DIY Water Meth Injection System!
 

So since I've gone boost I figured I'd need something to get my charge temps down. Obviously intercooling is in the works but I wanted more. A friend suggested water/meth injection and I looked into it to find it:

• Drastically lowered charge temps
• Steam Cleaned your pistons and cylinders
• Created even more pressure to push those cylinders down

I looked at a few kits from Devil's Own and Flying Miata but they ranged from 4-800 and I figured since it's just a few simple things I could build one myself.

So I did!

If you choose to do this I recommend checking out http://www.turbomirage.com/water.html

My system is based on theirs with a few add ons. Either way most of the parts I used are from that site so if you're wondering about anything you see in my writup check there for the part number.

So here's the basic idea:
http://turbomirage.com/waterpix/waterinjection.jpg

It's pretty simple when you get down to it. The water comes from the reservoir (I used my windshield washer tank but remember if you take this route that the washer tank isn't very large so expect to fill it once every 4-6 days) into the pump, past the water solenoid, through the nozzle, and into your intake. Obviously you'll want to rig up a way to have it turn on automatically and for that the relay and the pressure switch work fine.

In addition to those plans I installed a tank level meter to make sure I don't run out, a master switch so I can kill it if something goes wrong, and an LED to let me know when it's pumping.

On with the pictures!

The first thing I did was delete my charcoal canister. I wanted my entire system under the hood and that was the only place where the pump would fit. With it removed I installed the pump (upside down to help with the gravity feed from the reservoir.
http://www.mx5atlanta.com/forums/pic...&pictureid=667

Then I ran the hose (3/4 fuel line) from reservoir, to pump, to the water solenoid. This bit ensures no water can be sucked through the system when you don't want it to be. To keep it simple just wire it with the power for the pump so you can ensure they're both on.
http://www.mx5atlanta.com/forums/pic...&pictureid=668

Then I ran the hose from the solenoid to the actual nozzle but first I had to put it together. Remember to use plenty of teflon tape when doing so to ensure a water tight seal:
http://www.mx5atlanta.com/forums/pic...&pictureid=666

Next was to install the nozzle into the intake. I chose to use a pre-tapped 1/8 NPT hole that was in the dummy throttle body. Obviously if this won't work for you try anywhere before the throttle body. But make sure that you place it AFTER the IAT sensor!
http://www.mx5atlanta.com/forums/pic...&pictureid=670

Sweet, so now all my hoses are hooked up and water is ready to flow. To handle the wiring just follow the instructions on the site and it's pretty straight forward. With this setup the system will only activate under a certain PSI with the car on. That's the purpose of the relay. Pay attention to the wiring diagram in the first post to ensure you wire it correctly. Then wrap it in some electrical tape and tuck it under the fender.

But to get the psi right you'll need to adjust your pressure switch. First make you your wiring is right as one terminal closes under boost while the other opens. When it's hooked up attach a bicycle pump with a pressure gauge to your vacuum hose and pump till the system activates (do this with the hose unattached from the nozzle so you're not pumping water into the intake with the engine off!!!!)

Now you can adjust the switch with an allen wrench till the system turns on at the desired boost. Loosening the allen bolt lowers the boost threshold and vice versa. Just start high and work your way down. You want it on at WOT and maybe a little below.
http://www.mx5atlanta.com/forums/pic...&pictureid=672

Finally I also wired an LED for the low tank sensor. I made sure to get the brightest one I could find for this and believe me it IS bright!! I wanted to make sure that even in the sun with the top down I would know. The only irratiting thing is during fast cornering it will flash if the water sloshes around but I'll live.
http://www.mx5atlanta.com/forums/pic...&pictureid=671

A Master Switch so I can shut the whole thing down. Notice I use a switch with an LED. I want to KNOW when my system is activated; not pounding on a switch at full boost trying to activate the system.
http://www.mx5atlanta.com/forums/pic...&pictureid=669

And a second LED wired in with the pump's power to let me know that it's on:
http://www.mx5atlanta.com/forums/pic...&pictureid=673

And voila!! Now I have water meth. If you have any questions let me know and hopefully I can answer them!

what is your plan for a pluged nozzel?? you know thats why most systems fail.. ask me how i know.... other then that thats a good system..

That's something I've been thinking about and looking for a solution to. If you have any ideas please let me know.

Thanks!

Filtration coupled with periodic nozzle inspection will help.

Off to the WI forum we go!

Thanks Mod, I wasn't sure since it's a DIY thing.

Do they make a device that would let me know if the systems not flowing correctly? I suppose I could re-wire my warning light somehow that would turn the light off if the pump hits it's psi threshold and turns off.

We're all about DIY, dude.

There are some inline flow-metering devices available (one example).

For what its worth, I've had two failures over the past four years or so that I've been running WI. The first was a broken tee-fitting that caused a loss of pressure, and my failsafe caught that one. The second was a nozzle blockage caused by the complete disintegration of the filter screen on the nozzle, which I attribute to running a cheap nozzle and using too much methanol (roughly 50%.) I now run pure distilled water in the system.

Thanks for this write up, gonna save this one for later :D

um you dont need a selonoid or a relay on that system. other than that it exactly what you get when you buy a kit so i dont see your inovation still im glad to have another meth head around here. :)

If you get rid of the solenoid, you need a check valve. How can you get rid of the relay?

Technically you're right. I could have just wired the pressure switch directly to the pump and took the solenoid out completely.

However I like the added safety those two items give me. Lets say a contaminate gets into the system and somehow fouls the pump so it doesn't close all the way. Then I'll have my engine sucking the water in at vacuum which I definitely don't want.

I also like the idea of the relay, which won't activate the system unless the four criteria are there (12V constant, 12V with ignition, master switch, and pressure switch). I just like the added safety even though it isn't really necessary. The relay also gives you some options. Let's say you only wanted the system to activate above 5K RPM, well you could wire that in.

I also never claimed to be innovative, just cheap ;), there's a qualitative difference

you dont need a check valve i dont run one on either of my systems and to get rid of the relay run a good heavy duty switch duh. The straight fused 12v hot is awesome for the initial setup and trouble shooting so you dont run your battery down with the fuel pump etc.

The rpm activation point is rather weak. But that is why i have a manual 12v switch over option on mine. 3 toggles one for WI boost sensor sourced ground, one for boost gauge light sourced ground, and a crossover switch so that either circiut can run both.

Duh yourself. So you run the pump straight from the pressure switch? Seems marginal for current capacity.

Seems like the relay and solenoid are cheap and easy enough to install for the benefit they give. Just sayin.

he put together this kit for about half the price of the Devils Own kit, if im not mistaken.

Total cost was ~$180, install time was about 5 hours but that includes beer breaks, rides to parts stores, and driving/adjusting the pressure switch. The cheapest kit Flyin Miata offers is $419 and I couldn't find a kit for the miata from Devil's Own on their site. Of course the kits are usually trunk mount so they come with a SS line from trunk to engine compartment and some kind of controller.

Coolingmist.com does sell a kit for $225 but it doesn't include a tank level sensor (or tank). It also has a weaker pump, no water lines, fittings, hose clamps,, and all the other stuff that adds up quick.

Also, to make the case for the solenoid over the check valve: Remember that when the system is activated then turned off the pressure in the hose (from the pump to the nozzle) will still be there and the system will squirt for a second or two after the system is turned off. This is a waste of water/meth at best. Now with a check valve the pressure will be relieved from the pump to the nozzle. With a water solenoid the water will be STOPPED at the solenoid and less water will be wasted by pressure relief. I actually plan to re-run my hoses to put the solenoid just a few inches from the nozzle to help with this. Not to mention the pressure in the hoses will stay there and it will make the system quicker overall.

I just ordered the bigger parts for this, still need to pick up the fittings and stuff I can get local. I will be doing the tank sensor as well.

This is the sensor I used:
http://www.alcoholinjectionsystems.c...duct_info.html