J. Davis said that I should post my findings since i'm build a ghetto/self-made water injection kit. I'm going to first ----- the original thread where this info comes from.

Water Injection Info on CarolinaHondas.com

But for you lazy people I summirize it a bit. There are a plethora of good links for those of you interested in W/I as a means to cool intake temps and control detonation. There are a few ways you can use water your forced induction system. I'd like to note also most mix in a 50/50 amount of water-alcohol, this bumps the ocatane rating when directed directly into the engine or adds a better level of evaporation/heat dissapation when used externally.

The I/C Sprayer Method.
The first and most simplistic is to just spray it on the outside of the I/C. Now this isn't really considered a form of "water injection", but it does cool the I/C down enough on hot days for a marginal gain in power. A simple toggle switch on the dash or if you're lazy and inventive a WOT switch could be used as well.

A better method, would be the *NOS* brand I/C sprayer. I've also seen custom CO2 I/C sprayer setups people have devised, cheaper and easier to fill than N20 in most cases. I've honestly thought of carring a Co2 based fire extingisher to the track to hit the I/C with before each run...of course that would only be feasable at a track, not so much in real life.

The Pre-Turbo method.
Where you base the sprayer nozzel at the turbo inlet. A mister nozzel or streaming jet can both be used, as the spinning turbo blades will atomize the water fairly well. This will usually cool the intake temp down and help with I/C effiecientcy, however this can be very abusive to the blades of your turbo. While not as simplistic as the sprayer method, it's still only marginally effiective at adding real power or controlling detonation.

Post-Turbo Method.
This is the preffered method, IMO. This system is more complex then the others due to the fact that you must use a pump and nozzle that can properly atomize the water with a positive intake pressure working against it. Thus the system usually operates on very high working pressures, generally in order of 80-100psi. With that in mind, more thought must be given to water flow, and how to control is precisely. Nozzel placement is somewhere in the order of 3"~6" from the throttle body. However I have seen/heard of setups that use a direct port method, much like nitrous kits, this provides for a superior distribution into each cylinder. Aquamist, Spearco, ect kits are of this type. The best W/I "kits", most will agree, are made by Aquamist. Their cheapest kit will run your about $400 tho...

Here is a rough sketch of my planned water injection setup. I have 75% of the parts ready to do this. A legend is at the bottom, along with some great links on how you can build your own W/I setup. Feel free to copy my idea tho, as I think it is a very complete setup. My current running total is about $80, with at max another $50 to spend.



A - 3/8" MIP -> 1/4" Barb
B - 1/4" MIP -> 1/8" Barb
C - 3/8" MIP -> 1/4" FIP adapter
D - Inline Filter
E - Check Valve
F - 12v Solenoid for ON/OFF flow control
G - 1/8" Tee
H - .7mm Aquamist nozzle
I - 1/4" FIP Tee
J - 0-200psi guage
K - 1/4" ball valve
L - 30 Amp relay
M - Hobbs adj. pressure switch
N - 1/4" MIP union

THE best page on water injection I found thus far, it's on GN. Very detailed

W/I on a Merkur, fairly detailed w/ temp comparison

SAAB page, w/ decent pics and part listing

A fairly boss calculator page, complete with W/I nozzel sizing

 

so your not running an intercooler? just the water injection unit? i was under the impression that water into the engine was a bad thing?? i guess if its atomized it doesnt matter?

 

Certain amounts won't hurt it. If you plunge your intake in a gallon of water, yes. If you spray a fine mist into it, no.

BTW nice diagram man.
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No I am running an intercooler already. I want to use water injection as a means to run 20+ psi on pump gas. Of course this is on a built engine with a t3/t4 turbo. The cost of my W/I kit will prolly be less than 2~3 tankfuls of "race gas". Plus water/alky is easy to find and cheap if I run out. The cheap-*** blue windsheild fluid is a 50/50 water/alky mix.,,

 

so you'll be using blue water ( the 88 cent wiper fuild) for your water injection....it doesnt sound like a bad idea...but probably not worth it running less than 10 psi?

 

wonder if this would help out an N/A at the track on a hot day.

 

That is correct, you prolly won't see much reason for using it under 10psi. The only way I would use it under 10psi, is if I was tuning the setup to be W/I dependent. This has it's merits and pitfalls. Mostly that if you tune your setup to be W/I dependent, you'll be able to run more agressive timing which would yield you more power. However if you run out of water/alky while boosting around the street, you're gonna run into problems. You won't be able to boost until you refill the W/I.

Actually, if you're a really nasty N/A man the W/I could help out. If you're running moderately high compression, you could run water/alky as a way to contain detonation or "spark knock". If you're running enough compression ration to need gas higher than 93 octane, W/I could help you out. It would also allow you to running more spark advance, or more agressive ECU programming.