
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?
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.”
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 Snow, Snow Performance“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.”
The higher the boost, the greater the IAT reduction you’re going see. — Matt Snow, Snow PerformanceFor 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.
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.
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.
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.
Dialing In The Tune
Matt Alderman of ID Motorsports used SCT Advantage III software to develop a custom calibration that set the air/fuel and timing to maximize the water-meth combination, which usually means focusing on the timing curve.
“Using SCT allows us to take on remote tuning and know that we will get all the data we need to make our changes. Plus we never have a shortage of parameters available to us,” Matt explained. “When we tune for water-meth, we have to account for the extra fuel enrichment you get from it, so we always do a base tune without meth first. Then we do our meth tuning.”
Once Matt got a handle on our combination, he sent it to us in California and we uploaded the resulting calibration to the factory PCM with an SCT X4 handheld device before hitting the Dynojet.
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.

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