Premium or Regular Gas - Which Works Best In the Ford Bronco Sport?

What fuel to use in a given vehicle is a very popular forum topic. While there are vehicles that we test that REQUIRE premium fuel, nearly all that mention premium fuel at all only RECOMMEND it. The Ford Bronco Sport, with its efficient and powerful turbocharged EcoBoost engines, falls into the latter category. Ford does list the performance specs of the Bronco Sport with numbers derived when using premium fuel, but premium fuel is not required. That begs the question, what is the benefit?

We certainly know the downside of using premium fuel. Cost. Here in our Metro Boston testing area, premium fuel can cost as much as 25% more than regular. That means about a buck more per gallon in some stations. The EPA says that the average annual fuel cost of the Bronco Sport Badlands is $2,500 per year using regular fuel. We did some quick math and calculated that using premium gas instead of regular would cost an owner about $13,000 more over the vehicle's 20-year lifespan. 

Here is what Ford says in the owner’s manual about fuel for the Bronco Sport: 
“Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some fuel stations, particularly those in high-altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle warranty. For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.”

What Do Experts Say About Using Premium Fuel?
Both AAA and Consumer Reports have conducted tests on mainstream vehicles to see if any benefit was derived from using premium fuel. Both determined, with high certainty, that in vehicles where premium is not REQUIRED, using premium fuel is a total waste of money. Our links can take you to their stories summarizing these findings. 

Bronco Sport Premium Fuel Test - How We Did It
We decided to run our own long-term tester, a Bronco Sport Badlands with the 2.0-liter EcoBoost Engine, on 87-octane regular fuel for a while and record our mileage. Over more than 1,000 miles, we observed 25.3 miles per gallon. We had previously compared the MPG average display in the vehicle to the calculations we made by dividing miles traveled by gas put into the vehicle and found them to be very close, within about 0.4 MPG. 

We ran the Bronco Sport down to the “Low Fuel” warning light, which comes on at about 50 miles of range remaining, and then filled up with 93 octane premium fuel. We zeroed the trip odometer and then drove the vehicle until the low fuel warning light illuminated again. This took place over a couple of weeks, during which time we did the same type of driving to the same destinations as we had done previously. 

When we concluded the premium tank test, we recorded an MPG number of 24.7 MPG. So, based on this one tank of fuel, adding premium rather than regular certainly did not improve our fuel efficiency or fuel economy. Rather, both dropped. The efficiency went down just a smidge, but our fuel economy was much, much worse due to the dramatically higher cost for premium. There was no benefit to adding the pricey premium from a financial standpoint. 

About Tire Pressures
I was very careful to check the tire pressures during my testing time with the Bronco Sport. I added 1 PSI to the tires before the premium test since the temps had dropped by about 10 degrees. All of my testing was done with the tires set when cold to 33 PSI, as recommended by Ford. 

Oh, But The Added (Imaginary) Extra Power!
Your author has been testing automobiles for over 11 years. Each week, I’m lucky enough to get a new vehicle for testing, and I review cars here and at Car Talk. In the past, I’ve worked for about a dozen publications. Suffice it to say I know how to test and then report on the feeling I get when I test a vehicle. Based on my testing of the Bronco Sport using premium fuel, there is zero added power felt in Normal mode and zero added power felt in Sport mode. This subjective opinion correlates with what AAA and Consumer Reports found in their objective tests.

To see if the premium fuel would matter, I drove as high as 2,000 feet above sea level in the hills of New Hampshire. I found no difference after adding the premium fuel when accelerating from a stop or when using full power in other scenarios, such as entering the highway via an on-ramp or when legally passing another vehicle on an open stretch of two-lane road. 

One reason it is easy to say that the premium was wasted from a performance standpoint in the Bronco Sport Badlands is that the vehicle has an abundance of power. So much so that it torque steers pretty noticeably when one accelerates and turns at the same time. The Bronco Sport Badlands can barely put the power down without chirping and scrubbing the Falken WildPeak A/T Tires. It doesn’t light up the tires in a smoky burnout like a Hellcat might, but you can definitely feel the wheels at the edge of their grip when you hammer the throttle. 

What About Ford’s Suggestions?
Ford specifically lists hot weather and towing as scenarios where one may feel a difference between regular and premium fuel. Unfortunately, it was in the 60F range for most of my testing, and I did not have the opportunity to tow. Towing does impact fuel economy quite a bit, so any test of that sort would have to be very specific, which is not easy to do because of environmental and traffic differences during test runs. 

Conclusion - Ford Bronco Sport Premium Fuel vs. Regular Fuel Test
As a recovering mechanical engineer, it is hard for me not to try to think up reasons why premium fuel might help make a mainstream vehicle driven on public roads have better fuel economy or better acceleration performance. I honestly cannot come up with anything that convinces me that a modern vehicle equipped with a modern knock sensor and electronic ignition would benefit from 93-octane fuel. 93 is a bigger number than 87, but that doesn’t mean premium makes the car run faster or longer. I’m also aware that race-tuned cars do use high-octane fuel. But the Bronco Sport is not a racecar. 

Horsepower ratings for cars are, unfortunately, a necessary evil started by enthusiast car magazines long ago. Referring to “horsepower” is a hard habit to break. When we refer to horsepower today, what we really mean is the peak horsepower. The Bronco Sport has 250 hp, but that is at 5,500 RPM. No Bronco Sport owner spends much time driving around at 5,500 RPM. At the 1,500 to 3,500 RPM we spend most of our driving time, the vehicle uses dramatically less than 250 hp. Perhaps 20 to 30% of its peak power is in use during most of our normal driving. This is one reason why any tiny gains in power are not felt. If you want more power, you push the go pedal, the vehicle downshifts, and the revs build. The vehicle gives you more of that power you are seeking. Perhaps 50 to 60% of max power. And if you do redline the vehicle, it quickly shifts to the next higher gear. 

This would be a better story if we recorded a fuel efficiency gain or if we could honestly say that one can sense the “added power,” but neither is the case. If you have had better luck using premium, we don’t dispute your results, but based on our testing, we concur with what AAA and Consumer Reports have found. Premium fuel in a vehicle that is rated for 87 octane fuel is a big waste of money. 

Fun Footnote: When I was fresh out of college, I worked at a pump company that also built fuel skids and supplied sensors, meters, and instrumentation for fuel depots. A senior engineer took me to a Massachusetts depot where the three octane blends (87, 89, 93) are created from 87 and 93. Our equipment was used to meter and control the mixing of the two fuels, and we went out to calibrate it. I asked him if the 93-octane fuel had some pricey additive that made it so much more expensive, and he just laughed and shook his head. 

Images by John Goreham. Bronco Sport MPG chart courtesy of the EPA.

John Goreham is an experienced New England Motor Press Association member and expert vehicle tester. John completed an engineering program with a focus on electric vehicles, followed by two decades of work in high-tech, biopharma, and the automotive supply chain before becoming a news contributor. In addition to his eleven years of work at Torque News, John has published thousands of articles and reviews at American news outlets. He is known for offering unfiltered opinions on vehicle topics. You can follow John on Twitter, and connect with him at Linkedin.