I only have 3600 miles on my 10 GT. Until recently I was averaging 16 mpg I reset the computer on the highway driving to work one morning and now it shows 20 mpg, and that is with mostly city driving. One question a little off topic for you 10 GT owners, I read somewhere that using 91 or greater octane increases hp and torque. So is this true?

 

I have an auto with 1250 miles that is stored 4 months out of the year and have only used 93 octane in it, I even had the dealer put 93 in it when I picked it up. I average about 14-15 city and 23-24 highway keep in mind I have a lot of hills where I live. Total on average shows 16-17 mpg.

 

10,000 miles. 40/60 city/hwy mix (city miles are very slow stop and go traffic). Bama 93 race tune, 2011 w/ 3.55's. Average just over 19mpg. For reference, with similar driving style on a 2009 Hyundai Sonata, I got around 24.5. That car was rated 22/32. Since Mustang is 17/26, I am pretty happy with mileage. I can always make it higher if I want to, but I really don't want to ;-) .

 

My understanding is that the maximum HP is always the same regardless of octane (as long as it is at least 87) but the computer will adjust (advance timing) to give more low-mid range torque with the higher octane, the higher the better. I have tried 93 and 87 in mine and couldn't see a major difference, but that was strictly by feel.

 

Thx Bert, I have filled up with 87 and 93 and I could feel a slight difference between the two. During the winter I am going to stick to 87 and when the weather warms up switch to 93.

 

Nice bell curve shaping up here! I guess I should have provided more room on the low end of the survey, 30+ isn't seeing many data points . . .

 

My loaner GT from the dealer has almost 300 miles on it, and is posting an average of 15.8 MPG. Its an automatic, and gets ridden pretty hard, I'm sure. I wouldn't think you could do much worse than this.

 

Forget miles per gallon guys. How about smiles per gallon

 

I filled up yest. I had 275.5 miles driven. Oh yeah, about 5,600 on my 11. I averaged 23.4 that tank. Best so far on that as well. I get 91 octane. I am blown away with how great my 5.0 gets to the gallon!! I drive pretty not racey, too. Forgot that word.

 

I drive my car to work half the week (carpool wiht a buddy), mostly highway drive between 60-70 mph.

I have been getting between 23-24 MPH regularly with 87 octane. About the same when using 91/93 so with gas prices using 87.

2010 GT Manual
3.73 gears
Drop in K&N
Stillen Exhaust

 

back To The Top

 

Yesterday I drove 110 mi., almost all highway, cruise control set to ~ 72 mph. At the end of the trip, my avg. mpg was 23.3 and it was still slowly increasing while I was on the highway... 24+ mpg, maybe?

 

My '11 GT Coupe has 3.73's and 6 speed manual. I'm averaging about 15 around town and about 23-26 mpg highway, depending on terrain and speed.

The '11 5.0'L's have aggressive deceleration fuel shut off (ADFSO) technology which cuts off fuel flow when you let off the gas. I spoke to a factory rep about this recently and he said you'll get your best fuel economy on the highway by NOT using cruise control because when you go down a slight hill and let off the gas, the ADFSO turns off the gas flow until you give it throttle again. Conversely, on cruise control, when you go down a slight hill, the cruise will apply the brakes to keep speed constant instead of turning off the gas flow. The factory rep assures me that cruise control will net us a few mpg's less on the highway than manually maintaining speed. Cruise control is only a convenience feature - not a gas saving feature anymore.

 

I get 16.5 almost all hardcore city driving.

Ouch.

 

I have 3.55's, 6 speed manual, and I am running 18" Blizzaks all around for winter. I do very little driving withiin the city. The majority of my driving is interstate. I am averaging 24-26 mpg depending on the wind...yesterday we were driving into a 35 mph wind at 75 mph, and I watched the mpg drop to 22. And, I have 7100 miles on the car.

I use the cruise control because of the active enforcement of the speed limit, in the local area.

 

Great poll. It makes me happy to see I'm right with the GT people. 18 mpg GT500

 

2011 GT, 3.73", manual. I've only seen 18mpg at the best. 17 at the worst. I got about 1,300 miles on it. The cars only a few weeks old.

Is it true that goes up as the engine breaks in more?

 

2012 GT, 3.55 rears, MT82, and it's got just under 300 miles on it right now. I got 17.7mpg on my very first tank. I've only filled up once so I don't have any other data points!

 

I'm getting 20 MPG with 50/50 split of city/highway. I've only got about 1200 miles on mine so far, so I'm hoping it'll go up a little bit more. I've also not taken a long freeway trip yet so not sure how that'll be. Not bad for 3.73s I think. Bone stock for now....

 

2011 with Vortech and I get about 11 MPG around town when I try to keep out of the gas pedal. and about 16 MPG highway