Of course you need it, silly.

A few years ago, a huge hype entered the aftermarket automotive world: the introduction of affordable “water meth” kits. In the past few years, the hype seems to have died down… but I’m confused as to why?

I mean… yes, E85 hit the mainstream market there for a while, but as quickly as E85 fuel stations came they also went, and it became harder and harder to buy this great racing fuel substitute. On the other hand, water/methanol injection gives you some of the benefits of E85, along with several unique benefits. Plus, water meth mix is cheap and easy to acquire. The benefit to cost ratio is good and, for anything forced induction, it’s also a safety net.

Now when you hear the phrase “water meth” for the first time, your mind might wander to thoughts of people missing their teeth, wearing mismatched shoes and flannel shirts with no sleeves and wonder how that is going to enhance performance on your car? Well, other than getting your car poorly washed for a dollar there might be some confusion.

What is Water/Methanol Injection

Water/Methanol injection on a gasoline engine is a means of introducing an atomized mixture of water and methanol fuel into your car’s intake (or cold charge pipe) as a means of reducing air inlet temperatures, and increasing octane to suppress this nasty little thing called “detonation” or “knock.” Detonation is when fuel and air will ignite too soon in the ignition cycle, causing forces to expand in the combustion chamber. During detonation, the piston is still traveling on its upward stroke, but with the forces trying to push it back down, the energy is transferred and causes numerous effects, such as piston damage in the form of “piston slap,” where the energy forces the piston against the cylinder walls, and broken pistons and piston rings can occur.

Piston damage is rare in naturally aspirated engines of low compression, but occurs when most often the problem is allowed to go on unchecked.

Unfortunately, in forced induction vehicles that are turbocharged or supercharged, where fuel-air mixture volume and combustion temperatures are higher, one good knock can be catastrophic. Temperature is a major cause of detonation, but poor tuning and mechanical problems also possible culprits.

Enter a water and methanol system!

How Does Water/Methanol Injection Work?

There are many companies that make water/meth kits, such as Snow Performance and AEM. No two are exactly the same. Some are very basic and affordable, and others are a bit more expensive and more complicated. Most kits have 4 basic components: a tank, a pump, a nozzle, and some sort of control unit. Some are manually controlled and others are electric control.

What is Water/Methanol Injection and Why Do You Need It?
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Let’s take the AEM kit I’ve used on a few different vehicles. It comes with a control unit that has a built-in boost sensor and two control knobs. With one knob, you control where PSI of boost the system starts spraying the water meth mix, and the second knob controls which PSI stops it. The unit also has a light on it to tell you when your tank is running low. On this system, the amount of water meth is controlled by a “jet” that goes in the water meth nozzle, and then into the intake system.

What is Water/Methanol Injection and Why Do You Need It?
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On a turbocharged vehicle, the nozzle goes into the pipe just before the throttle body.

Typically, the water meth tank goes in the rear of the vehicle, with the pump right next to it. Most kits also have an optional filter you can add as well. The mixture is pulled from the tank by the water meth pump in a nylon tube. The tube then goes out of the pump and up to the front of the vehicle to the nozzle. Installation is not complicated on most systems, but some systems like the brand Aquamist get tied into the vehicle’s electronics as well. These are fantastic systems but can be very complicated to install yourself. Most basic water meth kits can be installed in an afternoon by anyone who is decently handy around a car.

What’s the Best Water/Methanol Mixture?


The water-meth mixture is also not a complicated thing. You can choose to mix it yourself in different ratios, but the standard that works for most people is a simple 50/50 mixture of methanol fuel and distilled water. I always choose to buy 4-gallon packs of Snow Performance “Boost Juice” (because at $40 shipped, it saves me time and effort I’d like to spend on other things). The amount you choose to spray with your chosen jet is usually defined in the instruction manual of the system’s manufacturer by horsepower and displacement.

What is Water/Methanol Injection and Why Do You Need It?
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On a gasoline engine, a little goes a looooooong way because of cooler temperatures, faster turbo spool due to the denser air, and your combustion chamber being steam-cleaned at the same time. Does this damage your engine at all? If you use too much because you didn’t bother following the directions, then yes, it can lead to damage to your engine, but for the most part, no. In my years of installing these systems, I have never personally encountered a problem with either tuned and untuned vehicles as long as you use your brain. From stock vehicles to modified vehicles, it is an extremely unappreciated modification to have and definitely something you should think about yourself.

Stay Tune’d

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