09-27-2015, 09:58 AM | #1 |
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optimum speed for x35d mpg
Relatively new owner of 35d here. Had several trips and noticed that best mpg (27mpg ) comes when I cruise at 80 +/-5 mph on 5 hours trip.
If I go 65 the average mpg is actually lower - can you share your observation with your 35d ? I drove with normal 'comfort' setting, no traffic on highway. Thanks |
09-27-2015, 12:08 PM | #3 |
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The lowest rpm in 8th gear without getting the finger from cars passing you. About 55-60 mph and I get 35-36 mpg. My footnote has real life examples (non-mobile version of this site)
Acceleration consumes the most fuel. If you can tolerate a 0-60 in 12-15 slow seconds you will see great results. |
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09-27-2015, 03:11 PM | #4 |
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Where I live we actually have quite a bit of highway with active speed monitoring for quite some miles (traject monitoring). As the Netherlands are mostly flat, the only real influence will be the windcomponent. This effect is not to be forgotten as we are driving a mobile flat or sea container. Slipstreaming behind other cars also has a positive effect.
In zero wind conditions driving just over 60 mph will give me the 6.2L/100KM with a nice tailwind you could achieve these numbers at higher speed, but as soon as the headwind starts blowing it will be 9L and upwards. On average I manage 8.1 (this includes high speed and city), if it's only highway with speed monitoring it's average 7.2L/100KM I drive a 30d with MPPK on 20" summer tires (DUNLOP) |
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09-27-2015, 07:25 PM | #6 |
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I have to try ECO mode sometimes ,,,more than 10 minutes I did ....
The car is so noticeably slow that I switched to comfort. I'm perfectly happy with 27-29mpg highway cruiser at 80mph but wanted to hear other people experience. I would say I drive pretty aggressively and probably will never get more than 30 mpg but, again, it's a fine with me. |
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09-27-2015, 10:23 PM | #7 |
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I use Eco Pro maybe 1% of the time. The only real benefit I see of it is maybe the coasting mode on highways. I'd never use it around town, it's just so weak, and that god awful start /stop which I can't stand. I always turn it off.
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09-27-2015, 10:38 PM | #8 |
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My best is between 65 and 70mph. I never use ECO-whatever and I get about 32-ish, figured long hand at fill-up. My computer shows 34-ish and is always about 2 mpg above reality.
Edit: I use sport mode in city traffic, not highway.
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Last edited by 42pilot; 09-28-2015 at 11:26 AM.. |
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09-28-2015, 10:16 AM | #9 |
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Drives: 2016 X5 35d | 2019 X3 30i
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I too am getting 27 mpg combined.
...and have never used Sport or Eco Pro...is always in Comfort mode I suppose... FYI. |
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09-28-2015, 03:48 PM | #10 |
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Here are some interesting facts on MPG Vs. speed. Above about 60 mph your fuel mileage will drop quickly.
Green Car Congress did a study comparing different car model against this topic. Why? 1) Increasing air resistance. "Pushing air around actually takes up about 40% of a car's energy at highway speeds. Traveling faster makes the job even harder...The increase is actually exponential, meaning wind resistance rises much more steeply between 70 and 80 mph than it does between 50 and 60. " 2) Engines are designed for specific speed, temperature, and rpm ranges. Driving out of these ranges goes against the fundamental design of the engine. I drove for several hundred miles on my return trip from the BMW Performance Center to home. I got my highest MPG (36) when I did not exceed 65 mph. I probably could have done better if I held the speed at 60 or below - but that is just too painful. I believe the absolute top economy is probably between 40 -50 MPH on flat roads, without headwind, and no stopping for traffic or red lights. |
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