F-150 Ecoboost 87 octane versus 91 octane.

[ROBERTSUNRUS]

Hi, for those who own an F-150 Ecoboost, have you tried running 91 octane fuel, and was there any difference in power and gas mileage that you can tell? Is anyone running 91 octane premium fuel only and why? Or do you only run 91 octane premium fuel when towing?

Note: So far, I have only run 87 octane, and still haven't towed yet.

[richinny]

i've run both. at 30 cents a gallon difference the cost factor is a break even. lately the spread seems to be close to 40 cents. the power/performance is noticeable and i feel the extra money is worth it. it is noteworthy to mention my trailer when fully loaded scales around 9400 lbs. and i have 6 tires to keep rolling on the trailer. while I81 on the east coast isn't flat it is flatter than out west.

if i want to micromanage my fuel, when i'm fuel before hooking up i try to have a pretty dry tank and when i fill for the last leg of my trip i'll add just enough premium to get the trailer dropped off. since i tend to follow the interstates i tend to take the fuel level pretty low and when the pump kicks off at $100 i'll fill the last few gallons with 87 or 89 octane.