While naturally aspirated V8 Mustang models like the GT and GT350 might garner the lion’s share of attention from most enthusiasts, the performance capability of EcoBoost-powered Mustangs should not be underestimated. Along with putting less weight over the front of the car, the tuning potential of these turbocharged mills is quite impressive – and garnishing output that rivals that of the factory V8 is a surprisingly low-effort affair.

But as the boost goes up, so does the heat generated under the hood, and excess heat is the enemy of performance. Our 2015 Mustang EcoBoost has a typical assortment of bolt-ons – cold air intake, Gibson cat-back exhaust, custom 3-inch high-flow downpipe, Mishimoto intercooler, TurboSmart BOV and a custom tune – all of which helped the turbocharged pony dish out a totally respectable 300 horsepower and 338 lb-ft of torque at the rear wheels, along with low 13-second/high 12-second quarter mile passes on drag radials. Not bad for a mildly tuned, daily driven four-pot, eh?

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With the V6 option bowing out after 2017, the EcoBoost-powered model will now serve as the "base" Mustang. But don't let that fool you — this is a pretty lively four-cylinder, sharing much of its mechanical configuration with the mill installed in the Focus RS. With forced induction already in the mix straight out of the factory, there's also some real tuning potential here. This particular example is being setup for all-around, street driven performance, knocking out high 12-second passes at the strip on drag radials and tearing it up on the autocross and at track days when not pulling commuter duty.

Trouble is, upping the boost with that custom tune has resulted in skyrocketing intake air temperatures — both at the track and on the street —  causing sporadic losses of power and inconsistent e.t.’s. To combat this while seeking out even more grunt from the 2.3-liter engine, we installed a water-methanol injection kit from Snow Performance. Here we’ll go over the particulars of the kit, get some insight from the experts at Snow, and go through the key points of the installation.

Going Water-Methanol

While turbocharged engines like the 2.3-liter EcoBoost four-cylinder serve as a great foundation to build from they’re also highly susceptible to heat-soak, which causes the ECU to pull timing and in turn reduces power.

“A lot of modern factory ECUs are now programmed to maintain peak power all the time,” Matt Snow, of Snow Performance, said. “They use sensors to detect knocks, and if one occurs, it immediately pulls the timing to adjust.”

While that’s a great failsafe to have against damaging your engine, the other benefit of this real-time adjustability of engine timing is that if the ECU doesn’t detect knock, it will continue to increase the timing, too.

“It’s kind of like the car tunes itself,” Matt added. “It will carefully nudge up the timing — up to four degrees — on its own if the engine doesn’t detect a knock condition.”

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Snow Performance's 300-psi Ultra High-Output pump is said to offer the highest volume of any pump on the market, according to Snow. Designed to run cooler and maintain higher pressure for longer periods of time, the pump is fully sealed and potted for added reliability and protection from the elements, meaning no sleeve is required. While we used the included three-quart reservoir tank, Snow says that builders can opt to use the windshield washer fluid tank instead and simply plumb the lines into that for simplicity's sake if they prefer.

That can be a pretty significant change in engine behavior, which can unlock some untapped performance. But in order to reap those benefits of increased engine timing, those charge temperatures need to say low.

“Simply put, water-methanol injection is the best way to lower those IATs,” Matt explained. “So even in situations where peak horsepower is unchanged, the midrange can be improved significantly – smoothed out so there’s no stuttering or hesitation in the power delivery.”

Since the low- to midrange is where most street-driven vehicles spend the majority of their time, you’ll likely notice these improvements more often than gains in overall peak output. However, there are often benefits to be had at the top end, too.

“It’s actually difficult to get spark knock with this kind of system installed,” Matt added.

So not only can a water-methanol injection system stabilize the power delivery in turbocharged applications like this EcoBoost-powered Mustang, it can actually provide a significant bump in horsepower because the timing can be increased even further.

This isn’t a simple case of “more is better” though – there are a few factors to consider, particularly when it comes to Ford’s EcoBoost platform.

“Our system is based on boost as well as fuel pressure,” Matt explained. “With the EcoBoost, the fuel pressure is directly related to the horsepower output, so we need to time the sensor so that the injection curve is shaped for the way the boost comes on. That way we can dial it in so that the water-meth is introduced at just the right amount to maintain maximum power and efficiency throughout the rev range.”

For our mildly modified Mustang EcoBoost, Snow Performance’s Stage 2 Boost Cooler system was just the ticket. Available for all forced induction applications whether they be turbocharged or supercharged, the Stage 2 kit uses a progressive controller that proportionally injects for maximum efficiency. On an EcoBoost-powered Mustang, it equates to charge temperature drops of about 80 degrees on an otherwise stock vehicle – along with the potential to add more timing to increase horsepower, according to Snow.

“The higher the boost, the greater the IAT reduction you’re going see,” Snow told us. “We have a ’93 Cobra with a NASCAR motor that’s running 24 pounds of boost and we’re seeing about a 160-degree drop in temperatures on that one.”

Installation and Tuning

While installing the kit is a pretty straightforward proposition which can be done in a home garage without any specialized tools, Snow offers a tip that can simplify the process a bit.

“The easiest way to install the kit is just use the stock windshield wiper fluid tank,” he said. “You’d just install the Snow fitting in the wiper fluid tank and use it to both supply fluid to the injection kit and clean the windshield.”

If you’d rather use the supplied tank from Snow, you’ll get started by installing the level switch in that tank following the guidelines provided in the instructions before moving on to the reservoir installation, noting that the reservoir should install above the pump but below the nozzle. This keeps the pump primed and prevents fluid from leaking into the nozzle when not in use.

After installing the 3/8-inch NPT to 1/4-inch tube reservoir fitting in the bottom of the tank using the provided sealant and checking for leaks, the tank can be installed in the engine bay. We chose a spot just in front of the cold air intake’s conical filter.

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Once the tank is outfitted with the level switch and 3/8-inch NPT t0 1/4-inch tube fitting , it should be ready to be mounted in the engine bay. This spot just in front of the cold air intake’s filter worked for us, though we did need cut off a bit of the cooling system's top cover to make the fill cap accessible.

From here we moved on to the pump installation. While the pump can be installed in any orientation, you’ll want to position it so that the inlet is situated at or below the lowest point of the reservoir and within two feet of the reservoir. For EcoBoost-powered Mustangs, the back side of the bumper brace is usually the best spot.

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The pump finds a home on the back side of the bumper brace. While the unit is fairly robust, it's a good idea to minimize its exposure to road debris and other outside elements. Arrows on the pump inlet and outlet indicate the direction of fluid flow.

After taking care of the pump wiring, we installed the nylon tubing that goes between the reservoir fitting and the pump inlet, ensuring there were no kinks in the line and no stress was being applied to the push-lock fittings.

From there we selected the proper nozzle for our application based on the chart in the included instructions – nozzle #3 for this 300-rwhp Mustang – installed it in the nozzle holder, and mounted it onto the intake tubing by drilling and tapping the intake tube with a 11/32-inch drill bit and a 1/8-inch -27 NPT thread tap. Make sure you remove the intake tube from the engine before you go to town with the drill in order to prevent debris from getting into the engine.

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Fitting the nozzle (or nozzles, depending on your setup) will require creating an 1/8-inch -27 NPT thread tap within the intake system. Snow Performance recommends using a metal section of the intake piping for this, but if none is accessible, the plastic/rubber air inlet tubing will suffice.

With the intake tube nozzle fitting sorted out and all the plumbing hooked up, we then moved on to the controller installation, which we installed in a gauge pod on the driver side A-pillar. Once that was wired up and operational, it was time to test the system.

Priming the system involves filling the reservoir with water, removing the nozzle from the intake tube, placing it in an empty container, and pressing the button on the left side of the controller until fluid flows consistently through the nozzle.

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The system is controlled by a three-button gauge that provides tuning options as well as readout customization and a general interface with the injection system. We installed the gauge in an A-pillar pod.

After priming the system and reinstalling the nozzle, the process moves on to the tuning element. Snow says that this is where a lot of folks run into trouble though, as it’s easy to start with a mixture that’s too rich or timing that’s too advanced, which can lead to less than optimal results.

“The trick to making horsepower with water-meth injection is to test your car without it, turn the injection system on using the recommended settings, then trim the water-meth wherever there’s a dip,” Matt explains. “At that point you then start to add timing – otherwise you may be adding quench.”

Quench is a condition where there’s too much water, water-methanol, or fuel in the mix and the flame can’t propagate properly, which results in poor combustion.

Looking for a way to significantly lower your IATs while potentially adding more horsepower in the process? Give the folks at Snow Performance a buzz today and find out what their water-methanol injection kits can do for your turbocharged (or supercharged) project.