Fuel requirements

[JimmyTwoTimes]

So I've ordered a GT and I'm excited about owning it, but I'm also a little leery about the fuel economy. Two questions:

Based on existing experience with Coyote engined Mustangs, what do people think the real-world MPG will be? Also, do you think premium fuel will be required, or will it still take 87 octane the way it currently does?

I'm asking because I used to own a Mercedes that required premium and got 5-7 mpg (not a typo) and it really put me off gas guzzlers just on principle. I get 20-21 mpg with my current V6 Mustang -- and up to 34 mpg if I'm doing pure, straight-shot highway miles for a full tank -- and I obviously don't expect to get that with the GT, but I'd be happy if I could see at least 16-17 mpg with the GT in mixed driving. Any odds of that happening?

Also, with respect to the octane requirements... where I am, premium fuel costs about an extra dollar a gallon over regular fuel, or about $5 / gallon total. So if it's requiring premium fuel, a car that gets 16 mpg is the equivalent of a car that gets 13 mpg but runs on regular.

It's of course not my primary concern, or I would have bought a Smart4Two. But I'm curious to hear people's thoughts.

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[chopsui]

16-17 mixed is no problem in a GT

 

[Wild Stang]

Fuelly.com is a pretty good resource to get real-world gas mileage information. Here are the links for the 2013 & 2014 Mustangs:
http://www.fuelly.com/car/ford/mustang/2013
http://www.fuelly.com/car/ford/mustang/2014

If you click on a car and go to the profile, it will list the engine type & sometimes it lists what percent of city vs highway they usually drive. I'm pretty sure you'll see at least 16-17 mixed based on what I see for 2014s on Fuelly.

I drive almost 100% city, so I get pretty crappy mileage in my '94, but better than your Mercedes :shocked:

 

[Free Agent]

I'm asking because I used to own a Mercedes that required premium and got 5-7 mpg (not a typo)

What was it a tractor? Or did you always keep your foot to the floor and let it idle 24 hours a day. ;)

Also, with respect to the octane requirements... where I am, premium fuel costs about an extra dollar a gallon over regular fuel, or about $5 / gallon total. So if it's requiring premium fuel, a car that gets 16 mpg is the equivalent of a car that gets 13 mpg but runs on regular.

I thank my lucky stars I don't live where you do. We have a 20 or at most 30 cent difference between regular and premium. I can get 93 octane for less than $4 a gallon. I may live in the sticks but sometimes it pays off.

Let me ask this, how many miles do you drive a year? 10000 miles at 20 miles a gallon is 500 gallons of gas a year. Multiply that 500 by that extra $1 a gallon you pay and its $500 more per year. Just try to figure out how many gallons of gas you use a year and multiply it by $1 and you can see the difference between regular and premium.

 

[deeps29]

What was it a tractor? Or did you always keep your foot to the floor and let it idle 24 hours a day. ;)

LOL!! :lol::lol::lol:

 

[JimmyTwoTimes]

What was it a tractor? Or did you always keep your foot to the floor and let it idle 24 hours a day. ;)

It was a 1991 Mercedes 560SEL with a cracked header. Every time you'd hit the gas, it would billow black smoke out of the back like a deisel. Cost me a grand a month in repairs for the two years I owned it. Perfect interior, but I gave it away for free just to get rid of it.

Let me ask this, how many miles do you drive a year? 10000 miles at 20 miles a gallon is 500 gallons of gas a year. Multiply that 500 by that extra $1 a gallon you pay and its $500 more per year. Just try to figure out how many gallons of gas you use a year and multiply it by $1 and you can see the difference between regular and premium.

I average just about exactly 12,000 miles a year - probably 80% highway, but a lot of highway driving in NYC isn't really "highway" driving, if you know what I mean -- a lot of two hours to go five miles type situations.

Like I said, the money doesn't really matter to me as much as the principle - that Mercedes will have me, for the rest of my life, hating the idea of cars that take only premium and can never crack 100 miles on a tank. My V6 Mustang gets at least 250 miles a tank and it's glorious.

 

[Grimace427]

It was a 1991 Mercedes 560SEL with a cracked header.

...Like I said, the money doesn't really matter to me as much as the principle - that Mercedes will have me, for the rest of my life, hating the idea of cars that take only premium and can never crack 100 miles on a tank.

You shouldn't worry then as none of the new Mustang models(with maybe the SVT as an exception) will require premium fuel.

BTW I'm a benz tech and we have a guy straight from the factories in Germany who works on nothing but those older cars. Been doing it longer than I've been alive and whenever he brings them into the shop everyone goes running for fresh air because he stinks up the entire shop! The diesels are unbearable!

 

[Free Agent]

It was a 1991 Mercedes 560SEL with a cracked header. Every time you'd hit the gas, it would billow black smoke out of the back like a deisel. Cost me a grand a month in repairs for the two years I owned it. Perfect interior, but I gave it away for free just to get rid of it.



I average just about exactly 12,000 miles a year - probably 80% highway, but a lot of highway driving in NYC isn't really "highway" driving, if you know what I mean -- a lot of two hours to go five miles type situations.

Like I said, the money doesn't really matter to me as much as the principle - that Mercedes will have me, for the rest of my life, hating the idea of cars that take only premium and can never crack 100 miles on a tank. My V6 Mustang gets at least 250 miles a tank and it's glorious.

Looks like the GT can run on 87 although 91 is recommended for optimum performance. Run on 87 and the computer will probably cut timing and reduce your HP by a small amount. At 12K miles a year and 12 mpg you may go through 1000 gallons a year, that would be $1000 for premium in your area. If money isn't an object don't sweat it. Of course if you are doing 80% city driving you will never need the full potential of the engine on 91 octane anyway. Just personally I never run anything lower than 91 in either of my V8 vehicles that recommend premium for optimum performance. Is it a waste? Maybe. But when I plant my foot I want ALL the HP/TQ not the computer pulling timing because it wants to detonate on lower octane fuel.

 

[SunkenShadow]

To be honest, I'm in a 96 E320 right now and kind of hate it. Nice place to be but not fun to drive and gas mileage isn't great. I don't the mileage on a GT to be better but I expect it to be a heck lot more fun.

One thing I've learned is that if you want to have fun or get what you want, you have to pay to play. If you are worrying so much about it, you are probably doing something wrong.

 

[jeebuspwnz]

Just because it WILL run on 87, doesn't mean you should do it. Premium is recommended. This means the car will run an optimal amount of ignition advance with Premium and the motor will experience minimal knock, and pull timing less frequently because of it. You will make more power and get better mileage.

All cars can technically run on 87 now, because the ECUs have a ton of flexibility in their tune. Personally though, it's a performance car...let it perform.

 

[EXP Jawa]

Just because it WILL run on 87, doesn't mean you should do it. Premium is recommended.

Recommended, as you say, for peak performance. But saying that you shouldn't run 87 just because you can is a bit inaccurate. The phrasing implies that doing so would be risky, and frankly, it isn't. There isn't anything that they're saying is ok that isn't perfectly acceptable. Frankly, I doubt many people will loose much sleep if their car makes 10 HP less when they're saving $5 per fill up under normal driving, nor will they notice the difference. There's nothing wrong with filling with premium when going to the track, auto-X or whatever, but running 87 daily.

 

[Grimace427]

Recommended, as you say, for peak performance. But saying that you shouldn't run 87 just because you can is a bit inaccurate. The phrasing implies that doing so would be risky, and frankly, it isn't. There isn't anything that they're saying is ok that isn't perfectly acceptable. Frankly, I doubt many people will loose much sleep if their car makes 10 HP less when they're saving $5 per fill up under normal driving, nor will they notice the difference. There's nothing wrong with filling with premium when going to the track, auto-X or whatever, but running 87 daily.

I agree. Commuting around town at 35mph isn't putting the engine under enough load to make any difference regarding octane. If you go racing however it would definitely help to have premium fuel in the tank.

 

[lostwon]

About 87 vs 91 octane in ordinary driving.

I've been operating a 2012 GT for almost three years now in SoCal, where prices are high. Found out from a reliable source that the peak horsepower difference running 87 and 91 with 10% ethanol is about 7 HP. Out here there's a 20 to 30 cent difference in price. So I tried running 87 and never had a problem. I run autocross successfully, and have never missed the 2/3% lost power. The Coyote is a very efficient engine, and I see high teens average miles per gallon in combined driving. From a low of 12 or so racing to mid twenties fast steady highway cruising. I have the manual with 3.31 gears.

Obviously, a lot of fuel economy is how you drive, so your mileage may vary. I see no reason that the S550 won't do as well, unless they bump the ethanol up to 15% in the gas; like I heard might happen in the next few years. Ethanol, of course doesn't have the energy that gasoline does, so more ethanol means less mpg.

 

[5.0GT]

I have a 2013 and definitely notice a big difference between 93 and 87...93 gives you more pep and smoother throttle of course. 87 feels OK but it feels like I have lost a good amount of torque when I run it, which I hardly ever do. I run 93 all the time with mods that I have because there are plenty of 5th gen camaros out there that get a beating when they pull up at the light.

 

[Sal JC]

I only use 87, mostly city, avg 18-19. A few years ago I had an 06' v6 and got 20-21.
2mpg difference for literally double the HP isn't bad.

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