Water Injection - from the chemical perspective

[GMCfourX4]

http://not2fast.wryday.com/thermo/water_injection/water_chemistry.txt

This was written specifically about gas engines, but has some interesting info (some of which is slightly over my head... its been a while since I've taken chemistry and physics...) but I'd like to hear input from anyone who does understand it well, and, ideally, some input on how this applies to our trucks.
I've always felt (based on the SOTP meter) that humidity kills the performance of my truck, my truck seems to lose a lot of power on humid days. My SOTP meter has, however, proven to be inaccurate before, and my truck is presently non-intercooled. I was hoping someone in the know could maybe shed some light on water injection as it pertains to our 6.5s, and maybe suggest what its actually worth in terms of performance, balanced with the need to keep another tank full (not to mention that you have to put something in there to keep it from freezing, and you'd probably be well advised to use distilled water to keep other "crap" out of your motor). Any thoughts?

-Chris

[DA BIG ONE]

Originally posted by GMCfourX4:
http://not2fast.wryday.com/thermo/water_injection/water_chemistry.txt

This was written specifically about gas engines, but has some interesting info (some of which is slightly over my head... its been a while since I've taken chemistry and physics...) but I'd like to hear input from anyone who does understand it well, and, ideally, some input on how this applies to our trucks.
I've always felt (based on the SOTP meter) that humidity kills the performance of my truck, my truck seems to lose a lot of power on humid days. My SOTP meter has, however, proven to be inaccurate before, and my truck is presently non-intercooled. I was hoping someone in the know could maybe shed some light on water injection as it pertains to our 6.5s, and maybe suggest what its actually worth in terms of performance, balanced with the need to keep another tank full (not to mention that you have to put something in there to keep it from freezing, and you'd probably be well advised to use distilled water to keep other "crap" out of your motor). Any thoughts?

-Chris I have a water injection system for Heath will be installing it soon. I have the IC that mounts between the rails under the front bumper, not the best but better than nothing.

HP gains seem to be limited to the 35 to 40 +- on highly modified setups, less on stock motors, but the reduction in thermal stress is best part of the system!

I do get a slight pressure drop across the IC and have my boost right at what I believe is the limit of the compressor GM-8.

First issue that presents itself is that the water injector has to be installed after the IC so water does puddle inside IC.

Next, will the nozzle and pressure be acceptable to use after IC? Pressure may be ok, but nozzle must be adjusted to atomize water to fine mist so it absorbs whatever heat there is after IC, and not just pours in to take doing little or nothing for cooling.

Then one must tinker with water injector on and off pressure, so water can do its job and not be wasted.

I can run w/o water injection safely, but consider it extending the margin of safety.

[ 03-04-2005, 05:35 PM: Message edited by: DA BIG ONE ]

[JoeyD]

I have Bills water kit and it should be installed at the turbo, mine is drilled and taped into the housing. I think the effects of it after the intercooler will not be as good. The air is already cool before the water hits it. I think there are kits out there designed to do this with greater water pressure and a finer nozzle to mist it in. Snow performance i think makes a kit that the Dodge guys were raving about.

[DA BIG ONE]

Originally posted by Joey D:
I have Bills water kit and it should be installed at the turbo, mine is drilled and taped into the housing. I think the effects of it after the intercooler will not be as good. The air is already cool before the water hits it. I think there are kits out there designed to do this with greater water pressure and a finer nozzle to mist it in. Snow performance i think makes a kit that the Dodge guys were raving about. Point well taken! But I have not seen a really good IC setup for our 6.5TD because of space issues, thus there is lots of unwanted heat stiil in the aircharge after the IC.

The turbos on our GMs start to superheat the charge after say 15lbs +-, I am sure others can chime in on this too.

On the highway any IC is always much more efficient, but around town, or during slow heavy pulls up hill it is not so adding water injection helps. At speed the extra oxygen introduced by a fine high pressure mist into motor helps too.

Main thing is to avoid droplets of water, cause they do little or nothing for cooling the charge.

[turbovair]

Humid air has less oxygen available per cubic foot than dry air. Water vapor takes up valuable space normally occupied by O2.If you've ever excersized hard on a humid day you know what I mean.Jet engines also produce less thrust when fed humid air(with higher EGT).Although water injection was used on early turbojets(J-57)to increase thrust, additional fuel was added at the same time.The prime benefit was keeping EGT within reasonable limits while providing some additional O2 to aid combustion.Even with water injection, the engines generally smoked a lot(black) as a byproduct of additional jet fuel being added during "wet takeoff".