2.7 Ecoboost vs 3.5 Ecoboost fuel economy

I’m looking to buy a new truck and have narrowed it down to either the 2.7L or 3.5L EcoBoost engines. My commute is about 40 miles each way, averaging around 45 mph. From what I’ve read, the 2.7L seems to get better gas mileage in real-world driving compared to the 3.5L. Although the fuel economy ratings on the stickers are close, people report getting over 20 mpg with the 2.7L and around 17 mpg with the 3.5L, which is surprising since the 3.5L is rated for 17 mpg in the city.

Does anyone have experience with the 3.5L’s fuel economy on flat highways at 70 mph (in a crew cab 4x4 with a 5.5 ft bed)? I’m thinking the 2.7L might be better, but I’m curious if there’s really not much difference in mpg between the two.

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If you don’t tow or haul heavy loads, the 2.7L will give you better gas mileage. If you mainly use the truck for daily driving, go with the 2.7L. You didn’t mention the 5.0L, but I was getting around 19-20 mpg until winter. It sounds great with a Corsa exhaust. However, my truck has issues with burning oil, so when I switch, I’ll be going for the 3.5L.

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I see you have a Super Duty with the 6.7 engine. Have you been having problems with it?

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I have the 3.5L EcoBoost (supercrew, 4x4, 6.5’ bed), and my average fuel economy over 34,000 miles is 18.3 mpg.

In winter, I get about 17 mpg in town and around 20 mpg on flat highways at 70 mph. In summer, it’s around 18 mpg in town and 21 mpg on the highway.

I had a 2018 loaner with the 2.7L EcoBoost for a week. It was a supercab XLT with 2WD, so it was lighter than my truck. The 2.7L definitely got better gas mileage, a few mpg more than my 3.5L. It had plenty of power too. The only time I noticed a difference was when driving over 70 mph and accelerating—the 3.5L pulled harder, but that’s expected. That said, the 2.7L wasn’t slow, and around town, I probably wouldn’t notice much difference between the two engines.

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Thanks for the info! This is exactly what I’m looking for from owners with these engines.

Your gas mileage seems pretty good overall.

Here’s what Fuelly shows for averages with the 2018 3.5 EcoBoost: 2018 Ford F-150 MPG - Actual MPG from 312 2018 Ford F-150 owners.

You can see that some people get 12-13 mpg, while others get 18+ mpg. I guess these engines can vary a lot depending on how people drive and tow.

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My gas mileage is decent, but that’s because I pay attention to how I drive. The Fuelly data shows a bell curve, so once you ignore the outliers (like hypermilers, hotrodders, and those who idle or warm up a lot), you’ll likely see an average of 16-18 mpg with the 3.5L EcoBoost. Adjust that based on how you drive. If you’re more conservative and don’t use long remote starts, you’ll probably be on the higher side. If you idle a lot, use remote starts, or take short trips, you’ll likely be on the lower side. Living in the south probably helps my mileage due to warmer temperatures.

When comparing the 3.5L to the 2.7L EcoBoost, the 3.5L’s most common averages are 16-19 mpg, while the 2.7L’s are 17-21 mpg. That suggests the 2.7L gets about 1-2 mpg more on average, which is roughly 5-10% better. The 3.5L is also more expensive, so the 2.7L could save you some money too.

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Whether you choose the 2.7 or the 3.5, if you drive aggressively, your gas mileage will drop more than it would with a naturally aspirated engine.

No, I actually sold that over a year ago. Now I have a 2018 F-150 with the 5.0L engine, and it’s causing me more trouble than all my previous 25 Ford trucks combined.

I want to add a couple more points. I regularly drive both the 2.7L and 3.5L EcoBoost, and they’re very similar. The 3.5L is definitely stronger, with slightly lower MPG. One noticeable difference is in engine braking. The 2.7L is almost useless when it comes to engine braking, while the 3.5L is better but still not great. When off-roading, the 3.5L in 4L does a good job controlling your speed on steep downhill slopes. The 2.7L, on the other hand, feels like you’re in neutral—it really surprised me the first time I experienced it.

Hi, I’m new here. I have a 2016 F-150 with the 2.7L engine, and I love it. I drive 30 miles each way on the highway every day and get over 20 mpg. On long trips, I’ve gotten as high as 23 mpg. It has plenty of power.