Ford Uses Different Fuels For Different Tests

The 2016 Lincoln MKX crossover utility vehicle fitted with the turbocharged 2.7-liter EcoBoost four-cylinder engine is rated on the company website at 335 horsepower and 380 pound-feet of torque. But wait. What’s that asterisk? Oh, it says those ratings are based on a test performed using 93 octane fuel, even though the vehicle only requires the use of conventional 87 octane gas.

Ethanol free gas boosts fuel economy test numbers

Engine power could be 5–10% lower if tested using ordinary 87 octane fuel because modern engine management systems adjust automatically for different grades of fuel. That’s why a turbocharged engine is able to operate on 87 octane gasoline without harmful detonation inside the engine. Ford does not offer power ratings based on using the lower grade fuel, however.

Just a minor point? Consider this: 93 octane gasoline is not available in some areas of the US, particularly west of the Rocky Mountains and in most of California. It’s also as much as 50 cents a gallon more expensive than conventional 87 octane gasoline.

Also, according to Green Car Reports, when Ford Motor Company tested the MKX to obtain its official EPA fuel economy ratings (21 mpg combined for the front wheel drive only car; 19 mpg combined for the all wheel drive version), it used another fuel not generally available in the US — 87 octane gas with no ethanol added. That fuel is known as E0 or G100 to differentiate it from the increasingly common E10, composed of 10% ethanol and 90% gasoline.

The EPA does try to compensate for differences in fuels. According to the Fuel Economy Testing and Labeling protocol on its website, 

EPA does account for the impact of low-level ethanol blends in our fuel economy estimates. Ethanol has a lower energy density than gasoline—about one-third less energy per gallon.

That means a car operating on 10 percent ethanol would require about 3 percent more fuel to travel one mile than a car operating on gasoline and thus have about 3% lower fuel economy.

EPA currently reduces all fuel economy test values by about 10 percent to account for ethanol in gasoline and other factors such as wind, hills, and road conditions. 

The Agency says, “Later this decade, EPA is phasing in a requirement to change our federal emissions test fuel to include 10 percent ethanol by volume.”

So what is going on here? Is Ford trying to pull a fast one on the public? Not really. Every manufacturer does everything it can to get its power and fuel economy numbers up as high as possible within the limits of the testing protocols it must follow. And after the subject was raised by automotive journalists last week, Ford did move the asterisk pertaining to the MKX power ratings from the bottom of the applicable web page to a spot just below the numbers.

Would any manufacturer deliberately try to cook the numbers? With the EPA and the motoring press watching them like a hawk, they would be an * it.

Steve Hanley

Closely following the transition from internal combustion to electricity. Whether it's cars, trucks, ships, or airplanes, sustainability is the key. Please follow me on Google + and Twitter.