MPG at 75-80 MPH?

[5.0yote]

Can you do a test of about 20miles on the highway on cruise? I believe that way we’d have a good baseline to give you our results. I think you should be at least 28mpg without a tune assuming you putting 93octane. I’m not familiar with cold weather/engine effect. When was the last time you check/changed plugs?

There are also other issues in the winter that makes your car worse on gas one being air is denser due to the cold which makes it cause more drag and friction when you drive, your optimal oil temp and other fluid temps need more time to get to optimal temps so more friction. Your tire pressure is lower, and gas historically is less efficient and has less power in the winter than summer due to different grades.

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[TorqueMan]

I tend to get better gas mileage above 70MPH in 5th gear (28.4mpg average)

There must be something else going on here besides gearing. All things being equal, you will burn less fuel to make the same power at a lower RPM. Why? Because there is less parasitic friction on internal engine parts at lower RPM.

The only time I can image better economy in a lower gear would be with the engine under significant load, such as driving into a big head wind or uphill. In those cases getting the engine closer to peak torque can improve efficiency.

 

[Ebm]

I believe some of the difference in mpg is tire size. I'm running 255/40/19s. Some of you guys are running 18s. Although how someone gets 33-34 mpg in this car is beyond me.

 

[TorqueMan]

Although how someone gets 33-34 mpg in this car is beyond me.

With a tailwind going downhill...

 

[5.0yote]

There must be something else going on here besides gearing. All things being equal, you will burn less fuel to make the same power at a lower RPM. Why? Because there is less parasitic friction on internal engine parts at lower RPM.

The only time I can image better economy in a lower gear would be with the engine under significant load, such as driving into a big head wind or uphill. In those cases getting the engine closer to peak torque can improve efficiency.

In my case I know what it is exactly and its hills, my commute has a lot of up and down driving and 6th gear does not have the gearing for it, when I am on cruise control in 6th its a dog on a good part of my commute 95 south. However in 5th gear it gets the job done with better fuel economy.

 

[ElAviator72]

I believe some of the difference in mpg is tire size. I'm running 255/40/19s. Some of you guys are running 18s. Although how someone gets 33-34 mpg in this car is beyond me.

I've gotten over 30 ONCE (I filled up at a VP Racing fuels with ethanol-free premium ).

 

[Spykexx]

Can you do a test of about 20miles on the highway on cruise? I believe that way we’d have a good baseline to give you our results. I think you should be at least 28mpg without a tune assuming you putting 93octane. I’m not familiar with cold weather/engine effect. When was the last time you check/changed plugs?

Haha 28 mpg. I do 30 miles to work, and on screen shows me at about 19-20 @ 72MPH.

My cluster reports 26-27MPG on my normal commute to work (4.5 miles, 1-2 stop signs, two lights, and four. Turns). Since switching to winter tires and winter gas, I’m down to about 24.5MPG. I typically start coasting well in advance of stopping and don’t accelerate too hard.

On the highway cruising at 65 I can get 37-38MPG. If I cruise at my preferred 78 on the interstate, it goes down to 32-33.

2017 Ecoboost Premium MT, 3.31 gears, 235 tires.

LOL, I don't even get that good of gas mileage when my car is off and parked.

 

[Ebm]

.

Haha 28 mpg. I do 30 miles to work, and on screen shows me at about 19-20 @ 72MPH.



LOL, I don't even get that good of gas mileage when my car is off and parked.

On premium(93) set the cruise at 65 mph on the highway, get off the highway and go 50 mph the rest of the way to work. This 50 mph city driving is minimal stop and go. This whole trip takes 22 minutes. 14 highway miles and 8 city miles. Readout after is 21-22 mpg.

 

[TorqueMan]

Haha 28 mpg. I do 30 miles to work, and on screen shows me at about 19-20 @ 72MPH.

Wow. I've never seen 38 mpg on the highway, but I haven't seen 19 mpg either. There aren't too many hills around the quad cities where you live, but I do believe they reformulate the gas there in the winter like they do here around Saint Louis. Between that and the cold temps, I've seen a reduction in mileage, but I'm still averaging 27 mpg over a tankful for mostly highway driving between 65-70 mph, with an occasional excursion to 80+ when I need to get around a slowpoke.

Here are things that affect fuel mileage in order (I believe) of highest impact:

• Aggressive driving (using more than half throttle to accelerate)
• Cold weather, especially if you make frequent short trips
• Higher highway speeds
• Excessive idling (which is why you shouldn't idle to warm up, just drive it carefully until it's warm)
• Hills
• Extra weight
• Tire pressure

I didn't include tuning in the list. In older cars a poor tune (improper timing/mixture, etc.) could severely impact economy, but aside from maintaining your spark plugs and using good quality gas, we don't have control over that in modern cars. That said, if the computer tune you are running on your car isn't stock then you can't expect to see EPA estimated economy numbers.

Consider trying this: Put the Fuel Economy display on your center screen while you're driving and watch it. There are a couple of different Trip/Fuel screens, but the Fuel Economy screen will show instant and average (average is since you last reset). With this screen up you see exactly how your driving style is affecting economy. And if fuel economy is important to you, you also can use this screen to train yourself to maximize economy by changing your driving style.

Do not trust the average fuel mileage indicated by the computer--check it manually. Fill the tank, then reset your trip gauge and let it run over three tanks of gas during normal usage (don't include any long trips or weeks off work if you want an accurate "normal usage" average). Keep track of how much fuel you put in the tank for each fill up, then compute your mileage by dividing the miles by gallons used. Three tanks should be enough to average out variances. Once you have a baseline you can compare it to the average indicated by the computer to get an idea of how accurate it is. Mine has been off by up to 3 mpg. Armed with an accurate average fuel economy number, you can try different things to see if there's a way to improve it.

One of the best ways I've found for improving mileage on the highway (other than keeping it under 75 mph) is to pay close attention. Put the cruise control on and keep it on as much as possible. It costs you fuel every time you have to accelerate, so don't slow down unless you have to. And if you have to slow down, don't use the brakes unless absolutely necessary. Any time you have to step on the brakes you are essentially using the fuel you just burned while accelerating to heat up your brake discs. You can avoid using the brakes by simply watching ahead and planning carefully.

Let's say you're cruising in the right lane. There is a car in the right lane in front of you going slower, and another behind you in the left lane going faster. I've seen some people in that situation keep closing on the car in front until the last minute, then hit the brakes because the car that was behind is now beside them and there's no room to pass the slower car. If instead he had simply planned ahead, he could blip down one or two miles per hour (or more--whatever it takes) on the cruise control to give the car behind more time to complete the pass, then blip back up to go around the slower driver. No gas wasted by stepping on the brakes. You can make a game of it to kill time on the commute.

Another thing is following distance. People who drive in the left lane during rush hour tend to tailgate--I assume it's to prevent people in the right lane from getting into the left lane based on the way they behave whenever it happens. The problem is people in the right lane are coming over when they need to pass whether you make room for them or not, and when it happens the person tailgating trying to prevent it slams on the brakes, which makes the person behind them slam on the brakes and so on. Then they're immediately back on the throttle--sometimes heavily--to speed back up and prevent a gap that someone else might merge into. So they end up on the gas or on the brakes all the time, which is a recipe for poor fuel economy.

Instead, why not leave a gap in front of you that people can merge into? This provides a couple of benefits. First, there's no surprise (or anger) when someone actually merges into the fast lane in front of you to complete a pass--you've planned for it. No need to stomp the brake (usually) and throw away your precious momentum. Second, when someone inevitably cuts in front of someone in front of you and they stomp their brakes—you were paying attention and saw it coming, right?—you have a big enough gap so that you can simply slow down by coasting without having to use the brakes. Yes, you're still giving up some momentum, but the entire time you are coasting with your foot off the gas you're not burning any fuel.

For me, I've found the best way to maximize economy is to just stay out of the left lane unless I need to pass. If you drive in the left lane around here the person behind you will tailgate no matter how fast you are driving (80 in a 60 zone? GET OUT OF MY WAY!) and the anger/competition brings out the absolute worst in other drivers. Life's too short to put up with that kind of $h!t. I stay out of the fast land, set the cruise on 67-68 and click up or down to keep with the flow. I'll occasionally accelerate up using the gas pedal to get in the left lane to pass, then get back in the right lane and coast back down to my previous speed. No stress, and good for fuel economy to boot.

It seems kind of counterintuitive that you would drive a performance car in a way that avoids using its acceleration performance, but fuel mileage is a kind of measurable performance too. You're commuting, not racing, so try to maximize performance for that regime. Save the acceleration fun for those times when you can really enjoy it. Unless you don't mind using the gas, that is.

If you make an honest attempt to maximize your economy and you're still getting 19 mpg on the highway, then I would say there is some underlying issue with your car that needs repair.

 

[Blue Moon]

TorqueMan, have you been spying on me? That's how I drive... most of the time. Every now and then I just have to step on it and have fun. According to my screen, I've averaged 28.4 mpg over the last 7000 miles. And my best 0-60 is 5.5 secs.

 

[TorqueMan]

TorqueMan, have you been spying on me?

My minions are everywhere...

 

[Seesnax]

Started a new job at the end of October, and my commute is 88 miles, each way, five days a week (yes I am planning to relocate closer to work within the next 6-9 months). Luckily, my trip is mostly flat (a few hills and valleys), and 95% rural and national highways (55, 65, and 70 mph). Basically, about two miles from my house, I get up to 55+ mph, and stay there for the next 90 minutes (I do slow down a bit to pull into the parking lot at work...).

I have a 2016 automatic EB that I bought used with about 38k on the odometer (well over 42k now!). The first couple of weeks I drove the car to work, I was still learning it, and it was dark out both in the morning and the evening, so I pretty much drove it like a nun. I averaged 31-33 mpg almost every day on regular unleaded. I do see a drop in the mileage when travelling 70+ mph versus 55-60, probably between 0.5 and 1 mpg. As mentioned above, I do get the occasional burst of acceleration to pass slower traffic.

Over the past couple of weeks, with stupidly cold temperatures (we finally made it above freezing for the first time in two weeks), I am now averaging around 30mpg for the same commute. Granted, this does include longer warm-up times both in the morning and the evening, but I can't imagine that being the sole cause of the drop in mileage. I too suspect the colder denser air, and/or reformulated gas.

Just my $0.02, and a note that 30+ mpg is very possible for these cars, at least for an old guy....

 

[GJarrett]

Mine is highly sensitive to any aggressive input on the go pedal, to stop and go city driving, and to high interstate speeds. I recalibrated my mpg reading to be accurate per a thread on here long ago, so my readout is accurate. I can set my cruise control at 60mph on flat highways and get 36+ mpg every time roundtrip (to offset any head/tail wind etc issues). At 70 mph I get down to 30-31 or less sometimes. I've never driven it 80 mph+ for extended times but expect it gets mid 20's mpg at that speed, certainly less than 30. I get low 20's many times burning a tank that is mostly city traffic. Combine that with 80mph runs and 22 mpg does not sound too out of line to me.

A couple of weeks ago I had the chance to cruise some very flat beach highways connecting gulf coast towns with no traffic, using cruise control at 49-50mph for extended periods of time. Result - 39 mpg. That's not a misprint. On the other hand, in city traffic and/or spirited driving I can see mpg in the teens easily. Hit the boost on this car and it sucks gas like any other 300+ hp engine. Ponies use fuel; if you use more ponies you use the fuel to feed them. I've ran it at an HPDE event four days; on a road course it gets 7.7 mpg.

I've never reset my trip #1 odometer so it is lifetime for the car. At 29k miles my overall mpg is 24.9 mixed city/hwy and I almost always drive it like a grandmother 99% of the time. If you're doing lots of city stop-and-go combined with 80mph on the highway, 22 mpg may be appropriate to expect.

 

[K-Roll302]

I do have a PP car. My personal rule of thumb is not to put the vehicle into 6th gear below 55 MPH. You definitely don't want to do something like accelerate uphill with the car in 6th going 55... (LSPI). 6th is pretty usable in a PP car. I use it all the time for freeway cruising, and for state highways and such (as long as traffic is moving at 55+ MPH).

The EBM is geared kind of funny, too...in a typical 6 speed manual, gears 1-4 are as expected, with 4th being direct drive (1.00:1), 5 being a mild overdrive (usually something like 0.92:1), and 6 being a super duper overdrive. However, our gear ratios have 5th being direct drive, and 6th is our only overdrive gear. Also, 3.55 in most other cars would be considered a fairly normal axle pinion ratio, but I guess Ford went for the kill with favorable gearing for fuel economy. Isn't 3.10 also used in some ecoboosts? (automatic, non performance pack?).

Actually, 5th is the 1.00:1 ratio gear.

 

[ElAviator72]

Actually, 5th is the 1.00:1 ratio gear.

If you read that post a little closer, that's exactly what I said...I said a normal car with a 6 speed has 4th at 1:00-1 The Mustang is the wierdo...

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