KJ Jones
Brand Manager, 5.0 Mustang & Super Fords
December 1, 2009
Photos By: Anderson Ford Motorsport

Despite our current race-car project (Boss 340) and our never-ending interest in late-model Mustangs that are used for drag racing, autocross/road racing, drifting, or whatever form of closed-course automotive competition, it's street performance that will always be at the top of our list of primary interests when it comes to modified Ponies.

Let's face facts: There are a lot more Fox ('79-'93), SN-95 ('94-'98), New Edge ('99-'04), S197 ('05-'09), and now SN-10 ('10) Mustangs rolling along the world's roads and highways than there are on the racing circuits, and keeping up with the latest info on ways of improving daily driven 'Stangs is the main reason why we do what we do here at 5.0 Mustang & Super Fords.

In most cases, installing parts that are intended to take a Mustang's 5.0-, 4.6-, or 5.4-liter engine beyond its stock performance parameters is the main objective of our tech efforts. However, simply evaluating bolt-on parts is not the plan this time.

In lieu of covering an install, we're looking at the mixture of 85 percent ethanol and gasoline, the alternative fuel better known as E85 (or "corn," if you're Dan Schoneck, one of our King of the Street regulars who swears by the stuff). We attempt to reduce the difference between miles-per-gallon with gasoline and miles-per-gallon using E85, and increase performance (rear-wheel horsepower/torque) with the 105-octane corn.

The idea for this project came about as a result of our nation's fuel crunch back in 2008, when prices for premium gasoline (91-93 octane) soared above $4 a gallon from coast to coast, and actually forced many enthusiasts to park their V-8-powered, and in some cases, modified Mustangs simply because the cars were too expensive to drive on a daily basis.

Assistant Director of State Legislation for the Illinois Farm Bureau-and avid 'Stang enthusiast-Paul Cope is a strong supporter of using renewable fuels in vehicles. Corn is a major crop in the Land of Lincoln, and it's the primary source material used for producing ethanol fuel.

With this being the case, we think it's only appropriate that Paul's bone-stock '04 Mach 1 be used for our study on mileage and performance differences between E85 and gas. We hope the test results will show fellow Mustang enthusiasts the simplicity and potential financial benefit of making the change to corn.

Typically, vehicles using E85 can get anywhere from 20 to 30 percent less mileage than those with engines that run on regular gasoline. However, we believe that simply through tuning, the naturally aspirated 4.6-liter engine in Paul's Mach actually can be made stronger and much more efficient with E85.

The dyno-test portion of our test was conducted inside the power chamber at Anderson Ford Motorsport in Clinton, Illinois. Any tuning (on a Dynojet chassis dyno) that takes place inside the cell is usually handled by Rick Anderson and Danny Biggs. However, for this project, Andy Wicks, of DynoTune in Watertown, South Dakota, made the trip to Clinton and created DiabloSport PCM calibrations for our test Pony that allow it to run on premium gasoline or 105-octane ethanol.

Paul, Chuck Spencer, Rick, and Andy all believe a Mustang's computer can be programmed to improve fuel economy (from a cost perspective), and take advantage of its high octane and good combustion properties for more power when the engine is burning E85. We give it a try to find out if it can using the Mach 1's factory tune, as well as Andy's 93-octane and E85 performance tunes. As always, the details on what we find are the reason you should keep reading.

Due to the subject and tests that were performed for this project, this report is a lot more chart-and-data-intense than our usual tech stories. We strongly recommend you pay close attention to the details, as they may lead you to consider going with E85 the next time you fill your 'Stang's tank!

Mileage Breakdown
This certainly is a lot of data to digest, and we totally understand if you're asking yourself what all this means.

Basically, while the performance benefits of E85's 105 octane are well documented (note our horsepower and torque gains in the On the Dyno sidebar), the downside, if you will, of using corn is an inherent 28-30 percent loss in fuel mileage. As you see in the charts, our tests with E85 and tuning resulted in a much smaller mileage loss (7-10 percent) for Paul Cope's '04 Mach 1.

Our data reflects the benefit of filling up with E85 when the price difference is narrow, especially as the country continues to pull itself out of an economic slump. Depending on the market, there sometimes is only a 30-cent difference between premium gasoline and E85. (As of this writing, current fuel prices in Central Illinois are $2.83 for premium gas and $2.39 for E85).

As an advocate of using alternative fuel sources in passenger vehicles, Paul has a message for Mustang enthusiasts: "Don't think one-dimensionally, and don't bail on E85. Flexible fuel is better for the environment; at the same time, its higher octane promotes more horsepower in naturally aspirated and power-adder-assisted engines. We've shown that the normal mileage loss using E85 can be significantly narrowed with proper tuning. From an economical perspective, a great benefit is that with E85 you're using with a home-grown product, which means money is staying in the U.S., not going overseas."

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City Mileage-Factory Tune-Premium Fuel
DateTempStartStopEndODO BeginningODO EndingMiles
10/16/0766°HudsonBloomingtonHudson37,043.937,077.633.7
10/17/0777°HudsonBloomingtonHudson37,077.637,126.348.7
10/18/0778°HudsonBloomingtonHudson37,126.337,145.619.3
10/23/0763°HudsonBloomingtonHudson37,145.637,172.526.9
10/24/0757°HudsonBloomingtonHudson37,172.537,210.538.0
10/29/0760°HudsonBloomingtonHudson37,210.537,232.321.8
10/30/0760°HudsonBloomingtonHudson37,232.337,252.320.0
11/06/0759°HudsonBloomingtonHudson37,252.337,271.519.2
11/13/0766°HudsonBloomington37,271.537,284.112.6
Fuel: Shell 93 octane
Total Miles Traveled: 240.2
Total Fuel Used: 14.088
Average City Fuel Economy: 17.05
Price of Premium Fuel: $4.299/gal
Cost Per Mile: $0.25
Highway Mileage-Diablosport 93 Tune-Premium Fuel
DateTempStartEndODO BeginningODO EndingMiles
05/07/08 thru 05/08/0869°HudsonSpringfield38,386.838,698.5311.7
Fuel: Shell 93 octane
Total Miles Traveled: 311.7
Total Fuel Used: 12.459
Average Highway Fuel Economy: 25.02
Price of Premium Fuel: $4.299/gal
Cost Per Mile: $0.17

2004 Ford Mustang Mach I
Highway Mileage-Factory Tune-Premium Fuel
DateTempStartStopEndODO BeginningODO EndingMiles
10/11/0760°Bloomington SpringfieldHudson36,727.836,876.9149.1
10/12/0760°Hudson SpringfieldHudson36,876.937,043.9167
Fuel: Shell 93 octane
Total Miles Traveled: 316.1
Total Fuel Used: 14.147 gallons
Average Highway Fuel Economy: 22.34
Price of Premium Fuel: $4.299/ga
Cost Per Mile: $0.19

Highway Mileage-E85
DateTempStartEndODO BeginningODO EndingMiles
5/26/08 thru 5/27/0877°HudsonSpringfield38,832.839,115.2282.4
Fuel: FS-E85
Total Miles Traveled: 282.4
Total Fuel Used: 14.112
Average Highway Fuel Economy: 20.01
Price of E85 Fuel: $3.699/gal
Cost Per Mile: $0.18
City Mileage-E85
DateTempStartEndODO BeginningODO EndingMiles
6/2/08 thru 6/18/0881°HudsonBloomington39,185.639,407.0221.4
Fuel: FS-E85
Total Miles Traveled: 221.4
Total Fuel Used: 13.895
Average City Fuel Economy: 15.93
Price of E85 Fuel: $3.699/gal
Cost Per Mile: $0.23
City Mileage-Diablosport 93 Tune- Premium Fuel
DateTempStartEndODO BeginningODO EndingMiles
6/20/08 thru 7/2/0885°HudsonBloomington39,407.039,680.7273.7
Fuel: Shell 93 octane
Total Miles Traveled: 273.7
Total Fuel Used: 14.197
Average City Fuel Economy: 19.28
Price of Premium Fuel: $4.469/gal
Cost Per Mile: $0.23

On The Dyno
Our off-road testing was done on the Dynojet chassis dyno at Anderson Ford. Andy Wicks of DynoTune (Watertown, South Dakota) worked with Rick Anderson and Danny Biggs, to determine the effect of E85 on Paul Cope's '04 Mach 1, from a performance perspective.

As expected, E85's 12 additional octane (over premium pump gas) opened our test Pony's performance window considerably. We saw nearly 30 peak horsepower and almost 40 additional lb-ft of torque gained at the feet. Andy's DiabloSport ethanol tune kept the air/fuel mixture within close range of the 'Stang's 14.6 average mixture on gasoline.

93 OctaneE85Difference
RPMPowerTorqueA/FPowerTorqueA/FPowerTorqueA/F
3,000141.45247.6413.24147.44258.1314.695.9910.491.45
3,100146.62248.4113.20153.26259.6614.806.6411.251.60
3,200152.32249.9913.13160.08262.7314.747.7612.741.61
3,300160.01254.6613.01167.99267.3614.577.9812.701.56
3,400169.54261.8912.90179.59277.4014.4510.0515.511.55
3,500176.23264.4512.98191.57287.4714.4415.3423.021.46
3,600181.63264.9913.06199.90291.6514.4318.2726.661.37
3,700185.14262.8112.95205.98292.3914.1820.8429.581.23
3,800190.76263.6512.89212.67293.9313.9521.9130.281.06
3,900196.39264.4712.98221.13297.7913.8424.7433.320.86
4,000202.75266.2112.96230.69302.8913.7727.9436.680.81
4,100211.47270.9012.86241.33309.1413.6629.8638.240.80
4,200220.11275.2512.64248.81311.1413.4328.7035.890.79
4,300223.72273.2612.60252.35308.2213.3128.6334.960.71
4,400227.67271.7612.78256.43306.0913.4628.7634.330.68
4,500231.60270.3112.83259.92303.3613.5828.3233.050.75
4,600236.97270.5712.82264.60302.1113.4327.6331.540.61
4,700245.54274.3912.94271.66303.5713.3726.1229.180.43
4,800250.84274.4613.05278.20304.4013.2827.3629.940.23
4,900257.60276.1113.02282.55302.8513.2524.9526.740.23
5,000261.26274.4312.99285.30299.6913.1224.0425.260.13
5,100263.40271.2612.95284.66293.1613.0121.2621.900.06
5,200262.68265.3112.95285.33288.1912.8322.6522.88-0.12
5,300262.45260.0812.96283.29280.7412.7220.8420.66-0.24
5,400258.94251.8513.01280.81273.1212.7521.8721.27-0.26
5,500260.52248.7813.03280.88268.2212.7520.3619.44-0.28
5,600261.84245.5813.04282.69265.1312.7620.8519.55-0.28
5,700263.60242.8913.07283.81261.5112.6920.2118.62-0.38
5,800262.03237.2813.07285.30258.3512.7323.2721.07-0.34
5,900258.43230.0613.11286.43254.9712.8228.0024.91-0.29
6,000258.36226.1613.03286.34250.6512.9227.9824.49-0.11
6,1000.000.000.00285.28245.6313.09285.28245.6313.09
6,2000.000.000.00282.39239.2213.15282.39239.2213.15
6,3000.000.000.00277.80231.6013.31277.80231.6013.31