Re: Water Injection 2007
 

I played around with WI all last year, and learned quite a bit. I'm gonna have to disagree with the argument about WI decreasing AIT temps. Just imagine how fast the compressed air is moving!

I like to agree that the benifits of WI come from the change phase thats going on. :y

Re: Water Injection 2007
 

Yes, and I was impressed at how inexpensive forgings for a Miata are, too. Given how they aren't as fluent as the other tuenarboi cars I was expecting to be sticker shocked, but it's actually really reasonable.

Re: Water Injection 2007
 

pause...

evaporation is definitely not = 0 and its probably not = 100%, but it certainly is somewhere in the middle.

erics put numbers on it with his software. the only thing i've really said is that its between 0 and 100% and that i believe its far enough away from zero (in a suitably designed setup with the water being sprayed far enough back, and iats hot enough to start with) to make an appreciable difference to iats.

only actual numbers will make this argument go anywhere useful, and because no one is going to bother producing suitable apparatus we should just forget about it...

Re: Water Injection 2007
 

------- fist yourself, Fred.

Re: Water Injection 2007
 

okay so fred..... when you say the water droplets will be evaporated taking heat outta the air...... where the ---- do you think that heat goes? it goes into the water (water vapor at this point according to you) and continues to enter the engine, so your theory of intake AIR temperatures being reduced may actually have a slight reasoning, but that heat that the water pulled from the air is still entering the engine pre-combustion so therefore not making any ------ difference what so ever on the intake temperatures


also like JD said, the air is moving way to fast for it to efficiently evaporate water droplets. evaporation takes place most efficiently in ambient air (at least in weather, being a professional sailing coach, i tend to study weather a lot as well) so the air in a say 2.5" charge pipe is moving FAR to quickly for the droplets of water to have sufficient time to evaporate and do any cooling BEFORE the air the water was sprayed into hits the combustion chamber on an intake stroke

so yeah i can see what you're saying about how it may be possible to chage states and cause a cooling effect under ideal conditions like it being injected PRE-intercooler to get rid of the remaining heat thats just changed between matters


so i'll agree that the efficiency increase is somewhere between 0% and 100% but its far more like 0.00001%

Re: Water Injection 2007
 

So I recieved and installed my devils own injection kit. I am currently running a m2 nozzle and started spraying it at 15psi. I used one bottle of heet and the rest of the resevoir distilled water (1 gallon res. i think). There is a noticable seat of the pants difference once its hits 15psi I thought. So i dropped it to spray at 12psi, felt better from 12psi and up. Now im spraying at 10psi and up and can tell the difference. Definitely not 50whp but it feels alot better/smoother. Im going to step up to a m5 nozzle and see how it goes. I can also tell my intake manifold is much cooler, still hot but alot cooler. Im thinking with a m5 nozzle i maybe able to keep it cool. Generally it gets VERY VERY hot....

Re: Water Injection 2007
 

From what i've heard, iat decreases are just from the wet thermometer effect, as JD says. More fascinating to me is the heat of combustion that, instead of being lost into the head, is carried in the superheated steam out the exhaust, which has been observed to cause valve seat erosion in WI engines (along with a nice steam cleaned chamber). This extra exhaust mass should cause faster spool and lower boost threshold. I've seen one or two dyno graphs that support this idea, however they also show the falloff that occurs up top because the extra mass also serves to choke the housing in the higher rpms. It seems to me if you're heartset on chemical intercooling, you should pick an exhaust housing up on whatever turbo you were planning on getting, to get full benefit of this effect.

Re: Water Injection 2007
 

Sweet, all that heat was carried via the water directly into your combustion chamber. Not the best use of the water's cooling properties - I'd much rather have it cool the combustion chamber and nothing else. Congradulations.

Re: Water Injection 2007
 

Intake manifold could be cooler for other reasons, not just the water entering it factor. Only way to find out is add more water.....

Re: Water Injection 2007
 

I personally feel that misting water into your intake is pretty gay