MRigs81

Okay, guys. Lets take a poll and see what you think is the best octane for the 3.5 under normal driving conditions.

I know the owner's manual states 87 or higher but who sees a difference between Regular vs Premium? I have used both so far and can't notice a difference in power or efficiency.

I am a little surprised that Ford doesn't recommend 91+ octane for these motors. Most turbocharged cars require premium. My 2003 SVT Focus (naturally aspirated) required premium fuel. My dad drove it once and made the mistake of putting 87 in it to refuel. It never ran worse than the next 150mi until I topped it off with premium again and cycled that through to be able to replace it all with 93.

nailsnails6969

When running with no load, I also see no noticeable difference between 87 and 91 octane. Both with no alcohol.

With a loaded enclosed trailer behind the truck, I can see a small difference in performance and fuel economy with 91 being slightly better.

The big surprise came when I noticed that I was almost out of my 91 octane no ethanol, while pulling the trailer down the interstate at 68mph. I pulled off the highway and refilled with the only thing they had left, which was 89 octane 10% ethanol. Everything had been going well on the 91. No downshifts and averaging about 14mpg. Within 5 minutes of refilling with the 89 octane 10% ethanol, the truck would barely stay in 6th gear. My economy dropped to roughly 10mpg too. That made the rest of my 120 miles a little annoying. When I unhooked the trailer, it went back to me barely noticing a difference between the 89 10%e and 87 or 91 no ethanol.

I typically run 87 no ethanol, except when I know I will be taking a long trip with a heavy load. Then I use 91 no ethanol, mostly to help eek out the tiny bit better mpg.

MRigs81

That's what I was looking to hear. I normally use 87 because I don't notice a difference. When I plan to do longer, heavier hauling I will use premium. That's interesting about the 10% ethanol though. Inside the fuel door it states that you can use up to 10%. I avoid ethanol at all costs though.

Toproller

Have had my 2012 Eco for 2 months, no hauling, just my DD. Performance wise, I have seen no differance between reguler and premium, mpg though is 2 mpg higher on average with premium.

SkiSmuggs

Interesting. I use 89 in summer to prevent detonation while climbing mountain grades except to fill on 93 when planning a tow. I've tried 91-93 on long (800 mile) trips and saw no improvement in mpg over 89. And I run 87 in winter as heat is not a problem and I don't tow then. However, your 2 mpg improvement certainly justifies the cost.

Razorback150

The only difference I noticed was last summer when it was around 100F, it ran better and got better MPG (about 1.5-2.5mpg better) with 91-93 oct. Other than that, no difference.

acadianbob

I feel that I get 1 to 1.5 mpg better on premium. I use premium all of the time now. It pays for itself.

08Darkness

Agreed. I see about a 1.5 mpg gain and I feel it's worth the extra you pay per tank.

My train of thought is I really won't miss that extra $5 - $10 a tank. So I might as well run "the good stuff"

Watt-maker

When I purchased my truck around the first of may, the next few fill ups I saw no difference between 87 and 91. However, after driving 7500 miles and add in summer heat and I do now see a difference. MPG is only about 1 better but the truck feels much more responsive. Most of these miles is at 6500 - 7500ft above sea level. I took a trip to ND late last month. Used only 91 and the truck ran great.

troutspinner

92-93 for 12k+ miles. I've tried 87 twice, once while towing and once for a long trip, fuel economy was worse. Throttle response seems better with the good stuff as well.

I think if you weigh out the cost with the improved MPG's, it's definitely worth using the higher octane.