WMI Part 2

Welcome back to another Water Methanol Injection article. If you find yourself here and haven't reviewed Part 1 then you'll probably want to give that a read before proceeding.

To read Part 1 Click Here

Summarized, part 1 outlines the two major uses for Water Methanol Injection (WMI). One main use is for temperature control, the other is for additional octane and supplemental fueling.

In this article, we're going to discuss the major components of a WMI Setup.

Snow Performance Stage 3 Kit

Water Methanol Injection Kits comprise of 5 major components;

  • - Fluid Pump
  • - Fluid reservoir
  • - Injection Controller
  • - Nozzles / Jets
  • - Fluid

The majority of the fluid pumps on the market are produced by Aquatec and are often built to different standards depending on what the manufacturer requires.

Pump Exploded View

The pumps contain EDPM seals which allow them to be chemically compatible with 100% Methanol, however, it is not advised due to the low flash point of Methanol, as well as the minimal benefits and increased costs. A 50/50 mixture has been proven to offer the best knock suppression and cooling. (discussed in part 1)

Due to the fact that many WMI systems utilize the same pump, mounting solutions are plentiful and fairly universal.

Pump Dimensions

Most of the pumps on the market have a 300psi maximum output, however many of them are turned down via an adjustment screw located on the pump to the manufacturer’s specifications.

Fluid Res title

Most fluid tanks are made of a corrosion resistant polymer and are injection molded to the desired shape by the manufacturer. Tanks come in all sorts of shapes and sizes to fit different applications. AEM V3 kits are now coming with a slightly larger tank to help extend the fill intervals, while Snow Performance kits often come with a 3-quart tank with an option 2.5 gallon upgrade.

The 2.5 gallon tank from Snow is probably the largest tank you want to stuff into a streetcar, but there are also other options available from Aquamist, Devils Own, and US Plastics

Snow Performance 2.5G Kit

Some users prefer the stealthy approach of reusing their existing washer fluid tank with a bulkhead fitting, while most choose to use the provided tank from their kit or an upgraded tank. While there is nothing wrong with using the OE washer tank you have to be aware that the OE washer pump may not be designed to take the higher content of methanol. While washer fluid can be used in place of a 50/50 mixture, we'll discuss that further on in this article.

If you're going to be mounting the tank in the trunk you're absolutely going to want a solenoid and/or a check valve to prevent gravity siphoning into your injection site. 

Snow Solenoid

The wiring of the solenoid should always be as the manufacturer specifies. But usually, the pump power wire and the solenoid should be tied together so the solenoid only opens when the pump is triggered.

Snow Solenoid Wiring

Check valves are also often used to help aid to prevent siphoning of fluid, these check valves often have a cracking pressure of around 30psi which even the weakest pump should be able to overcome.

Snow Check valve

When you're mounting your tank, you'll want to do a bit of planning as to where your pump is going to be located as your pump is only gravity fed so your tank will need to be higher than the pump to allow proper feeding. 

You can also buy some really slick tanks that have built-in pump mounts such as the Universal Fitment 3 Gallon Trunk Mount Tank from ProMeth

ProMeth Tank With Pump

Injection Controller Title

Injection Controllers is where everything gets really interesting as there are so many ways you can control WMI. Generally speaking, there are two types of controllers; 

Static Controllers, and Progressive Controllers. 

Static controllers are like a light switch, it's on or off. And Progressive controllers are more like a dimmer switch on a timer. You can start dark and work your way brighter based upon what you want or preset parameters. In our case, the main parameter would be boost pressure.

Most kits on the market come with some type of controller, and depending on the "Stage" of the kit it will vary. Some of them are extraordinarily simple and operate on a Hobbs style switch (a pressure/boost activate relay) that triggers the pump, and others are highly programmable and extremely complex such as the Aquamist HFS-4 or even the Snow Performance VC-50. 


How you decide to control your WMI is entirely up to you and a lot of the prebuilt kits offer great options which are ideal for beginners. But for the more advanced users, the Aquamist HFS-4 and TorqByte CM5-LT are on the top of the totem pole for absolute control.

TorqByte CM5-LT

TorqByte Software 
TorqByte Software Pictured Above

Water Meth systems can be had for an affordable entry-level price, and with a couple of add-ons you can really make a custom fit kit that suits your needs. Or you can go hog wild and spend a small fortune on controllers, tanks, pumps, jets, etc. How far down the rabbit hole you go is entirely up to you.

If you live somewhere that has poor fuel quality, you can’t source other means to fuel the car like Ethanol or Race Gas and you just really need to make power. Water Meth Injection is your only remaining option. On an octane/methanol dependent tune, you’ll definitely want a more in depth set-up including safeties, fast acting valves, etc. For that style of application it’s best to get with your EQT sales rep and figure out what you need. 

Later on in the next article, we will discuss Best Practices, Tips and Tricks for setting up your Water Methanol Controller as the subject can get fairly in-depth depending on your setup.

Nozzle / Jets TitleNozzles are luckily one of the most simple components of the Water Methanol Injection system. Many manufacturers rate them in either cc's (cubic centimeters) or ml (milliliters) per minute which corresponds to how much fluid they can spray at their maximum rated pressure.

Aquamist, a leading manufacturer in the UK rates their nozzles/jets in CC/Min and provides a graph of their flow characteristics. Typically Aquamist advertised flow ratings are at 150psi of pump pressure. So you can see how if you do too much mixing and matching you may not know what the flow rate may be. 

Ex: Aquamist jets rated at 150psi, with a Snow Performance Ultra-High Output (UHO) pump being driven at 300psi

Most manufactures provide a reference guide regarding how big of a jet you would need for what your horsepower range is. However, there are times when you can end up in between sizes, at which point I would suggest you go bigger than you need if you have a progressive controller, and if you're using a static controller go to the smaller size. 

Snow Jet Chart

Snow Performance partnered with Nitrous Express a few years back and due to this joint venture, they've recently released new Nozzles/Jets which have a much wider range than they used to which makes jetting your WMI Kit a lot easier and precise. More on this later.

Fluid TitleFluid, finally. 

We mentioned above that we would loop back around to washer fluid when discussing tanks and using the OE Washer tank. YES, you can use windshield washer fluid. That's the question you were all waiting for. Yes, you can use it, but the more important question is should you use it?

Washer Fluid

Typically, Blue washer fluid is 30% methanol by volume, 68% water, and 2% other. It’s the 2% part that we need to pay attention to. The blue dye in washer fluid can crystalize and lead to a clog in the system, which if your tune is depending on that methanol to increase octane then it's not worth the gamble in my professional opinion. (WMI Dependent tuning covered in Part 1)

When I originally started playing with methanol I didn't want to shell out for the name-brand good stuff, the cost of a 5-gallon pail was a bit much for my budget and VP M1 is not cheap. (at least where I live) so I was using washer fluid and “spiking” it with three bottles of Yellow Heet. (which is 100% Methanol by the way)


Some of the WMI companies have said that in a pinch if you need to make a 50/50 solution and cant source pure methanol and distilled water, or Boost Juice (A Snow Performance product) then you can substitute in a gallon of blue washer fluid with three 12oz bottles of heet and it will get you there. While it works in a pinch, I've found that the dye and whatever else they put into washer fluid leaves this crusty residue throughout the system and I wouldn’t advise using it if you don’t absolutely have to.

Methanol has another name that may make it easier to find, some call it just "Methyl Alcohol" which is what you will find on the back of a bottle of Heet on its label.

Heet Label

Often times you can source what is called "Farm Grade" Methanol from your local commercial chemical store or tractor/truck supply store. Farm grade methanol is 99.99% pure while VP Racing M1 is a higher purity. And for the sake of auxiliary injection and not being a primary fuel source such as a Blown Alcohol Funny Car, it's not really important how pure it is as long as it’s Methanol. Funny Car

Other chemicals can be substituted in place of Methanol such as Isopropyl/Denatured Alcohol, but it’s much less effective and smell absolutely awful. 

Ideally, you'll want to source a 5-gallon pail of pure methanol and mix your own 50/50 solution using distilled water, or for sake of ease, you can purchase Snow Performance Boot Juice which is fully legal to be shipped and doesn't require any special treatment as it's 51% water, 49% methanol.

But keep this in mind, the convenience comes at a price, 51% water read that again. If a gallon of Boost Juice costs $5, you're paying $2.50 for half a gallon of water. You decide which route is more cost-effective for you.

Boost Juice

Part 3

Now that we've discussed all the individual components or at least the major key components of a Water Methanol System the next article is going to discuss tips and tricks, best practices, and how to set up your controller for your setup so stay tuned for that! 

Part 3 should be the Conclusion of this WMI Series.

Thanks for Reading!
- Dave At EQT

EQT Small