KJ Jones Senior Technical Editor
January 1, 2010

Despite the hope and optimism for our nation to make a strong economic recovery at some point in the near future, the truth of the matter is that many of us still have penny-pinching lives right now. There's absolutely nothing wrong with plugging a tighter notch on our fiscal belts for the sake of the economy. However, for those who live and die by going out and buying the latest, greatest whiz-bang gear for their 'Stangs, the no-spending handcuffs sometimes feel like they're taking our wrists completely off!

Now, on the other side of the want-versus-need spectrum, an automotive product we really can't do without is fuel-more specifically, pump gasoline comes to the forefront as the single most important commodity that 'Stangbangers have to spend their dough on (no matter how high the price). Car owners have been seeking plausible methods for saving money at the pump. However, the catch-22 is that stepping down to 87-octane means performance generally suffers. This is especially true of the Three-Valve, 4.6-liter V-8s that are found under the hood of '05-present Mustang GTs, as they are tuned to take advantage of octane.

What if you could burn your 87-octane fuel and have your performance too?

When it comes to late-model Mustangs (and even pre-'05 ponies, for that matter), Matt Snow definitely knows a thing or two about gaining performance, not losing it. Matt's company, Snow Performance, makes the popular and effective Boost Cooler water-methanol-injection systems that (when combined with California's 91-octane pump gas) help create more horsepower and torque by increasing the weak fuel's octane, thus allowing for more timing advance, as well as by cooling the charge of turbo- or blower-boosted air. Lowering the temperature of the air charge slows the burn rate of an engine's air/fuel mixture, and ultimately makes using higher boost on pump gas possible without fear of experiencing engine-damaging detonation.

With all that said, you're probably wondering what role, if any, water-meth can play in the fuel-economy equation. Matt wondered the same thing and conducted a study to determine just that, using a naturally aspirated '07 Mustang Shelby GT. His primary mission for the test was to create a way to achieve maximum power through aggressive timing, with 87-octane, regular-unleaded pump gas and see if it's possible to save at least $0.20 per gallon. He conducted his research using 91-octane premium for baseline, and also the less-expensive, regular-unleaded petro. It included capturing not only performance data, but fuel-mileage details delivered by Snow's all-new MPG-MAX G Boost Cooler (PN 20150; $699) on both the dyno's rollers and in real-world road testing.

Matt and engineers at Snow Performance developed a water-meth kit for naturally aspirated and boosted gas engines that relies on an all-new fuel-injector-referenced injection-management controller, which activates a small, steady spray of water-methanol that covers the entire power curve. The controlled water-meth shot increases the efficiency of the combustion process, and therefore promotes more power without requiring additional fuel that normally would act as a cooling agent. The increased efficiency yields improved fuel economy. However, on the power side of the equation, the MPG-MAX G system also includes an independently mapped, fully adjustable second stage of water-meth injection. The second hit uses a larger (orifice size) nozzle to inject more fluid and make more power.

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The accompanying photos and captions provide an overview of Derek Linscott's expert installation of a Snow Performance MPG-MAX G Boost Cooler on the aforementioned '07 Shelby GT. Outfitting the system on an S197 Mustang is a straightforward endeavor that can be performed at home in the driveway or garage. Dyno tuning is required, of course, and we say thanks to Precision Dyno of Colorado Springs, Colorado, for its assistance with installing the water-meth kit and all of the extensive testing that was performed once it was on the 'Stang.

On The Dyno...And The Road
Dyno tests were performed first with the test '07 Shelby GT Mustang's PCM loaded with its stock tune and 91-octane premium-unleaded fuel in the tank, and then with Ben Fox's SCT tune in the processor, regular-unleaded 87-octane gasoline, and Snow Performance's water-methanol injection.

A total of six stock versus MPG-MAX G tests were done back-to-back to minimize uncontrolled variables, with Precision Dyno's SuperFlow chassis dyno operating on its "road-load test" setting. The test Mustang was driven on the rollers for the equivalent of 10 miles at a steady 75 mph (the dyno uses the 'Stang's frontal area to calculate wind resistance). The engine's coolant temperature, intake-air temperature, and fuel-tank temperature all were normalized at the start of each test.

As you see on the charts that accompany this report, with the water-methanol injection and SCT tune, the Shelby experienced a (calculated) gain of 1.6 miles-per-gallon (0.8 mpg on vehicle readout) with 87-octane fuel during the dyno evaluation. On the street using a 16.64-mile loop (70 percent highway, 30 percent surface streets), Matt saw 0.6 additional miles-per-gallon (0.4 on the vehicle readout).

While gas prices vary from state-to-state and we're currently experiencing somewhat lower prices for higher-grade fuel, it's nice to know there is a plausible solution for making better mileage without suffering a devastating performance hit. The Snow Performance MPG-MAX G Boost Cooler system definitely will make your wallet happier when the price of fuel rises.

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Fuel Economy Dyno Test
Run 135Avg. Stock
Engine Coolant Temp (F) 162.0° 160.9° 146.0°
Fuel Tank Temp (F) 65.7° 68.0° 68.6°
Stock or Water-Methanol Stock Stock Stock
Fuel Can Weight (pounds)Before35.00 27.85 21.02
After31.40 24.10 17.89
Fuel Used (pounds) 3.60 3.75 3.13
Fuel Temp (F) 62.7° 62.9° 63.0°
Fuel Specific Gravity (g/ml) 0.739 0.739 0.739
Fuel Used (ml) 2,210 2,302 1,920
Fuel Used (gal) 0.58 0.61 0.51
MPG Calculated 17.2 16.4 19.617.7
MPG In-Car Info 19.5 20.0 20.119.9
Water-Methanol Used (ounces) NA NA NA

Run246AVG. W-M
Engine Coolant Temp (F)159.1°154.2°162.2°
Fuel Tank Temp (F)68.0°70.5°71.9°
Stock or Water-MethanolW-MW-MW-M
Fuel Can Weight (pounds)Before31.4024.1017.89
Fuel Used (pounds)3.553.083.01
Fuel Temp (F)62.7°63.0°63.2°
Fuel Specific Gravity (g/ml)0.7390.7390.739
Fuel Used (ml)2,1791,8901,847
Fuel Used (gal)0.570.500.49
MPG Calculated17.520.020.419.3
MPG In-Car Info20.421.120.620.7
Water-Methanol Used (ounces)101010

Fuel Economy Road Test
Run13AVG. Stock
Stock or Water-MethanolStockStock
Fuel Can Weight (pounds)Before36.1024.44
Fuel Used (pounds)5.965.90
Fuel Temp (F)56.0°62.1
Fuel Specific Gravity (g/ml)0.7390.739
Fuel Used (ml)3,6573,621
Fuel Used (gal)0.970.96
MPG Calculated17.217.317.3
MPG In-Car Info18.919.019
Water-Methanol Used (ounces)NANA
Stock or Water-MethanolW-MW-M
Fuel Can Weight (pounds)Before30.1418.54
Fuel Used (pounds)5.705.82
Fuel Temp (F)59.562.5
Fuel Specific Gravity (g/ml)0.7390.739
Fuel Used (ml)3,4983,572
Fuel Used (gal)0.920.94
MPG Calculated18.117.717.9
MPG In-Car Info19.619.219.4
Water-Methanol Used (ounces)1213

A total of six Stock versus MPG-MAX G tests were done back-to-back to minimize uncontrolled variables, with Precision Dyno's SuperFlow chassis dyno operating on its "road-load test" setting