When many people hear "water/meth injection", thoughts of danger creep in. Horror stories run rampant out there about those that have blown their motors running meth and how dangerous it can be. However, a lot of the rumors and the fear factors surrounding water/meth injection simply aren’t warranted.
There are multiple benefits to running a water/meth Injection setup on your boosted performance car especially with the new direct injected cars that are starting to become the norm from auto manufacturers. Potential advantages include valve cleaning, charge air cooling, increasing your limited DI fueling window, and most importantly, it can give you some pretty big performance boosts.
So leaving aside all the performance benefits in terms of power that you pick up with a good water/meth kit, the valve cleaning alone is what makes it worth it for most people who own a Mazdaspeed, a Focus ST, the FA20DIT powered WRX, BMW N54 or N55, or any other direct injected car. With direct injection no fuel gets sprayed on the back of the valves, then you add on EGR, an obscene amount of oil that comes through the PCV System, and you get quickly gunked up valves that over time, will hurt performance and fuel mileage. Methanol makes for a very strong cleaning agent and will clear away the gunk that builds up on the valves and keep your engine running healthy and happy.
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| Dirty intake valve with no natural port injection cleaning | Valve and intake runner after a short time using methanol injection |
As to the charge air cooling, methanol has a very high latent heat of vaporization compared to gasoline. Because it vaporizes at a much lower temperature than water, the meth will pull heat from the intake tract, the piston crown, and the valves. The cooling of the boosted air in the intake manifold allows for a colder denser charge as it enters the cylinders. Keeping the piston crown and valves cooler helps to reduce hot spots that would otherwise start an uneven burn (detonation) in the cylinders.
Below, we've charted out a back to back datalog comparison of a car before using methanol injection and then immediately after. This is the same care with the same turbo and performance parts, first without the methanol kit and second with it. The boosted air temps (post intercooler) drop off significantly.
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| Although this intercooler is actually very efficient, the temperature still rises above ambient. |
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| Add in methanol injection and the temperature actually drops BELOW ambient. Lots of power to be made with this low of an intake temperature. Even more impressive, the boost level is set even higher on this second datalog which would normally create even hotter intake temperatures. |
I could stop typing now and you would have enough reasons to start looking at meth kits, but I can’t stop here because… “But wait! there’s more!”
Direct injected cars like the Ecoboost Focus ST and Mustang, the Mazdaspeed 3, and the FA20DIT WRX have quite a lot of head room when it comes to the factory fuel system. Where most port injected cars run out of injector, the DI systems will generally keep going. However, once you hit the limit, there isn’t a lot you can do. The Ford Ecoboosts have a few aftermarket options for injectors which will get you just a little bit more head room, but for the most part the DI cars we deal with are all going to be limited to around 400whp. This is a great stopping point for some, but for a lot of people, there is no such thing as a stopping point. So one of the options you have is to run a methanol setup to help supplement fuel. A good meth setup could get you another 100whp worth of head room and in some cases more.
All in all, you open up a whole other world of possibilities with water/meth injection. Not only can you make more power and make it more reliably, but you can also extend the life of your engine by keeping everything cool and clean on the inside. As to the risk vs. reward? Reward comes from a good quality Water/Meth setup that helps to minimize the potential for risk and mazimize the potential for a successful setup.
Example of a dual nozzle setup entering in the intake piping. Photo courtesy of trucktrend.com.
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