kicks in, it'll feel like the power all of a sudden got dampened; like it's running overly rich. Yes, of course, your engine won't detonate, but what would be the point if your power doesn't rise with boost.
We're talking intake injection, here; and with it tuned correctly, the IC sprayer is useless by comparison.
08-10-2005, 02:52 AM
#40
Race Director
I have to disagree here, we are talking a proportion of fuel, irrespective of boost the proportion stays the same. The norm is between 20-25% water of the amount of fuel. So 10psi or 30psi it does not matter, the ratio stays the same. Yes there is more heat at 30 psi, but I dont see 20% of water being way too much at 20 psi for example, the heat is still significant then.
08-10-2005, 07:44 PM
#42
Rennlist Member
So, NZ,
you know that 20% water is the norm because you tried and tested it and found it works great at that level?
I'm guessing you read your theory somewhere.
you know that 20% water is the norm because you tried and tested it and found it works great at that level?
I'm guessing you read your theory somewhere.
08-10-2005, 07:49 PM
#43
Race Director
Tommy,
No, 20% is the norm because thats what most people claim they inject, somethng would not be the norm because just I use it. But yes I have tried and tested it, not on my own car, I have got an electromagnetic pump in my garage wating for my new computer to install in my 944 turbo.
Of course I needed to read the throey and practical advice to get an idea on the norm percentage injected... I could not know that any other way.
No, 20% is the norm because thats what most people claim they inject, somethng would not be the norm because just I use it. But yes I have tried and tested it, not on my own car, I have got an electromagnetic pump in my garage wating for my new computer to install in my 944 turbo.
Of course I needed to read the throey and practical advice to get an idea on the norm percentage injected... I could not know that any other way.
08-11-2005, 10:48 PM
#45
Rennlist Member
Yeah, read carefully; for the most part, the Aquamist info assumes no intercooler
"10% to 25%"
What makes you guys think you need to be on the high end of the scale.
The "more is better" concept has no merits, here.
"10% to 25%"
What makes you guys think you need to be on the high end of the scale.
The "more is better" concept has no merits, here.