So guys what kind of fuel economy are you getting on your V6 Mustang? I use 87 in the car now and wonder if I use 91 will I get better fuel economy? Your thoughts?

 

You didn't notice the few dozen (or more) other threads discussing mileage?

Synopsis: You may get slightly better mileage using higher octane because the PCM can advance the timing more without knocking but the difference is nowhere near enough to cover the extra cost. (i.e. the higher octane fuel costs at least 10% more than regular but you won't gain 10% mileage... more like about half that)

 

I usually get about 22-24 mpg in mines when it was stock and even now that it has a few mods and that's with mixed driving. When I'm running premium I usually get about 2-3 more mpg but I usually don't do that often. Check out the other threads on this also, good insight.

 

I've never seen a significant improvement with any higher octane above 87 with my V6. I currently have 48K on it's odometer. I drive on average about 700 to 800 miles a week. With its 3:31 rear gearing, I see a constant/honest 24.1 to 24.6 average MPG. This did not change when I tried 3 tankfulls of 91 octane.

As stated before, the money spent on the higher octane actually lost me money.

 

2011 V6 - 17MPG

93 Octane - 3:73 Gears + tune and other mods

 

Does anyone run 89 octane?

 

Was going to say, wasn't this exact same thread posted on here just a few days ago???