Water Injection - A stealthy approach
 

I have been meaning to install a water injection system on my supercharged MX5 for some time.

The car had to go through massive surgery since the "accident" back in December, so all plans had to be put on hold for a while. All I could do was order and gather parts and pieces during the almost five month period.

Anyway..

I would like to thank Joe Perez and ZX-Tex for giving me ideas and help to get this whole project off the ground.

I wanted the whole thing as much out of sight as possible. There is minimal trunk space to begin with, and any sort of a reservoir in there would make the trunk pretty much useless.

So, I developed a few ideas:

One was to make custom water tanks to fit in the rear wheel wells. Besides a plumbing nightmare that would create (balance lines between tanks, for instance) the available volume was really not worth the hassle once I put the car on a lift and examined the openings around the wheel wells.
Scratch that idea..

The second one was removing the spare, and making a custom water tank to fit in the spare tire well. That would hold plenty water.
So, I proceeded to plaster cast the whole area to make a mold for vacuforming.
But there was again a volume issue.. Too much water. Too much weight. Little room for the pump, etc, and one little warning about the pump having to be below the water tank level.
Scratch that idea, too.. And the massive plaster cast became a part of the landfill:
https://www.miataturbo.net/picture.p...pictureid=1104

I am having trouble seeing the pictures. Where are you putting them?

So, the third idea was to build water tanks to fit in the openings on either side of the gas tank in the trunk..
The left side opening is visible in the pic:
https://www.miataturbo.net/picture.p...pictureid=1113

Turns out, two tanks in these openings carry about 10 liters (about 2 1/2 Gal), which is plenty.
My main concern was running out of water on the freeway.

I proceeded to make the water tanks..

I searched for what I could use, and settled on 1 mm thick clear pvc.
Here is the prototype: (Those measurements are not in inches.. Also, 14.5 cm was a much better fit than 15 for the width.)

https://www.miataturbo.net/picture.p...pictureid=1096

I first drew and cut out the basic shape on the pvc, and then used CA glue and some seriously tough water resistant silicone (Bison PolyMax) to glue the edges.

https://www.miataturbo.net/picture.p...pictureid=1097

I made a bending/folding tool using 3/4" mdf and a piano hinge.

I cut two 60X10 Cm and one 60X15 Cm piece of mdf boards, and joined them very carefully with the piano hinge.

Worked great with the help of the heat gun..

https://www.miataturbo.net/picture.p...pictureid=1099

https://www.miataturbo.net/picture.p...pictureid=1100

I also bought an AEM 30-3001 5 Gal. progressive water injection kit.
(5 Gal kits come with a larger, beefier pump)

The idea was to use the level sender out of the kit's reservoir.

I also bought various plumbing fittings and pneumatic fittings to route the water lines..

(Excuse the silicone mess, that stuff gets trimmed once it dries..)

https://www.miataturbo.net/picture.p...pictureid=1133

I also wanted to make a cool filler..

So, I used the only logical spot for that, and fabbed a filler neck, complete with an air vent to prevent air lock in the water tanks.
https://www.miataturbo.net/picture.p...pictureid=1112

The air bleed/vent is a 30 micron mesh filter. No dust or dirt could get in..

https://www.miataturbo.net/picture.p...pictureid=1115

Pics are showing up now. And, WOW this is serious!

I wanted to use the AEM kit to a certain extent..
What I really want is a direct port injection system.

So, I made some calculations, and ordered four 70cc nozzles, and "T" connections from Aquastealth.

https://www.miataturbo.net/picture.p...pictureid=1102

Aaand, promptly bıuilt a test stand to test the nozzles..

The results speak for themselves..

https://www.miataturbo.net/picture.p...pictureid=1108

Here is the test stand:

https://www.miataturbo.net/picture.p...pictureid=1106

https://www.miataturbo.net/picture.p...pictureid=1105

https://www.miataturbo.net/picture.p...pictureid=1107

(Yes, that's my teacup on top of the water tank. Takes about half a quart..)

And clearly this is an understatement.

I used some pretty large fittings for the fill tube just to increase the available volume, just like the old NASCAR trick:

https://www.miataturbo.net/picture.p...pictureid=1118

I could not find washers for those tank fittings, so I made them out of a PVC down pipe (the kind used for rain gutters)

https://www.miataturbo.net/picture.p...pictureid=1101

Thanks, there is more... :)

too legit, I love the filler idea next to the gas fill, super logical as long as you dont let dumb fucks fill up your car (Oregon, NJ anyone?)

The progressive controller went under the dash, I made all the connections, extended the wires for the pump controller and the level sensor, and found a killer spot for the diagnostic/status LED...

This is with the LED on to illustrate the point.. Hard to miss.

https://www.miataturbo.net/picture.p...pictureid=1139

And it is not the least bit offensive when it's off:

https://www.miataturbo.net/picture.p...pictureid=1138

The other group of LEDs at the center are my knock indicators, BTW.

And, here it is in the dark:

https://www.miataturbo.net/picture.p...pictureid=1137

Before I forget, I had the steering wheel re-covered with hand stitched leather a few months back. Turned out great, and I paid the guy about $60 for the whole thing..

Then, I removed the plenum, and started thinking about routing ideas..

(Note, a very important lesson coming up: never make critical decisions past 3am.. Fail becomes imminent..)

https://www.miataturbo.net/picture.p...pictureid=1120

https://www.miataturbo.net/picture.p...pictureid=1121

Everything was cool up to this point...

Then, I had a brain fart.

For some reason, I decided to install the nozzles on the opposite side of the plenum, and happily proceeded to drill & tap... :loser:

https://www.miataturbo.net/picture.p...pictureid=1124

I happily proceeded to complete the installation failure, and went to bed, feeling tired and stupidly content..

https://www.miataturbo.net/picture.p...pictureid=1123

https://www.miataturbo.net/picture.p...pictureid=1126

https://www.miataturbo.net/picture.p...pictureid=1125

https://www.miataturbo.net/picture.p...pictureid=1127

Awesome all around job commie! :bigtu:

Nice to see that you can also make mistakes (I'm referring to where you placed the nozzles on the plenum) :giggle:

Can you also expand on the LEDs knock indicators?

Did you start a thread on that subject?

Keep up the good work for guys like me (mechanically challenged) :giggle:

Hell, I even did some trial setup to see what the plumbing would be like..
(Blue lines are for practice only, BTW. They are 6 mm, as opposed to the 1/4", which comes to 6.3 mm, and makes installing and removing very easy for trial fits.)

https://www.miataturbo.net/picture.p...pictureid=1129

https://www.miataturbo.net/picture.p...pictureid=1130

This morning I jumped out of the bed yelling "Laminar flow!"...
My wife had no clue what I was talking about.

I ran out, found some 1/8 NPT plugs, and covered up my shame with liberal amounts of teflon and those four plugs..

(No pictures of that.. I was a bit pissed..)

Ahem..
I did drill & tap and install the nozzles in the correct locations, of course..

And it took a bit of trial and error to find the connection scheme that I liked..

https://www.miataturbo.net/picture.p...pictureid=1135

https://www.miataturbo.net/picture.p...pictureid=1136

(BTW, the car is not an automatic, the reason behind two throttle cables is the dual throttle setup I have built a while back. That thing is a MUST for all hotside S/C setups.)

You can also see the 1/8 plugs on the plenum... The only upside is, if I ever need another vac/boost port on my manifold, I have four of those ready..)

Next step will be installing the water tanks, hooking them up, and buttoning it all up..

The silicone on the water tanks needs to completely cure so I can do my final leak test before I commit to anything..


Oh, I will be running straight water in this system. I found a chemical supply company where I can buy up to 50 liters of distilled water at pennies/liter at a time.

I'll post my progress as I go.

Wow great write up! Can't wait to start on my water injection setup, this is really motivating hah. Thanks for the contribution, looks amazing to say the least.

Thanks!

The LED knock indicators are sold at www.knockgauge.eu, and are made by a guy in Lithuania.
You can either buy a gauge, or the kit version like I did.
Buying the kit version gives you the freedom to install it wherever you like..
And the thing works like a charm.
And yes, life would be pretty dull without mistakes.
All is fixed now.

Looks great so far, can't wait to see the finished product. :bowdown:

Wow... This is really cool, really! I do not know where to start with the questions.

OK so where you put your nozzles the first time... I seriously considered placing them there but I did not think they would fit. Looks like they do, just barely, at least with the Aquastealth nozzles. So I am wondering why not just go ahead and run them there? Oh wait, you have not gutted your manifold right? I cannot tell from the photos. I think with a gutted upper plenum that putting them there is a nice idea. They fill the upper plenum with mist which helps with redundancy per my other discussion. Plus, they are directing the spray right into the throat of the runners which should also be good. Makes me think about moving mine there actually.

But that aside I like where you placed them on the upper portion of the manifold. If you have to mess with it, clearly it is easier to remove the upper portion than the lower portion. I did not place them there because I was concerned about hood clearance. But again, at least with the Aquastealth nozzles, they fit.

So I am guessing your progressive system is PWM on your pump motor? Have you played yet with the duty cycles to see what the mist quality is at low percentages? I'm curious about that for sure.

I think that bending tool you made for bending the PVC is great. Why I did not think to build something like that for all of the heat gun ABS bending I have done... it's not like I have never seen a sheet metal brake before :facepalm: Next time I bend some ABS I am building one of those for certain :)

This is beautiful.

There is, however, one problem.

http://img40.imagefra.me/img/img40/6...gm_b36cfa7.jpg

Sup fellow engineer! :D This thread is AWESOME.

Awesome. Mebbe I will do direct port; plenums are cheaper to fuck up than blocks.

word qft
And, especially for the upper on the NB, a hell of a lot easier and cheaper to replace.

i seriously almost just pissed myself

I would love to see a comparo of IATs or something from a single nozzle system pre-TB and a direct port system. That is one badass setup.

Pretty much all the systems out there are PWM to the pump as opposed to variable voltage, its much better for pump longevity. Commie', one thing to consider here is that the newer pumps being used by pretty much everyone are much more reliable, but they have one hang-up for install. That is the fact that they have inlet and outlet fittings going right into the head-unit of the pump, no swivels. I have seen swivels available for them, and IMHO they are a bucket of crap, especially on an system you have put a lot of time into like this. SO when you do the pump location, you might want to make some allowance in regards to postioning and tube-routing so that if you do switch to the newer style, your not re-inventing the wheel.

Yes just making sure he was not using an HSV like mine. I'd like to see his 'threshold' duty cycle.

.

Yes! And I do not like it. My new DO recirculating shurflow is like this; the hoses go right into the pressure head. My old 150 psi pump (switch regulated) had fittings that I had nice DO 90 deg swivels on. Definitely more adaptable. I still got the new pump to work as-is with a little hose rerouting. But for someone with a really tight space it might not be so nice.

Maybe those quick fittings screw out of the head to reveal NPT fittings but I have not messed with it since mine fit as-is.

Looks like they are press pressed in to me. The newer Auatecs are pretty badass, I had an older Shurflo pump in my Snow system that was great, but the Aquatecs seem to be smoother (recirc as standard, not retroed on) higher pressure, and also significantly lower amperage draw. A big Shurflow can pull almost 20 AMPs. Thats a lot of fricken juice at WOT. But the fittings are a PITA. I will get one when I get the darned car, but I will be putting some real thought to pump placement in relation to the tank.

Done.

I finally buttoned it all up and had a chance for a test drive.

The result is very pleasing to say the least. I even added a couple of degrees of timing at the 3500 rpm range and did a couple of hard pulls on a long uphill portion of the freeway under the pretty hot noon sun... no ping, just smooth power.

The only thing that bothers me is, I had no way of getting clear across town to get distilled water, and used tap water instead.
I'll drain the tanks out and flush the system with distilled water as soon as I can.

I am planning on running straight water. Did a bit of research on the history of water injection; turns out alcohol was originally introduced into the mix as an anti-freeze agent back in the thirties and forties when this technology was used exclusively on military aircraft.
And water alone meets my purposes perfectly.

I will post pictures of the finished setup as soon as I can take some pictures during the day.

So did I..

* I will be able to compare the EGTs as soon as I install my LMA-3. All I have to do is make run with the water injection disabled, and then one with it running..

* The kit I bought came with the bigger pump, and it sure has the swivel inlet and outlet fittings on it.
And, in the case you have a pump with fixed fittings, you can just google the nearest "Legris Pneumatic Fittings" dealer, and buy exactly what you need to do your plumbing. That's what I did for some of my tank fittings - I needed quite a few of those, one to feed the pump from the left side tank, and several to vent the tanks outside the car.

Yes they do. You can remove and reinstall them, but take care to avoid over-tightening. Just use teflon tape.

True, but considering the actual time you spend in boost, that's not much. People drive for hours on end with their amps cranked - and not at elevated RPMs, mind you - and those amps are not exactly power misers..

Awesome!

Its just such a great feeling when you can put the car through a really high load situation with 0 knock. Its like a weight off your chest.

Thats great about the fittings, I did not know that. Makes installtions a lot easier for sure.

I honestly think placing the nozzles on the top side like I did the first time around will be a mistake..
You will simply be starving #1, and drowning #4 that way.
The thing is, the nozzles will never be able to spray straight down in real life conditions. There is considerable airflow to direst the water spray sideways, towards the back of the plenum when the motor is running, especially in boost.
A pre-TB single nozzle would be far more a logical approach compared to four in-line nozzles inside the plenum.

Locating the nozzles inside the runners is a different, and much better solution since this method does not subject the water mist to laminar flow. The air at that particular point in the runner shall simply carry the spray from the respective nozzle to the intended destination, which is the corresponding combustion chamber that runner leads to.

A gutted out manifold would be much trickier to deal with in this very respect IMHO.

And, that was a 5th gear pull from about 2250 rpm!

None of the water injection outfits disclose that information for some reason. A bit of curiosity, a magnifying glass and google pointed me to the right direction.

Does this mean you can't buy distilled water for your battery at any gas station in Turkey?

That's really weird. I can even buy it in some large local supermarkets. Now, methanol is another matter.

Of course they do.. They have those dinky little bottles they sell for about 5 bucks each.. Would take a lot of five dollar bills to fill the system for leak checks.
(I did several leak checks on the tanks off the car of course.. Leak checking in the car, with everything connected in real life conditions is another matter.)

There is an industrial supply company across town where I can buy distilled water 50 liters at a time for about 15 cents a liter.. Comes to $7.5 for five tankfulls!

Methanol is about 3 bucks a liter...

BTW, tap water is often going to be just fine unless it has a tremendous amount of calcium and all in it. It would take quite a bit of build up to hurt a pump or clog a nozzle.

Good to know

You know, now that I think of it that way, I think you may be right.

I am straddling the line between plenum spray and runner spray with the gutted out manifold. It is part of my redundancy scheme. If one runner's nozzle clogs it can still draw some water in from above the adjacent runners. But because of the way I have positioned the nozzle at least half of the spray for a particular runner is going in that cylinder for sure during its intake stroke.

But, all that being said I still agree that the top nozzle approach may not be ideal after all. Scratch that idea. I'm staying with what I have.

Well put. Totally agree.

FWIW I just bought a Innovate TC-4 so I am going to be able to log EGT as well; the Adaptronic will log a TC-4 and an LC-1 at the same time. The EGT probe is already in the collector, pre-turbine inlet. I plan to do the same and I am looking forward to seeing the logs.

All I need are my fuel injectors which will be back here next week.

All finished..

Here's how everything is installed and buttoned up.

http://www.mazdaclubtr.com/MGalleryItem.php?id=4398