Post your MPG's

[Old 5 Oh]

Nice. So that's a GT with 3.15's correct (just making sure). That sounds like what I was expecting.

I really have to decide between the 3.15s and 3.55s.

Base manual is 3.31s, right? But about the same total gear since the AT has a little less OD in 6th gear? I haven't done all the math on these cars yet but I think I remember that.

As to Octane, all I can tell you is my 09 GTI "required" premium, but ran fine and got the same mileage whether I ran 87, 89 or 91 on our flat highways.

Sponsored

 

[Spartan]

Base manual is 3.31s, right? But about the same total gear since the AT has a little less OD in 6th gear? I haven't done all the math on these cars yet but I think I remember that.

As to Octane, all I can tell you is my 09 GTI "required" premium, but ran fine and got the same mileage whether I ran 87, 89 or 91 on our flat highways.

Yah I've always read Octane will not affect MPG in the slightest.

And yah I meant the 3.15s for the auto.

 

[Old 5 Oh]

Looks like we are seeing GT highway MPG ranging from 21-22 for the PPs up to over 26 for the 3.55-3.15 crowd. In my book (2,500 miles a month) that's at least worth noting, but by the math it's less that 20% different. So if you are driving 500 miles a month it's not worth worrying about.

Personally, I think 26+ on the road for a 435 HP GT is a freaking miracle.

 

[JoeDogInKC]

PP's are higher than 21-22. I'm getting better mileage with a new, non-broken in motor than I was getting in my 2013 A/T GT Premium with 3.15's. I've seen 24mpg average on the highway and it could easily get more than that. In the 16,000 miles I drove the 2013, I averaged 19.4mpg overall and it was mostly highway miles. I averaged about 22mpg highway on that one. To get 3.73's, more power and better gas mileage to boot is absolutely astounding!

 

[RB510]

PP's are higher than 21-22. I'm getting better mileage with a new, non-broken in motor than I was getting in my 2013 A/T GT Premium with 3.15's. I've seen 24mpg average on the highway and it could easily get more than that. In the 16,000 miles I drove the 2013, I averaged 19.4mpg overall and it was mostly highway miles. I averaged about 22mpg highway on that one. To get 3.73's, more power and better gas mileage to boot is absolutely astounding!

Maybe there is something on California cars dragging it down.

I have been driving Katie as gently as possible to try to "hyper mile" it and see if it's driving habits... I have only seen 22 Mpg in strictly freeway driving. As soon as I'm in the city I am lucky to see 14...

Maybe that is why the average is so bad. The freeway-only part is pretty good but the city just drags it all the way down.

 

[Seabee1973]

Maybe there is something on California cars dragging it down.

I have been driving Katie as gently as possible to try to "hyper mile" it and see if it's driving habits... I have only seen 22 Mpg in strictly freeway driving. As soon as I'm in the city I am lucky to see 14...

Maybe that is why the average is so bad. The freeway-only part is pretty good but the city just drags it all the way down.

Yeah, your fuel there sucks, less additives and sulphur content as well as lower octane ratings

 

[Seabee1973]

For premium that is...California emissions is supposed to help mileage but personally I don't see it

 

[RB510]

Does driving in Sport+ mode reduce fuel efficient beyond just encouraging me to get my foot deeper into the loud pedal?

 

[JoeDogInKC]

Here in Kansas City, there are very few 93 octane places. I've run with both 10% Ethanol 91 octane and now ethanol-free 91 octane, mileage appears to be down just a smidgeon with the ethanol-free gas, but sure feels like there is a touch more power on the old butt dyno.

 

[Spartan]

PP's are higher than 21-22. I'm getting better mileage with a new, non-broken in motor than I was getting in my 2013 A/T GT Premium with 3.15's. I've seen 24mpg average on the highway and it could easily get more than that. In the 16,000 miles I drove the 2013, I averaged 19.4mpg overall and it was mostly highway miles. I averaged about 22mpg highway on that one. To get 3.73's, more power and better gas mileage to boot is absolutely astounding!

Good to hear Joe! I'll be most likely getting the GT and with the 3.55's upgrade. I might leave at 3.15 but I kinda want like the concept of being fast out of the light, on ramp

 

[Sc00ter]

The tests by the EPA all ran 87 octane. Octane as far as I know does not affect MPG but affects HP/Torque. It's why there is an * next to the EB engine with a (requires 93 to get the HP/Torque).

Spartan, are you sure about that 87 octane? According to a Car and Driver story back in 2009 (The Truth About EPA City / Highway MPG Estimates), "The EPA has a specialized company manufacture small batches of consistent fuel, which is 93 octane (cars running 50-state certifications get a slightly different, 91-octane “California” blend)." Which kind of makes sense: higher octane = higher torque = earlier shift points = better economy, which is what is what's being tested.

I'd much rather run regular than spend the extra 10%-15% more if it makes no difference, and all I can find on the current EPA site about the gas they use in testing is that their "approved fuel" contains no ethanol and is of a specific density… no octane reference. Any links to current EPA octane info?

 

[Sc00ter]

Maybe there is something on California cars dragging it down.

I have been driving Katie as gently as possible to try to "hyper mile" it and see if it's driving habits... I have only seen 22 Mpg in strictly freeway driving. As soon as I'm in the city I am lucky to see 14...

Okay RB510, gotta ask - why the name Katie for the car? No obvious clues in the color or model, unless it's the Katie-litic converters underneath.

P,S.— Not judging, just curious — there's a Kia Optima named Optimus outside in my driveway as you're reading this.

 

[Spartan]

Spartan, are you sure about that 87 octane? According to a Car and Driver story back in 2009 (The Truth About EPA City / Highway MPG Estimates), "The EPA has a specialized company manufacture small batches of consistent fuel, which is 93 octane (cars running 50-state certifications get a slightly different, 91-octane “California” blend)." Which kind of makes sense: higher octane = higher torque = earlier shift points = better economy, which is what is what's being tested.

I'd much rather run regular than spend the extra 10%-15% more if it makes no difference, and all I can find on the current EPA site about the gas they use in testing is that their "approved fuel" contains no ethanol and is of a specific density… no octane reference. Any links to current EPA octane info?

Here you go.

Says regular gasoline in the chart so to me, that means 87 octane regular gas. Also in the owners manual, it says 87 octane also.

http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=35664

Also for comparison, you can look at the Audi A3 which I know runs on premium and is required and they have the chart with premium listed as the fuel

http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34771

 

[USPSALIMITED]

Looks like we are seeing GT highway MPG ranging from 21-22 for the PPs up to over 26 for the 3.55-3.15 crowd.

PP's are higher than 21-22. I'm getting better mileage with a new, non-broken in motor than I was getting in my 2013 A/T GT Premium with 3.15's. I've seen 24mpg average on the highway and it could easily get more than that.

Hmmm.
Window stickers say 15 city 25 hwy and 19 average for the PP and non PP GT's.

No conclusions from me here, just hmmm.
If there is a big difference a heads up would have been a good thing (although I think everybody expects the PP's to lose a smidge).

 

[Old 5 Oh]

Hmmm.
Window stickers say 15 city 25 hwy and 19 average for the PP and non PP GT's.

No conclusions from me here, just hmmm.
If there is a big difference a heads up would have been a good thing (although I think everybody expects the PP's to lose a smidge).

EPA tests are run on the standard configuration unless there's another configuration that will take up 25% or more of the volume. PP may come close to that with the GT.

I have had enough Mustangs with enough different rear gears to tell you it does make a difference, and not just one or two mpg. There are a lot of things to control for on this site, from driving style to temperature to gasoline type to what everyone defines as "highway driving." But all things being equal I would be completely amazed if a PP and a GT AT with 3.15 gears had less than a 15% spread on "highway" mileage. Really wouldn't be surprised at 20% since that's about what 3.55s would do to a 2.73-equipped Fox.

All that means is there's no free lunch. Everything (like acceleration and responsiveness) has a price, and in this case it's some fuel economy. Everyone gets to take his choice.

Sponsored