I had a thought as my low fuel reminder light came on this morning. Since the owners manual states that regular 87 unleaded is fine, but premium 91+ unleaded yields the highest performance, would that also mean that premium unleaded will yield the best fuel economy ?

I decided to try a little experiment and filled up from empty (22 miles to empty) with Premium 93 octane to find out. As I was filling up, I was crunching the numbers in my head, and here it what I've come up with...

Regular at the Valero station was $3.70, premium was $4.00. That means that it would cost $96.20 to fill up on regular and $104.00 on premium from dead empty. That is a difference of $7.80 per tank. I then figured the break even point of fuel efficiency vs the extra cost of premium. I used my current 15.0mpg on regular unleaded as a baseline. My equation is this:

$7.80/$3.70= 2.11 (means that price difference would've afforded me an extra 2.11 gallons of regular unleaded)

2.11 gallans of regular of unleaded (x) 15mpg= 31.62 miles

31.62 miles/26 gallon tank =1.22 mpg improvement needed from premium fuel to breakeven on additional cost per gallon.

To summarize, if im getting 15mpg on regular 87 gas, then i need to get at least a 1.22mpg gain (16.22mpg) on premium to make up for higher cost per gallon. Anything over 16.22mpg would make premium gas more cost effective than regular unleaded, in which case, you're better off to continue filling up with premium.

Oh, and the added performance is a plus too!

I'll let you know my findings when i run the tank out in a few days...

Anyone already done a similar experiment?

 

I'd be interested in the results.I still have 3/4 of a tank left from the free fill up from when I bought my truck. So I won't be able to try premium for a while.
Do you notice much difference in performance with premium fuel?

 

So far I've only driven a couple of miles with the premium in the tank, so no noticeable difference in performance yet... I did notice that it seemed to be a bit smoother at idle, however.

 

Try Conoco, Chevron or Shell which are all easy to find in most TX cities. I run Conoco when in TX and I always gain 2 mpg over Shell in AR. If I use Valero in any of my vehicles; they knock, run sluggish and receive poor mileage. There are better brands of gasoline. I would run 3 tank fulls of a different brand and see what happens.

Good luck.

 

Filling the 36 gallon tank hurts so 87 is for me!

 

haha, ya. That'd be 138 bucks with premium!

My 09 had the 36 gal tank...it did hurt but I could go almost a month before having to fill up

I kind of miss the big tank.

 

I'd be curious to see if you pick up any MPG, but i don't see if happening

 

15 mpg, is that completely stock? i'm getting 16-16.5 with my 5.0 in the city.

 

His mileage seems low, my last fill up was mostly freeway and was 19.99 mpg

 

Ha, I got a weird one for you, I get 20 in the city and 18 on the highway. Explain that one to me, was taking the expressway but switched to the back streets because of the better mileage.

I am excited let us know how it goes. I read you gain an extra 15 HP and 15 Torq when using premium on the ecoboost, but you have to run a few tanks through it for the computer to adjust. Read it on the internet so it could all be lies but will be interesting.

 

i've noticed the same thing. i can get 16 city all day long, but jump on the highway and it is a hit or miss if my mileage will increase or stay the same.

are you 2 or 4wd?

 

There should not be much of a difference in economy from brand to brand, as all brands are supplied by the same suppliers/refineries (mainly corpus christi/houston for san antonio area)...The difference comes with the detergents additives that shouldnt have any effect on the performance of the gasoline itself.

Years ago the differences in brands were great, but due to stringent government standards and open market practices, really all gas is good and pretty much the same... That said, I'd look more at the station itself. My geologist buddy of mine does alot of work with the underground storage tanks at pump stations, and he says that many tanks are poorly designed, installed, and maintained. Bad tanks can produce excess condensation (water), deposits, and outside contamination, thus, hindering the properties of the gas.

Just my 2 cents

 

My truck is completely stock with right at 1000 miles. I do get to hit some city traffic twice a day, so that's where my 15mpg comes from... I get between 19-22mpg at 75mph on hwy depending on the prevailing wind. I've noticed the ecoboost is more sensitive to winds than my 09 5.4L.

It is 4WD with 3.55 LS rear end.

 

I'm jealous...I can't get better than 13-14mpg on the highway with my ecoboost at 70mph. 4x4 crew cab, 4.10 gears on 33" MT's...so far from the best setup for mileage, but not near what I expected.

 

How fast are you driving on the freeway? And what kind of gears do you have?