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Gas Mileage Realities And Tips... post your tips on HOW TO get good gas mileage

9926 Views 43 Replies 22 Participants Last post by  DAC17
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Post your tips on HOW TO get good gas mileage - my experiences and tips are below:
This thread isn't about "gee, I got horrible gas mileage" - this thread is to assist those who are getting bad gas mileage with tips from those of us who are getting good gas mileage, so, hopefully, you can do the same.


I just did 281.6 miles, and got 27.4 mpg (27.3 mpg by the time I let the car idle while taking the photo below). And that's on my heavy BF Goodrich All Terrain T/A KO2 LT tires.

MY TRIP COMPUTER IS GENERALLY
OFF NO MORE THAN ½ MPG
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Toughest thing is, people don't realize that EPA Highway Fuel Economy testing is 60 mph and less (this is the EPA's tests, not Subaru's). Even so, careful use of the accelerator (as little use of it as possible other than to hold speed) can result in great MPG.
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Even though 2/3 of my trip was 70 mph (everything to NYC), and the rest was between 50-60 mph (NYC to my home exit) followed by 3 miles at 47mph, I still managed to beat EPA ratings. I was fully in "automatic" mode the entire way (no manual shifting, even though the mountains), with ACC in Adaptive mode. I did remove my roof rack for this trip (they eat gas mileage).

Things against me:
  • Very heavy BF Goodrich All Terrain T/A KO2 Light Truck tires (five of them, counting the hitch mounted spare).
  • COBB AccessPort running 93 octane tune
  • Hundreds of pounds of gear
  • Drove through the Adirondack High Peaks Region, and made some stops (such as the photo stop for the photo I posted earlier).
  • Drove through the Catskill Mountains.
  • ⅔ of my trip was at 70 mph

So, remember, it's not that the fuel ratings of the car are wrong. They are not. If you live in Utah, you will probably never make EPA ratings, because the speed limit is 20 mph OVER the EPA's Highway test ratings' maximum speed.
Speedometer Odometer Trip computer Motor vehicle Light

If you live somewhere where you can keep the speeds at 70 mph or below, and not keep changing speeds (as traffic sometimes requires), most of you CAN make EPA ratings, especially because most of you are not running tires as heavy as mine. A friend made a nice little graph of what speeds gas mileage really starts to suffer.
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ALSO REMEMBER...
When I am enjoying using my turbo, my highway gas mileage is only 21-23 mpg. Adjusting my driving habits netted me Almost 4.5-6.5 mpg better.

KEY THINGS:
  • ACC isn't magic. Key factors involved is what the traffic in front of you is doing. If your cruise is set at 70 mph, and your Ascent has to keep slowing to 50 and then speeding back up, you will be eating gas. To get great gas mileages, I try to drive at as steady of a speed as possible.
  • The Ascent has a turbo, with a quick tip-in point. Unless you learn your throttle, you're going to be burning gas.
  • It's fun to floor the Ascent, but, don't do it and expect good gas mileage.
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  • MOST OF YOU live in areas where the speed limit is 65, 70, 75 or higher. If you're driving over 70 mph, you will rarely, if ever, see EPA highway ratings, because the speed for the testing is 60 mph or less.
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  • NO, Subaru can't just make up their own tests. Car manufacturers follow the EPA testing, as they are required to.
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  • The Ascent has a massive and flat front end, as required to suck in all the air the turbo needs and to keep engine and CVT cool - so, yeah, making gas mileage ratings may have been easier on your previous, smaller, turbo vehicle. The Ascent is a big 7/8 passenger car.

Maybe EPA Highway Testing speeds need to be updated.

Instead, they added a "High Speed" test, but that's not the data on the EPA Required "City/Combined/Highway" posts/stickers.
So, until things change, I guess it's a matter of being realistic with our expectations. Next time I go cross country, I know I can't make EPA ratings, because I will be traveling considerably faster than the 60 mph speeds that the EPA requires for testing highway gas mileage.
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on days i fill like "i need to get good gas mileage" , i take Foreter out ..:cool:

but for Ascent , keeping it under 2500 rpm ..
I resemble that remark. Literally. Our Forester is the "ratting around" vehicle, although honestly, even it suffers from short trip syndrome.
I concur with most other high mpg members, I usually set the cruise on the highway at the set speed limit, easy throttle close to home, correct tire pressure, keep air filters clean and avoid remote start or letting the car idle long periods of time. I avoid long line drive thru by parking and going in. I don't do this necessarily to get good mileage just driving habits I have. My gas milage numbers were always good with my previous vehicle which was a Jeep.
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I'm waiting for "break-in period" to end (currently 3100 miles). I've owned many vehicles, and am almost always able to beat the EPA figures through pretty conservative driving. Not hypermiling, but trying to be somewhat reasonable with the throttle/coast-down applications, etc.) But I struggle to get 18 around town and 24 highway (at 65-70). I know winter blend gas hurts by about 2 mpg. Tire pressure 2 pounds above placard, and top tier 87 gas always. No additional weight stored in the car. Anecdotally, these cars seem to have a broad range of mpg's despite driving styles. Hoping for a breakthrough by spring.
I'm waiting for "break-in period" to end (currently 3100 miles). I've owned many vehicles, and am almost always able to beat the EPA figures through pretty conservative driving. Not hypermiling, but trying to be somewhat reasonable with the throttle/coast-down applications, etc.) But I struggle to get 18 around town and 24 highway (at 65-70). I know winter blend gas hurts by about 2 mpg. Tire pressure 2 pounds above placard, and top tier 87 gas always. No additional weight stored in the car. Anecdotally, these cars seem to have a broad range of mpg's despite driving styles. Hoping for a breakthrough by spring.
When we owned a 2019 Touring, we had lots of issues with the car - especially the clunky transmission, and one recall after another. But, getting good highway MPGs was not one of them. With only about 1K miles on it, we took a trip to Cooperstown (200 miles each way with hilly terrain) and got MPGs in the low-to-mid 30s to and from. I never used cruise control, but I did use the paddle shifters to keep it in high gear whenever possible. It did take work, though, as the tranny was almost constantly searching for the "right" gear.

Around town, it was another story. Keeping the RPMs below 2K was often impossible. Our city MPG was always in the mid-to-high teens.
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Just thinking.......
If you drive 100 Miles 80 m/h. You will get there faster with bad gas mileage.
Then you drive 100 Miles at 60 m/h you get great mileage.
But your car will run longer ......burning gas longer.......
So isn't that the crazy thing........😊😊
Just be glad you're not trying to get your Ascent to orbit. Thanks to the rocket equation, 85% of an orbital rocket by weight has to be fuel. You've got the amount of fuel you need to lift the payload, but then extra fuel to lift the base level fuel, and more fuel to lift that, etc, etc. Here's a chart from NASA on fuel-to-structure percentages. MPG straight up is way worse that MPG straight forward!

VehiclePercent Propellant (fuel)
Large Ship3
Pickup Truck3
Car4
Locomotive7
Fighter Jet30
Cargo Jet40
Rocket85
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While shopping for a new Ascent, I found cross-bars are very popular add-ons. Therefore many of your cars may have those as well even though you are not carrying anything. Here is an article from Consumer Reports showing that even just an empty roof rack can negatively impact your gas mileage. Although smaller than a roof rack, to be on the safe side, take down the crossbars when not using them.

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Fayetteville, PA to Albany, NY, about 400 miles, average 31.5 mpg. Cruise on, drove 55-60, via 77 to 87 north. Returned via 88 SW to 81 S, avg 27.8 mpg, cruise on, 60-65 mpg. I have 31k on the odometer at start of trip. Synthetic oil change before start of trip.
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So on my 2021 Limited with about 45,000 miles on it. Last oil change was at around 41K. A few days ago, when I shut off the car I was getting 24.5 mpg. The next day, I start it up and I'm getting 22.5 from the get go. I go over Snoqualmie Pass and start the long descent into the Seattle area; usually on this trip the fuel economy jumps up to about 27 or 28 mpg. This trip, it remains at about 21.5. It's been this way for days now. I'm wondering if my air filter just clogged up or if I should check something else? FYI, most of my driving is highway and I drive at the speed that gives me the best fuel economy; generally in the 65 to 75 range.
Any insight will be most appreciated.
So on my 2021 Limited with about 45,000 miles on it. Last oil change was at around 41K. A few days ago, when I shut off the car I was getting 24.5 mpg. The next day, I start it up and I'm getting 22.5 from the get go. I go over Snoqualmie Pass and start the long descent into the Seattle area; usually on this trip the fuel economy jumps up to about 27 or 28 mpg. This trip, it remains at about 21.5. It's been this way for days now. I'm wondering if my air filter just clogged up or if I should check something else? FYI, most of my driving is highway and I drive at the speed that gives me the best fuel economy; generally in the 65 to 75 range.
Any insight will be most appreciated.
According to Consumer Reports: “We measured gas mileage while driving at a steady 55, 65, and 75 mph in a Nissan Altima and Toyota RAV4. Reducing speed from 65 mph to 55 mph improved fuel economy by 6 mpg in the Altima and 8 mpg in the RAV4.

The penalty of cruising at 75 mph, rather than 65 mph, was almost 7 mpg in the Altima and 6 mpg in the RAV4.”

There is a reason that in some cars, 55 MPH is specifically marked in the speedometer to remind people this is the speed at which max fuel economy can be achieved. I dont think this has changed despite the technologies in the drive trains. Also the ethanol contents in the gas can reduce efficiency.
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Just sharing a data point...

Our Ascent Limited 2023 is only a month old, around 600 miles.
  1. The first tank, which the dealer had filled and probably had some winter-blend oil, gave us horrible mileage, in the 15s in town (we asked ourselves why we sold the Land Rover LR3, which got ~14 in town).
  2. Next tank, which I used 91 octane gasoline, it improved to ~18s in town.
  3. The following tank, which again was 91 octane gasoline, it improved to ~19.5 in town and ~27.5 country/highway driving (see photo below).
So, it definitely improves, and I am hoping that it will improve more. And drastic difference between in town and country/highway driving.

I drive conservatively (always with kids anyway) — slow acceleration, minimal idling, and almost always below 2K RPM.

Speedometer Tachometer Gauge Vehicle Trip computer
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Just sharing a data point...

Our Ascent Limited 2023 is only a month old, around 600 miles.
  1. The first tank, which the dealer had filled and probably had some winter-blend oil, gave us horrible mileage, in the 15s in town (we asked ourselves why we sold the Land Rover LR3, which got ~14 in town).
  2. Next tank, which I used 91 octane gasoline, it improved to ~18s in town.
  3. The following tank, which again was 91 octane gasoline, it improved to ~19.5 in town and ~27.5 country/highway driving (see photo below).
So, it definitely improves, and I am hoping that it will improve more. And drastic difference between in town and country/highway driving.

I drive conservatively (always with kids anyway) — slow acceleration, minimal idling, and almost always below 2K RPM.

View attachment 21140
So you say you drive conservatively (with kids), yet you show us a clear photo of the car while driving at over 50 mph? I’ll assume someone else took this picture? Am I missing something new about how to drive safely?
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Short trips lots of idling while waiting for kids it's usually around 22with fully packed on highway
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Take a look at Fuelly.com if you want to see a large number of reported MPG’s. I can’t get much more than 23, even in extended highway driving.
Take a look at Fuelly.com if you want to see a large number of reported MPG’s. I can’t get much more than 23, even in extended highway driving.
My overall experience with highway driving over the past four years has been 26.5+ typical with some tanks as high as 28, depending on conditions. I don't exceed 70 mph unless I have to to pass someone...65-70 is where I stay which is pretty much the limit here in the east.
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So you say you drive conservatively (with kids), yet you show us a clear photo of the car while driving at over 50 mph? I’ll assume someone else took this picture? Am I missing something new about how to drive safely?
My husband took it from across the passenger seat.
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So you say you drive conservatively (with kids), yet you show us a clear photo of the car while driving at over 50 mph? I’ll assume someone else took this picture? Am I missing something new about how to drive safely?
Not sure how driving conservatively has to do with anything about a photo being taking at 50mph? Being lite on the gas pedal can be done regardless if you drive 5mph or 50mph, breaking the laws or not.
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Not sure how driving conservatively has to do with anything about a photo being taking at 50mph? Being lite on the gas pedal can be done regardless if you drive 5mph or 50mph, breaking the laws or not.
If the driver is taking the picture, he or she is not paying full attention to driving. Sorry, I’m one of those “old school” guys. Our culture has changed a lot.
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If the driver is taking the picture, he or she is not paying full attention to driving. Sorry, I’m one of those “old school” guys. Our culture has changed a lot.
I'm not disagreeing (also not saying the driver is doing this or not).

The point is, the drivers conservative driving of the gas pedal is not coupled to their safeness level. Taking a picture of the speedo, driving without a seat belt, running stop signs, etc, all have no bearing on the Ascent's MPG.
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I'm not disagreeing (also not saying the driver is doing this or not).

The point is, the drivers conservative driving of the gas pedal is not coupled to their safeness level. Taking a picture of the speedo, driving without a seat belt, running stop signs, etc, all have no bearing on the Ascent's MPG.
You’re right. It just seems like inconsistent behaviors, that I guess could both be classified as “conservative”.
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