I think there needs to be a seperate thread on this, possibly a sticky. also I have been reading up on water injection, and uperently it does wonders for people. Please feel free to post your thought about water injection. Any experience or knowledge is greatly apreciated.

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1. Water injection increases the mass of air/fuel mixture entering the cylinders, because it cools the hot air from the turbo's compressor. As the water droplets hit the compressor wheel going 100,000 rpm or so, a mist of amazingly small droplets is formed. These have such an incredibly large surface area compared to their volume that they evaporate (change to vapor) almost instantly, absorbing a tremendous amount of heat from the air-fuel mixture just before it is compressed and lit. The cooler mixture is denser, so for a given boost pressure, there will be more fuel and oxygen in the cylinder when the intake valve closes.



2. Water injection allows a higher intake manifold pressure before the detonation limit. The torque your engine produces is closely related to manifold pressure. Double the pressure, and at any given RPM, power will be approximately double. This applies only when the pressure is measured as "absolute" rather than the common "gauge" pressure. There are a number of ways to define absolute pressure, the most appropriate for turbos being "Bar". On the Bar scale, 0 is a vacuum, 1 is standard sea-level air pressure, and so on. A naturally-aspirated (non-supercharged or turbocharged) 510 will almost get 1 Bar at the peek torque RPM, while a turbocharged 510 can often exceed 2 Bars with water injection. This corresponds to about 15 PSI boost. Joe Keller of Whittier, CA, has exceeded 3 bars on his very trick L16. This represents about the limit for a single-stage turbo, and required 6:1 compression, aviation gas, and water injection.



By Member David Lewis

(www.510again.com)



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As many of you know, water injection has been used for many years to help suppress detonation on high performance internal combustion engines. It is usually possible to run higher compression ratios, more boost pressure, and further advanced ignition timing on an engine with water injection. With everything else working properly, this should result in more power. Water injection works to increase the effective octane rating of the mixture entering the cylinders. This is accomplished through charge air cooling (water vaporization requires a tremendous amount of energy), and through the "slowing" effect the water vapor has on the combustion process. This helps prevent the uncontrolled combustion that can destroy an engine.



Let me give you a little history behind how I finally arrived at my latest water injection design. About 2 years ago, I decided to experiment with water injection after reading about it. I was fascinated with what some people had done in the past. For example, I believe it was back in the 60's when a guy ran a "low tech" Corvair with dual stock Rajay turbos, propane fuel, and water injection at Bonneville and reached 176 MPH. His turbocharged motor was said to produce over 450HP...with NO intercoolers. The simplicity and potential of water injection really appealed to me.







CHARGE AIR TEMPERATURE DATA



TEMP(F) W/O H20.................TEMP(F) W/H20



316.9....................................170.4

326.0....................................168.9

324.3....................................168.9

322.3....................................170.8

317.6....................................185.9

317.0....................................150.7

320.8....................................173.8

320.0....................................170.9



I was very surprised at the tremendous temperature drop caused by the water injection. It dropped the temperature 150F!! This is more than the average temperature drop in my air/water IC system! H20 injection is a very economical intercooling solution. Total cost of my system was probably around $80 or so. This is a real bargain considering the tremendous "intercooling" effect of the water.



Unfortunately, the laws of thermodynamics will not permit the 150F temp drop for the H20 injection and 146F temp drop through the IC to collectively add. Too bad...air temp drop would be near 300F...with charge air temp approaching 0F...80 F below ambient air temperature! Brrrrrrrrrr! The actual charge air temp drop for the water injection and intercooling combined is a little over 190F.



Some brief parting notes, it is very important to have a solid ignition system to enable the spark plugs to fire in the water vapor filled mixture. I replaced cap, rotor, plug wires, & spark plugs. I gapped the plugs a little smaller (around .028) to make it easier for the spark to jump during high boost conditions. Tuning up the ignition system made a noticeable improvement in power delivery - the engine accelerated more smoothly.



Water injection...proof that simple ideas can be very effective!





(http://home.ccci.org/Key_Information...rInjection.htm)





Some of the mods on that car

(visit http://home.ccci.org/Key_Information/MerkurPage.htm for more info):



Ported Big Valve Cylinder Head

Turbonetics T3/T04E Hybrid Turbo

SuperCoupe Air/Air Intercooler Installation

Big 60mm Throttle Body

Ported Intake & Exhaust Manifolds

K&N Cone Filter in cold air plenum

Hi Flow Exhaust - 3" Mandrel Bent DP, 3" CAT, Magna Flow Muffler (3" IN, DUAL 2.5" OUT)

Boost set at 20psi

Bosch Bypass Valve

45pph flow matched Bosch injectors

Walbro Hi-Pressure 255lph Fuel Pump

EEC Tuner





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I must say this is quite impressive. Did I mention this cost $80!! The only "expensive" components were the pump and the nozle, both at under 80$. For this kind of result, this really a worthy upgrade.



There are poepe on http://www.homemadeturbo.com who run at over 1000+ hp and are VERY pleased with water injection.



There is also has been experementation with injecting water directly in to the turbo. Test show that as long as the water is atomized in to a fine mist before it enters the turbo, the blades take no wear and preformance soars.



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Wonderful Sticky on homemadeturbo.com



http://www.homemadeturbo.com/forum/i...d=4257;start=0



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some great links:



http://home.ccci.org/Key_Information...rInjection.htm



http://www.dawesdevices.com/howto.html



http://www.510again.com/articles/wat.../watering.html

Do not spay directly in to turbo if you are using water. It will make the housing and parts rust. That ofcoarse IF the water doesnt evaporate imidiatly which it should normaly but better safe then sorry. A guy form aquamist (they make water injection kits) said that it is better not to spray in to the turbo itself. He said the intake mani or the charge pipes right before the t-body ar ethe most ideal spots to mount the water injector.

a point for all that worry about keep refilling the water tank:



"I am using a Saab intercooler as a reservoir, and managed to thread a screw into one of the drain plugs on the bottom, using that to feed to my pump.



I am not sure how much of it is emptying, but I do know that it doesn't really need to be filled up except every 2 tanks of gas or so. I usually top it off every time I put gas in the car. But I have drove over 600 miles without having pinging, this is also with the boost sensor set to activate at 1 psi."



-Chacko

http://www.homemadeturbo.com

another thing is with water injection you can take out your intercooler, thus cutting down the lag!!

any questions/comments/advice/tips are welcome, post away ^^

Have a look around the main Aquamist (makers of water injection kits). There is plenty of good information on here, sadly not much relating to rotarys, but I am looking to change that as I will be speaking to him very soon about upgrading my install. https://www.nopistons.com/forums/pub...IR#>/smile.png



Dan

awsome, alas! we will have actual data on here on how well it does. From what I have learned water injection does more for rotaries then piston engines.

someone in another thread asked if this requires a seperate tank for water. Yes and no. You can use your windshield wash fluid tank for this or mount a seperate one.



I was thinking and realized:



1. with water injection there is no need for the intercooler



2. if no need for intercooler the why not remove it, and cut down the lag



3. !IDEA! why not KEEP the intercooler, but use it as a container for water (or whatever your mixture is). Basicaly like a radiator. Kepp the water that will be injected nice and cool. Hence helping wi to be mor effective.

i dont think just using waterinjection will illevate the need for an intercooler. Water injection operates under boost. The air is still going to be hot without the water injection!



What are your goals for the car?? Are you going to drive it on the street?

WFT?????! I am lost. What are you trying to say? ofcoarse it will be hot without water injection. Thats why you get water injection, to cool off the air. And yes it does eliminate the need for the intercooler. A few people on http://www.homemadeturbo.com have done water injection and said that there is no need for the intercooler.

You'll still need and intercooler. Waterinjection is good for two main reasons. It will allow you to run more boost safely or more advanced timining safely. This is of course a result of the intake charge temps being reduced by the atomized water. And of course it would help improve the overall reliability of the car if you left the boost and timing the same as it was before the H20, but wouldn't effect horsepower.

Those cars are also piston powered...Rotary's are finicky...we need all the cool air we can get. I'd run an intercooler only if I had to choose between the two.

I have a huge write up on this thead:



http://www.rx7club.com/forum/showthread.ph...water+injection





IN a nutshell, I find that my air temps are from 20-32C on a hot day with the WI and it pulls hard as hell even when its 100F outside. I have one nozzle in my elbow pointing 90 degrees down the pipe (toward the hot air) and one in my intercooler end tank. they come on at 8 psi. I have a 2 gallon water tank that lasts a long time. Cost for a single stage setup is about $140, a dual stage like mine runs about $180 for the parts.



Injector and selenoid 1

http://members.aol.com/zerobanger/injector.jpg



A view of both the injectors, the other is in the endtank of the IC, you cant see but the other selenoid is mounted behind the IC:



http://members.aol.com/zerobanger/dual.jpg





pic of the water tank and the pump:



http://members.aol.com/zerobanger/bottle.jpg





considering it does the following:



1) steam cleans your engine, sparkplugs and exhaust eliminating carbon deposits.



2) gives sub ambient air temps, therefore advancing your timing.



3) allows you to run more boost than you could without or gives you a huge safety cushion with your current set up



4) car no longer feels like a dog on a hot day.



5) no more heatsoaking or power loss between 1/4 mile or dyno runs. Ok, to clarify you are sitting in traffic for long time in hot weather...your intake sensor will get heat soaked, but as soon as your boost the air will be cooled before it enters the combustion chamber which means that while heatsoak technically exists, it is not relevant because the air is cooled before reaching the engine.



6) my car doesn't backfire like it used to in hot weather. when my intake temps get hot my car back fires upon deceleration, no more.



7) I Could run 87 octain and/or remove my IC and run only water injection.



8) in my case, my car is set up to have enough fuel for 16 psi (without the WI) but my IC (BLITZ SMIC) can only support about 14. I only run 12 cause if I get a bad tank of gas, i'll pop my engine. Now I have no fears running 14 psi on pump gas on the street with the water turned on. the chances of the Water Injection malfunctioning and having a bad tank of gas at the same time are slim to none.



9) octain of the gas is increased, due to the cooling effect of the water/alcohol or just water being injected.



10) I wanted a 10th advantage but I cant think of one right now.







Disadvantages:

1) hydrolock. If its set up wrong you could have water going into the engine at idle or when the car is off, killing the engine. not an issue when done right.



2) gas mileage. I would guess that since the timing will be advanced you use more fuel, but thats just a guess.



3) problems are difficult to diagnose. Had some issues early on and took me 3 weeks to figure them out. been running solid for a month no problems daily driving.



4) you have to maintain the water tank.

exactly, water injection is the way to go https://www.nopistons.com/forums/pub...#>/BURNOUT.gif

talked some people running water injection, and they said you can run a lower octane fuel. Which i understand why. But they also said you can run a lot leaner mixture.



But aren't we still trying to aim for 14.7 stoich? (or slightly richer)

I say water injection is good. But you dont need it inless you want to boost high 15+ psi. I woudlent mind testing it out once i get enough money that i dont care if i blow my engine up. Someone go get dragon he prob has some insite on this.

the only way this can blow up your engine is if it hydrolocks. BUT, autospeed.com came up with a module that varies the flow of a water injection so that it rises with engine load.



http://www.autospeed.com/A_1539/cms/article.html



actually aquamist products feature everything from simple modules that regulate the amount of water injected by sencing boost preasure to ecu's that you can proggram and map it anyway you like.

the thing is, you dont inject at all times. It wiould still be useful to have a intercooler for thoes times off boost. The air has to pass through the hot turbo even when you are not boosting. Lag isnt going to be increased that much by having an intercooler.

to clear things up...someone said you dont need it unless you boost 15 PSI...I blew my engine at 12 PSI on the dyno. Water injection would have saved me 6400 for my rebuild and other stuff I got done.



As far as having a 14:7, mine is 12:1 and i'm happy with that. Tuning for a 14:7 would work, but you better never run out of water or malfunction with the WI.



As far as hydrolock, you will never hydrolock as long as you only spray water when you are boosting and make sure the water is a fine mist (EG you need a high psi pump).



For example I'll give you a quick idea how to figure out the nozzle size. You can go with an expensive aquamist that varies the output based on the fuel, but remember its $$$$ to install and very expensive to buy (but worth if if you have the cash) or you can do this..



My nozzle is .77 @ 60 PSI and the other is 3.87 @ 60, so im around 4.65 Gallons per hour. My fuel at 100 pct duty cycle is 3500 CC ( 2 X 1200 and 2 X 850=3500). Here is the chart that gives my totals, the duty is the duty cycle on the power FC, the pct is the percent of water to fuel. you want to be between 10 and 20 pct. As you can see, I never have too much water. I plan to get a 100 psi switch for my pump, that will raise my nozzles to a total of 6 GPH and put me in an even better water distribution. Just don't put too large of a nozzle or your car will drown out and the ignition will break up.



duty pct duty pct

42 19.73% 69 12.01%

47 17.63% 72 11.51%

49 16.91% 75 11.05%

51 16.25% 78 10.62%

54 15.34% 81 10.23%

57 14.54% 85 9.75%

62 13.36% 87 9.52%

65 12.75% 90 9.21%

yeah thats a good point. I though taking out the ic would cut alot onthe lag, but if not then yeah, its definetly worth keeping.



As far as running out of water, unlese you are running something like 30psi and spraying in insane amounts then you shouldnt worry. I knwo people who run at 20+ psi and a 2 gallon tank lasts them 3 gas tanks. And with about between 10 and 17 mpg. At this point water is nto a big problem. You run out of gas alot sooner, and water unlike gas can be obtained at little cost, we are talking cents to no cost.

I want to purchase a aquamist kit this winter, therefore I don't have to do the FMIC till later on. I've heard wonderful things about it, and we all know how much harder are cars pull on a cool day, just think of that all the tim https://www.nopistons.com/forums/pub...IR#>/smile.png I plan on having the WI coming on at 8psi.... And I will ofcourse still use my IC, I think thats just a bad idea... I never see ppl running w/o an IC unless they are using a meth mix..

"But aren't we still trying to aim for 14.7 stoich? (or slightly richer)"





14.7 is way too rich.....high 10's and 11's are the best for performance. I was told 10.8 is the best in rotary

I have heard that water can shatter the apex seals if you're not carefull with the set up. It's like the ATF treatment going wrong and breaking things, not common.



The other issue is build up of minerals in the water, I've seen this happen on a ford truck that was outfittied with injection. Use distilled water.



Water injection should NEVER be used in place of good tuning. It'll only delay the end https://www.nopistons.com/forums/pub...#>/biggrin.png

Zerobanger, I can't tell from looking at the picture. Where did you stash the tank and pump?

spare tire well.

14.7 is stoic...closer to lean than rich. I idle at appx 13.7 a/f and anything below boost...I'm at 13.7 to 12.7 a/f. When I get into boost, anything above .6 boost, I'm already at 11.2 and go to 11.0 above that. When I go even higher boost I may just go 10.9 to be on the safe side(1.3 kilos)

14.7 is stoic...closer to lean than rich. I idle at appx 13.7 a/f and anything below boost...I'm at 13.7 to 12.7 a/f. When I get into boost, anything above .6 boost, I'm already at 11.2 and go to 11.0 above that. When I go even higher boost I may just go 10.9 to be on the safe side(1.3 kilos) [/quote]

*feels stupid* https://www.nopistons.com/forums/pub..._DIR#>/sad.png



what are you guys talking about?

air/fuel ratios.

14.7 is stoic...closer to lean than rich. I idle at appx 13.7 a/f and anything below boost...I'm at 13.7 to 12.7 a/f. When I get into boost, anything above .6 boost, I'm already at 11.2 and go to 11.0 above that. When I go even higher boost I may just go 10.9 to be on the safe side(1.3 kilos) [/quote]

*feels stupid* https://www.nopistons.com/forums/pub..._DIR#>/sad.png



what are you guys talking about? [/quote]

14.7 a/f ratio is stoic(stociometry if memory serves me)...basically in chemistry a one for one burn(it's been about 10 years so forgive me on this one guys)so that when gasoline mixes with air and combustes, you'll get CO2 and H20 at the end of the tail pipe. Problem with running stoic is that you'll run very hot egt. The higher the number, the leaner the mixture. The lower the number, the richer the mixture. So rotary's under boost tend to like to have an 11.2 a/f...richer than stoic

11 air to 2 octaine right

lol...no. 11.2 : 1

why did you have a 4 post conversation with urself ....when u were just copy and pasting?

well I posted the main part but then I found more stuff, and then some more, and then I wanted to comment on something ^^

theres a button called EDIT

Chill out, you could have just pm'd him. He is here to learn like everyone else.

lmfao...Freestyle's bitching about someone who's contributing useful information to the forum. https://www.nopistons.com/forums/pub...1047683561.gif

I haven't read the first page, but here is some information that should be helpful to some of you...



11-11.2:1 is a relatively safe a/f ratio, peak power is somewhere around 11.7-12:1 or so, but you GREATLY increase the chance of blowing your **** up for a measly 10-20hp if you run toward the lean side. The reason a rotary needs to run rich is actually for two reasons.



# 1. Poor atomization of fuel due to the design of the rotary engine and the fact that the combustion chamber where the air and fuel needs to be when it ignites is moving. The atomized fuel is burnt, but their is some left over that isn't atomized that gets kick out with the exhaust causing a rich reading on the O2 sensor.



# 2. The extra fuel is also needed to cool the rotor. This helps eliminate hot spots that can cause predetonation.



if you run too lean you will get very hot ex temp, however if you run too rich you will also get very hot ex temps due to the left over fuel burning in the ex manifold. The way we used to tune prior to getting our kick ass wide bands was to tune rich to start and watch the ex temps drop as we took away fuel until the ex temp wouldn't go any lower. If you continued to take away fuel it would start to rise again and you knew you were getting too lean.



Here is what air/fuel ration is. I.e. Stoic. Say you have 1 gram of fuel, in order to burn all that fuel efficiently you will need a mass of 14.7 grams of air for it to oxidize with during the combustion process. This gives you the 14.7:1 ratio. When you run a richer a/f ratio you are basically giving the engine more fuel than the air to be had can burn. This extra fuel evaporates in the engine and removes heat. Another benefit from this and also from the water injection is that when a fluid evaporates taking away heat it also expands and will create more tork and can also aid the spooling a turbo faster since the exhaust pressure will be increased and be more dense.

Solution:



Run water injection and go home happy https://www.nopistons.com/forums/pub...IR#>/smile.png

Just found this.. https://www.nopistons.com/forums/pub...#>/biggrin.png http://www.zaxjax.com/Air%20Fuel%20Ratio%2...cal%20Paper.pdf This will help you understand what a/f ratio is

Does anyone have any experience on what happens to EGTs in the presence of water injection? Dragon's post implies that they are considerably lower which is what you'd expect.



But I'm not sure that this is good for spooling a turbo. I've heard many times how the drive for the turbine comes from both the difference in pressure and temperature accross it, not the pressure difference only. On piston engines running antilag the pre-turbo EGT's are huge.



I have no personal experience with this, but I'm just trying to consider any downsides to water injection.