Ford’s EcoBoost engines can run on regular 87-octane gasoline, but premium fuel is required to achieve their maximum advertised output. The difference comes from Ford’s Octane Adjust Ratio system, which changes engine calibration according to the fuel detected in the tank.

Regular gasoline in the United States typically carries an 87-octane rating, while premium fuel generally ranges from 91 to 94 octane. Higher-octane gasoline is commonly recommended for turbocharged, supercharged, and high-compression engines because it provides greater resistance to knock.

Bronco power varies with fuel grade

The effect is clear in the Ford Bronco’s turbocharged EcoBoost engines. With regular fuel, the 2.3-liter four-cylinder is rated at 275 horsepower and 315 pound-feet of torque. Switching to premium raises its output to 300 hp and 325 lb-ft.

The Bronco’s 2.7-liter EcoBoost V6 produces 315 hp and 410 lb-ft on 87-octane gasoline. With premium fuel, those figures increase to 330 hp and 415 lb-ft.

These differences are not limited to official ratings. In a 2019 test, Car and Driver placed a used Ford F-150 with the twin-turbocharged 3.5-liter EcoBoost V6 on a dynamometer. Running on 87-octane fuel, the truck produced 360 horsepower and 463 lb-ft at the wheels.

After the tank was filled with 93-octane gasoline, output increased to 380 hp and 475 lb-ft. The truck’s 0-to-60-mph time improved from 5.9 seconds to 5.3 seconds, while its quarter-mile time fell from 14.5 seconds to 14.0 seconds.

How Ford’s Octane Adjust Ratio works

Ford’s Octane Adjust Ratio system builds on the knock-control technology used in production vehicles. Rather than simply reacting after knock occurs, the system identifies the octane level of the fuel in the tank and adjusts the engine’s calibration.

When premium fuel is detected, the engine can use more advanced ignition timing to increase power and torque. The source also notes that this setting can improve fuel economy and reduce emissions. When lower-octane gasoline is detected, the system pulls timing to help prevent pre-ignition and knock.

That strategy allows EcoBoost owners to move between regular and premium gasoline without risking engine damage. However, using 87-octane fuel means accepting reduced power and responsiveness, along with the possibility of higher fuel consumption compared with premium.

Other Ford engines have different fuel requirements

Ford’s naturally aspirated 5.0-liter Coyote V8 in the Mustang can also operate on 87-octane gasoline. To produce its quoted 480 hp and 415 lb-ft, however, the engine requires 91- or 93-octane fuel.

The supercharged 5.2-liter V8 in the F-150 Raptor R has a stricter requirement. Its owner’s manual specifies fuel with a minimum octane rating of 91. The engine is rated at 720 hp and 640 lb-ft, and unlike the EcoBoost and Mustang Coyote engines discussed above, it is not presented as compatible with regular 87-octane gasoline.