Vehicle fuel economy calculation WAY OFF
Thread Starter
Senior Member
Joined: Apr 2004
Posts: 463
Likes: 145
From: Toronto, Canada
2023 GLE63S - Edition 55
Vehicle fuel economy calculation WAY OFF
I just tested my new 2015 ML350 Bluetec on a couple highway trips (200 miles). I was happy to see the vehicle reporting an average of between 30-32 MPG. After re-fueling at the end of the trip and doing the actual calculation based on distance travelled/fuel added it worked out to 22-24 MPG. Thats a pretty big difference ! Has anyone experienced something similar?
Member
Joined: Oct 2013
Posts: 224
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From: Western Europe
2017 GLS 350d
I did it at the beginning (like 2 years back) and I remember actual consumption was always slightly worse than onboard computer one, but never by more than 10%. Nothing compared with the type of difference you got!
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Joined: Dec 2006
Posts: 161
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From: Endicott NY
2014 ML350 Bluetec, 2016 GLC 300, 2023 Corvette, Z51 Stingray
Just picked up a 2014 ml350 BT with only 7k. Did a round trip of 650 miles. My calculation after a filling up was dead on compared tot the computer.
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Joined: Feb 2006
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2014 ML 350 bluetec
I just tested my new 2015 ML350 Bluetec on a couple highway trips (200 miles). I was happy to see the vehicle reporting an average of between 30-32 MPG. After re-fueling at the end of the trip and doing the actual calculation based on distance travelled/fuel added it worked out to 22-24 MPG. Thats a pretty big difference ! Has anyone experienced something similar?
I don't know where you got the average of 30-32.. that is VERY high.
if you go on the fuelly web site, average reports are between 22-24mpg.
My best was about 25mpg (9L/100) all highway driving at 70+mph.
If you drive at around 50mph, you can get some 30+ mpg.
i always log my fuel and compare to computer. The computer is off by about 8-12% (it shows a better fuel consumption by 8-12%)
Thread Starter
Senior Member
Joined: Apr 2004
Posts: 463
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From: Toronto, Canada
2023 GLE63S - Edition 55
Interesting .... I guess my real calculated numbers are about right then as I was travelling at around 75-80 MPH and still got 22-24 MPG. Not sure why my computer is off by such a large margin.
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Joined: Oct 2013
Posts: 224
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From: Western Europe
2017 GLS 350d
You wouldnt by any chance have reset the computer mid trip and it would show you only the part of the trip you did at constant speed for example?
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Joined: Nov 2012
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From: Alberta, Canada
ml350 bluetec
I can tell you that my '13 350 BT, gets 37.8 miles to the US gallon at 48 mph (with cruise control) on a dead flat road. Why? I had a flat & was using the spare that has a 50 mph max. The sixty mile trip, there and back was exceptionally boring. Why did I go that far? I was told that somewhere in that town, someone could fix the flat. They could not, or they could but they would wreck the rim. Got it fixed the next day in the place I was staying, and it was fixed & mounted for free. Yeah Dillon, MT! An extremely friendly town with the best Mexican food I have ever had.
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Senior Member
Joined: Sep 2012
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From: Ottawa ON Canada
2015 ML350 Bluetec
Chris, I see you're from Toronto... Is it possible you were using the wrong formula and looking at Imperial Gallons instead of American Gallons? or vice versa? To lazy to verify the formulas, but there is a difference!
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Senior Member
Joined: Apr 2004
Posts: 463
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From: Toronto, Canada
2023 GLE63S - Edition 55
Funny you should say that.... Last night I did the conversion on my laptop and got what appears to be the exact right number. When I made the post, I had converted it using my phone and very likely used the wrong conversion method. I think its all good now. I recall the initial conversion that I used 10l/100 was about 28 MPG. I know that was very wrong now, more like 24
Last edited by chrislk55; May 1, 2015 at 08:53 PM.
