I was wondering what were the benefits and negatives about water injection... should i even get it for my FD.

 

this thread might help ^^

http://www.nopistons.com/forums/inde...howtopic=25011

 

Pros: Will drop intake temps by a hell of a lot.
Cons: Without something like the Apexi/Wolf/Haltech type ECU's you could loose power. This however is not certain.

Dan

 

where would be the most efficient place to install the water injectors??????????

 

Between 5-10 inches before the throttle body.

Dan

 

According to my Aquamist manual:

Road cars..."For most road car installations the best result will be achieved by positioning the nozzle close to the upstream of the throttle body."

Highly modified road/rally car..."Cars with a power increase at up to 100% should consider installing the water jet at the exit chamber of the charge air intercooler."

Racing cars..."Water should be introduced as early as possible, the obvious place being on the up-stream of the intercooler.

Hope that helps

 

I put one in my end tank (the exit end tank) of my intercooler and the other in the stock elbow. Its actually about 6-7 inches from the entrance to the manifold, but its pointing downstream toward the flow of air for even better atomization.

 

If you are running boost water injection will allow you to increase your manifold pressure without getting detonation as soon, so if you aren't running a turbo, the water injection will probably cost you some power as the 7s don't have enough static compression to cause detonation.

 

you can also run alcohol injection, i dont know for a rotary, but its working well on nissan's rb20. doesnt lower your intake air temp but will indeed allow you to run more boost, more safely.
you could also run both, thats what i'd do if i had a turbo engine

 

you can run a 50/50 mix of water and methonal. methonal is 113 octane and cools alot. this mix can give you anywhere from 60-100 hp tuned right and keeps detonation down and alows more boost. the methonal being a fuel makes up for the lack of fuel when the air charge gets denser. thats why you can make more power. strait methonal running drag cars don't use intercoolers because the charge of air and fuel is cool enough.it should be injected before the throotle body, and when it comes on the car should not bog or you have to much being injected. I have a way of making a home made kit so just pm me

 

http://www.turbomirage.com/water5.html
this is how to make a home made kit.

 

my question is, lets say your car is tunned for whatever is on it. You put on water injection but dont want it always be on, only when you hit lets say above 4000rpm. So you cant tune your car for the wi because it wont always be on. My question is, taking these in to consideration:

-if methanol is used for fuel you need 2x then gas.
-when water injectiuon goes on it leans the car out

but if you have a 1:2 ratio of water to methanol then when water leans your engine out the 2 parts of methanol negate that effect. (2 because it takes twice the amount then when using gas)

so when you spray a 1:2 ratio of water and methanol it will even itself out thus no problems.

makes sence or am I an idiot and missed it?

 

thanks for the info, probably have my car tuned with water injection on a dyno and see how much boost i can get safely without race fuel on the gt40 were going to experiment with.... thnks

 

im trying to decipher this, not sure your question. You can run 100 pct water or you can run 50 pct Alcohol (iso, meth, denatured). Just dont run more than 50 pct alcohol. Most of the time I use 100 pct water.

The water injection doesn't "Lean" your engine out. For example, lets say your car is tuned for 12 lbs of boost WITHOUT the water injection. Lets say also that you know 100 pct fact that after 13 lbs of boost your car will detonate because of the "lean" condition. The water injection if set up properly may allow you to run 15 lbs of boost safely (this is assuming your injectors/fuel pump can keep up). So even though your car is running somewhat lean, the water injection is able to compensate by cooling the combustion chamber dramatically.

Im not recommending that anyone puts water injection and run crazy boost or even tunes for water injection. While I am confident that water injection is far superior to any IC, the reliability is not there and there is maintenance involved.

I use water injection on a dual stage setup that turns on at 9 PSI. My car is my daily driver and the water injection is full time.

 

I see, thanks.

a few questions then. One being why do you run 100% water and not 50/50 with methanol alc. Wouldnt the second option present greater results in terms of cooling?

second question, what boost do you drive at for your daily driving (9psi?)

how big is your water reservoir and how often do you refill it? (you did say its on all the time right)

what is your water delivery rate? (is it something like 10% of the fuel so its in proportion with how much fuel is injected depending on haw hard you drive. Or is it a fixed amount)

what is the pressure in your wi setup?

Thanks!!

 

Your asking me all the hard questions, lol. Ok. I used to run windshield washer fluid because it is part methanol, part water. Then I started running water/ISO, finally I just used water. There are several reasons. Nothing prevents prevents detonation better than pure water. yes, if you use 50/50 Alc/water you will have a better cooling effect, but alcohol will burn..water will obsorb the charge. Running more than 50 pct alcohol will contribute to detonation, rather than preventing it.

For my Daily driving I'm not one of these psychotic rx7 owners that need to hit 9000 rpm every day, so I drive quite normal. I hit 10-12 psi on my first turbo quite often. I like to use it for daily driving for 2 reasons:

1) I will have no carbon build up in my engine, it will be steam cleaned as will my plugs.

2) I dont have to worry about a bad tank of gas.


My water tank currently is just a 3 QT laundry detergent bottle, no joke. When my 1 gallon container of MMO runs out I will use that. It sits behind the spare tire well in the turn signal assembly area behind the plastic body panel. I have to refill it every 3-6 days.

I have 2 X 1200 CC injector + 2 X 550 =3500 CC
that equates to 56 GPH. My two injectors are around 4.7 GPH.
at 80 pct injector duty my fuel is about 44.8 GPH. That makes me just under 11 pct water to fuel. I had to keep changing my injectors to find the right feel. When you have too much water your car will feel very soft, almost like an ignition breakup on high rpm.

thats how its calculated for me, and it works great. If I decide I want to up the water I will either change my 60 PSI switch to a 100 PSI, or I can upgrade my injectors.

 

thanks for the great info!!

did you make your setup yourself or is it a kit? Those aquamist kits look really temting, the once with the ecu for the injection, allows you to make maps and more. Pricy though... but very tempting...

 

Please explain how this can be? Alcohol wont absorb as much heat as water so it isnt as effective in that department, but alcohol is additional fuel that is added which will prevent detonation caused by a lean condition, right?



I run a 50/50 denatured alcohol/distilled water mix. It is amazing how clean my plugs are every time I take them out! It is also amazing how much effect the water/alcohol injection has on my knock sensor readings from the PFC. Before water I would usually get readings of about 100-120 when coming off full throttle, now I only get about 40-45. Well worth the $200 in parts to set up the system that the turbomirage page outlines.

 

I think the reasoning is because alcohol burns it causes more heat rather than obsorbing it. Again, 50/50 alchohol will cool better than just water, but 100 pct water is better for preventing detonation.

Here is AQUAMISTS reasoning:

10. What is the maximum alcohol/ water ratio I should use?
No more than 50%, otherwise you will increase the cylinder temperature rather than reducing it. Beyond that ratio, onset of detonation is more likely. Methanol freezes at -96 deg. C, 50% mixture will stop the mixture from freezing at around -40 deg.C.

 

im not shure on this but here what i think i've find out :
water will cool down your intake temp. dramaticaly and
clean up the carbon in the engine

alcohol will cool down your intake temps too, will act like a octane booster in the engine but will also produce more heat in combustion form

correct me if im wrong

 

^ What he said.

 

There is just something about spraying water into an engine that just seems strange.

 

True,

but there is something about rebuilding your engine every 30K miles due to detonation, that is even more strange.

You should feel how smooth the car runs at full boost with the water running. YUM

 

Correct me if im worng but dosent it also help in removing carbon from the inside of the engine, or am I talking about a different kind of water injection?

 

yes it does.