5.0 - Better fuel economy on regular (non-premium) gas?

[2011MustangGT]

According to Fuel Economy

When using regular gas, the 2011 GT gets 17/26 MPG
When using premium gas, the 2011 GT gets 15/23 MPG

Is this reliable? Aside from saving pennies at the pump, perhaps there's a viable reason to use regular gas... like say if you're going on a road-trip (with plenty of time to empty that low octane gas out and fill her up for fun!).

Should I trust this? Have others noticed this?

LINKS:
Premum Gasoline http://www.fueleconomy.gov/feg/2008car1tablef.jsp?id=30038
Regular Gasoline http://www.fueleconomy.gov/feg/2008car1tablef.jsp?id=30039

 

[1wildGT]

The 17/26 MPG is what they are claiming for a 2011 GT.

The 15/23 is for a supercharged 5.4L GT500.

One link you are showing is for a 5.4L and the other is for a 3.7L. There is no 5.0 premium vs. regular comparison.

I'm only running 87 if they run out of everything else. According to Ford you are giving away HP/TQ that you paid for by running 87:

Regular Fuel: 402 @ 6.500, Premium Fuel: 412 @ 6,500
Regular Fuel: 377@4250, Premium Fuel: 390 @ 4,250

I highly doubt you are going to pick up significantly higher MPG by running regular instead of premium, but yes the car is capable of running it.

 

[Everett]

the knock sensor will retard timing with a lesser quality fuel which costs you power

 

[dhcolesj]

Due to the crappy gas prices I have gone to the midgrade, but I think thats about as far down as I'm going to go. That is unless I'm going to go on a long road trip and will just be doing interstate miles.
However, I did notice that the MPG did go down a little when I did test the Regular grade. I was getting an average of about 19, then switched to regular (85 I think?) and it went to 17. I made sure to do the same kind of driving for both tanks to be fair. (little bit of sporty riding, and mostly easy going Highway and city mix).

 

[1wildGT]

Due to the crappy gas prices I have gone to the midgrade, but I think thats about as far down as I'm going to go. That is unless I'm going to go on a long road trip and will just be doing interstate miles.
However, I did notice that the MPG did go down a little when I did test the Regular grade. I was getting an average of about 19, then switched to regular (85 I think?) and it went to 17. I made sure to do the same kind of driving for both tanks to be fair. (little bit of sporty riding, and mostly easy going Highway and city mix).

Running 85 octane on an 11:1 compression engine is asking for trouble. The minimum recommended octane in the owners manual is 87.

 

[billfisher]

premium gas only for me. on trips, around town. all the time. you never know when a pesky 2010SS need killing.


if gas prices EVER get to me where i think about it, ill retune it stock and put 2.73's in it.

 

[jaybertx]

People are driving around in $30k+ cars and are concerned about spending an extra $3 or $4 per trip to the gas pump?

 

[dhcolesj]

Well, yea. Puttin' all that money in the car, now we're scrimping where we can to pay for it.

No, just wanted to know how it handled it. Like I said the 87 is as low as I'll go, but I just wanted to see. You know what they say about curiosity.

 

[2011MustangGT]

Thanks for all the input

 

[WMDPALMER]

Where I am at it will cost me more for 87 than 93 octane. We have to go on the economy to get 87 and pay in Euros which is like paying $5 a gallon vs. $3.80 for 93 octane.