Water injection

[Chevy454]

Any of you folks here run a water injection system on a boosted application? Is an alcohol/water mixture a *must*, or will a straight water solution do a suitable job? And what's needed to inject it? Could you plumb it like a fuel system with an additional set of injectors, or does it need to be further upstream, or...?

Trying to get a plan of action for our upcoming project, but new to this turbo stuff...

[kmcanally]

I not boosted but I have read that this guy has the system that you need....

www.snowperformance.net

[Blown353]

I run water injection, I bought the controller from Julio Don. His website is http://www.alkycontrol.com

It isn't the only option out there (there's also SMC, Aquamist, and others) but I have experience with Julio's unit and it's a well built and reliable piece.

A progressive controller is the way to go. You set the initial pump speed and pressure at which it turns on, then you set the ramp rate (how fast it increases pump speed as more boost comes in.) That way you can tailor the amount of water injected, rather than a single stage "on or off" system." For example, I have my controller starting with just a trickle of water at 3 psi of boost but at 15 psi of boost (my maximum) the pump voltage ramps up enough such that the pump runs just below the high-pressure cutout safety switch on the pump, and it delivers a LOT of water at that voltage. To adjust water volume delivery at the maximum safe pressure, I simply install larger nozzles. When the pump "bounces" off the high-pressure safety switch it pulses on and off and delivers water unevenly.

I'm using the controller in conjunction with a diaphragm pump from Northern Tool (about $60) that I re-adjusted the pressure limiting switch on to give about 140 psi. (The switch cuts the pump out at about 60 psi out of the box, and the pump will put out over 300 psi if you run it with the switch bypassed-- trust me!) The nozzles are filtered brass atomizing nozzles with integral filters from McMaster-Carr; I believe I'm running two M5 nozzles right now (that's 5 GPH per nozzle @ 60 psi.) The pump sucks through a fuel filter I found from K&N (clear plastic body with stainless mesh filter.)

One thing to keep in mind is that you will need solenoids if you install the nozzles under the throttle plates, as engine vacuum will suck water from the tank without them. If you install before the throttle plates, you don't need solenoids, but you'll still want to install the injection nozzles higher than the reservoir to prevent siphoning the tank dry. If the tank is higher than the nozzles, you'll need solenoids. I have my nozzles in the intake piping just after the supercharger and the tank mounted lower than the nozzles; this gets the solenoids out of the picture and makes the system simpler. Good solenoids rated for the pressure will run about $40 each.

There are REALLY fancy systems out there by Aquamist that have magnetically-coupled motor/pump combos and controllers with pressure-sensitive full feedback for clogged nozzles and signalling your ECU to revert to a "safer" map when the injection fails, but the system I pieced together is quite a bit cheaper and functions very well and has been reliable. Aquamist also has lower-end systems without feedback.

Water will pull out more heat from the intake charge than water/methanol or straight methanol, but the disadvantage is that it isn't combustible and you can't spray as much as a water/methanol or straight methanol mix. Too much water and you'll literally "drown" the spark out and kill the engine-- even at wide open throttle. Methanol will burn, so you can spray more before you run into problems. The disadvantage to running methanol is that it's corrosive to aluminum-- that means your intake, heads, etc.

I run straight water myself. I use distilled water to avoid hard water deposits / clogs in the pump, plumbing, and nozzles. The system has been reliable so far for just under 7000 miles. Just remember to fill the water tank from time to time! You can also put ice water or ice in the water tank.

NOTE: The "boost cooler" system posted above me uses the EXACT diaphram pump you can get from Northern Tool.

Troy

[Supra510]

I use the Aquamist system. I don't have the fancy computer controlled one, just a pump, pressure switch and nozzles. It was OE on a Ford Cosworth model in Europe I believe so the reliability should not be an issue. I have my pressure switch set to come on at 10 psi

I think whichever kit you get should be fine as long as it is from an established vendor. I use mine more as an extra safety feature than anything else. I've run 16 psi at Thunderhill in 105+ temps and had not detonation or cooling issues running pump gas. A benefit besides keeping the intake temp down is that it also helps the engine run cooler. Not scientific, but no one else that day was running much over 10 psi because after a lap or two the coolant temps started getting out of hand (and they had quality radiators).

Be careful if you are relying on the system to run big boost #'s that you keep the water resevoir full or you'll have issues.

I've run straight water and 50/50 water/alcohol. Didn't notice much of a difference either way, but I'm not running huge boost either.

Anthony
http://www.cardomain.com/ride/674663

[hotroddr]

Anybody put together their own system? Pics? I am going to be running a 12:1 compression motor on the street and will be experimenting with water/alcohol injection in order to get away with running pump gas.
The motor is a chevy 302 with domed pistons and vortec heads. Anyone have experience with vortec heads and high compression?

[68RallySport]

I use the SMC kit on my TTA. I run a te-44 turbo and i couldnt get more then 15psi out of the turbo without detonation. I installed the smc kit and used straight denatured alcohol bought at home depot, and now i run 24psi with zero knock!

[GetMore]

Something to think about: (and to be verified or disproved) when the compression and chamber temps get high enough you can separate the oxygen and the hydrogen and get even more of a boost.
The original applications used straight water, but alcohol was mixed in to prevent freezing.

[Y-TRY]

Anyone done back-to-back dyno comparisons, with/without the sprayer on?

I know all of the theories, but what about a dyno chart of real world advantages?

[Fuelie Fan]

I'm about 95% confident that the oxygen in water won't contribute to combustion, whereas the alcohol absolutely could. I'll see if I can find the proof

[Fuelie Fan]

PS: if you knew ALL the theories, then you'd probably have a pretty good grasp of all the real-world advantages, wouldn't you? Considering that this subject has had umpteen million papers written about since (and even before) it became a popular subject on WWII aircraft, there's a lot of theories concerning the subject.

To paraphrase a smart man on another site: H20 injection provides a power benefit IF and ONLY IF the compression ratio is too high for available fuels, and it provides this power increase almost entirely by allowing the operator to return the spark advance closer to MBT as opposed to having to retard the timing. The water is an anti-detonation device, it slows the early phase of combustion. Other "power increases" due to charge cooling and so forth are negligible (it's cooling the air, but also displacing it with steam that doesn't burn).

[camcojb]

Agree with the above. It absolutely works, but only if you tune for it. If you do not run more timing or boost to take advantage of the extra anti-detonation benefits you will notice little if any benefit. It was worth over 50 rwhp on my Lightning due to the extra boost/timing I could run on pump gas. I do not do a forced induction pump gas build without it.

Jody

[speedster]

Hey Jody -
What type of system(s) do you run?
Are you putting one on the new car ?

[camcojb]

Hey Jody -
What type of system(s) do you run?
Are you putting one on the new car ?

Absolutely, the twin turbo GTO has one. This one is from http://www.devilsownonline.com/alcohol/

I have used SMC, Snow Performance, and a couple others, all worked equally well in my opinion. The Devils Own is less money and has great reviews on the LS boards so I'm going to try it. I tried to get an AlkyControl unit like Troy has, but couldn't get Julio to answer the phone!

Jody

[speedster]

Thanks Jody.
Tom (Nelson) kept pushing me to add one, but I didn't think it was a big deal. Other than the stuff he showed me, I didn't know anyone ws using these. Maybe have to rethink this one.
Do you have a tank mounted in the trunk or how big a reservoir do you need for these ?
TIA

[rocket468]

I hope you enjoy it jody. Rember to turn the adjusting screw on the pump 7-8 turns. I can't remember if i told you to do that.
Bruce most people use ther factory washer tanks. Some people also add a tank 2.5q to 4q is the norm which should last you from fill up to fill with the 4q getting you every other fill up. Alot of it also has to do with how you drive. Turbo diesel guys go with 6 gallon tanks because they cruise in boost. If you have any questions ask away and I will try to help.

[camcojb]

I hope you enjoy it jody. Rember to turn the adjusting screw on the pump 7-8 turns. I can't remember if i told you to do that.
Bruce most people use ther factory washer tanks. Some people also add a tank 2.5q to 4q is the norm which should last you from fill up to fill with the 4q getting you every other fill up. Alot of it also has to do with how you drive. Turbo diesel guys go with 6 gallon tanks because they cruise in boost. If you have any questions ask away and I will try to help.

Thanks for the advice, I didn't hear that.

Jody

[camcojb]

Thanks Jody.
Tom (Nelson) kept pushing me to add one, but I didn't think it was a big deal. Other than the stuff he showed me, I didn't know anyone ws using these. Maybe have to rethink this one.
Do you have a tank mounted in the trunk or how big a reservoir do you need for these ?
TIA

You should seriously consider that, especially on 91 octane if that's what you have. I ran mine from my windshield washer reservoir, about 1 gallon. Lasted 3-4 tanks of gas, but I don't "drive it like you stole it"!!

Jody

[speedster]

Thanks for the info rocket and Jody-

It looks like I will end up ordering one from you rocket.
Where in the inlet stream is the most effective place to put the injector nozzle ? The intake is sheetmetal EFI.

Stole it ? Naw, i just temporarily "borrowed" it ...

[Y-TRY]

So, Fuelie Fan, your answer would be "No, I don't have any back-to-back tests showing the theories actually in practice for this type of application."

I know the why's and how's they apparently work, but I'm a tangible, graph, kind of guy. That is all. I'd just be curious to see one graph laid over another. You'd have to take Combo A to it's max boost/timing on the fringe of detonation, then add the injection to Combo B and tune it to it's max and see what you come up with. It'd be a cool test. I remember a Mustang Mag doing a non-intercooled vs. air/air vs. air/water test in a similar way.

I've considered one for mine, too. Any pitfalls unique for a carb application?

[Blown353]

Good to see yet another vendor (Devil's Own) is also using the Northen Tool/Shurflo pump... and better yet starting with the higher pressure unit.

I like their controller. My unit from Julio works good but the turn on and initial adjustments are in a box seperate from the main controller; the Devils Own box has everything convieniently located on the main controller.

It's best to adjust the pressure switches on the pump to whatever your lines and fittings will accomodate safely. I have my switch adjusted to cut the pump at 140 psi, as my fittings and hose are rated to 200psi. My pump pegged a 300psi gauge shortly before blowing up the hose when I totally bypassed the pressure switch-- so don't crank it up too high or bypass it entirely!

The usage of quick-connect "Legris" connectors and high pressure tubing instead of the more commonly used rubber hose and barb fittings seems eerily similar to my setup. I used nylon line and legris connectors on my car well over 2 years ago for all my vacuum lines and water injection system, and at that time I hadn't seen any other setup on the market or DIY-setup using the stuff. Not ragging on the kit at all at all (actually, it's a compliment)-- the plastic lines and legris connectors are clean looking, simple, reliable, and trick. Very easy to connect and disconnect.

Y-Try, no pitfalls to a carb application. I first built my DIY system back when I had the carb; back then it was a 2-stage pressure switch and solenoid controlled setup. The nozzles were in the carb hat. I've now gone to a progressive controller and like it much better; much more control of the spray and a much more consistant spray.

As far as nozzle placement, ideally you want it early in the intake system so the water "lingers" in the intake charge long enough for the water to vaporize and absorb heat from the intake charge. My nozzles are located just after the supercharger discharge. It's also simpler to locate the nozzles prior to the intake, as if you put the nozzles in the intake (exposing them to vacuum) you'll need to add solenoids to the lines to prevent engine vacuum from sucking the tank dry during cruise conditions. If you put the nozzles before the carb/throttle body they won't see vacuum and thus you eliminate the need for solenoids.

Another thing I suggest is you add a pre-pump filter; should you get some junk in the tank it will keep the pump clean and also keep you from having to remove and clean sediment off the filters on the mister nozzles.

One last tip: mount the water tank above the pump to gravity-feed the pump, but install the nozzles higher than the water tank... otherwise there is the possibility that the system can gravity feed with the engine off, dumping water into the intake, and possibly hydrolocking the engine the next time you start it.

Troy