best mph for mpg motorway driving

SquabzZz

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Hey people

what motorway speeds do you find your car at its best MPG (state what mercedes too)

I cant drive at 60mph its just too slow :D

C Class Coupe 220 CDI 7G

at 72 mph i get around 54 mpg
 

AMGeed

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Took a 191 mile round trip to Heathrow yesterday and due to the extensive road works for 20 odd miles at a 50mph limit from Fleet to the Heathrow turn off, I finally managed my best ever fuel consumption on a run.
191 miles at an average of 62mph and 24.8mpg. The car (E55) seems to be at its optimum at around 70mph I noticed. Pity I didn't photograph it for posterity
 

tec

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56-60 MPH is supposed to be the best for MPG.

I don't drive for economy, so 50MPG is not something I will ever achieve in current car.
 

Mr Kripling

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The best I've had was with the Distronic set to 70mph where I achieved 28.6mpg over 51 miles...
 

Bellow

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I think this was answered concisely by Dieselman IIRC some time back - the slowest speed top gear will permit. Whether that is an acceptable speed is another question.
 

Driver15

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Not a merc... buy my BMW E60 525d, 67mph average will return 54 mpg not problem.

MPG for the 50MPH specs on the M1 can result in 60 MPG for the full section.

Add X amount to the above average and the magic number is always 38.7MPG.
 
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SquabzZz

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so its safe to say anything over 50mpg is good :D
 

MancMike

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Tec is right, Lorries cruise at 56 for similar reasons. It's the most speed you can attain before the air gets too thick and the extra distance you cover is disproportional to the drag created.

For me, I can manage 35mpg if doing 55-56mph (on sat nav, about 57mph, 58mph on the cruise). If I draft as big a lorry as I can find, I can eek it up to 39mpg. (obviously getting too close gives far better mpg but is stupid).

If I drive a proper speed, 70~80, then I get about 28mpg.
 

Hawkwind

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Brighton to Heathrow 36mpg, speed never over 70mph and reduced to about 55mph for last 15-20 miles (was very early, so thought I'd slow down and save some juice).

Normally average about 32 with speeds of up to 80mph. CLK320 convertible.
 

Jonesy161

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W204 c220 sport
Mixed driving is currently 48mpg, motorway at 70 is 58 mpg, motorway in average speed zone at max 50mph is 64 mpg but sole destroying.
 

SLKGirl

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Best I've had is 37mpg on motorway @ 70mph, generally I get around 35mpg and worst is 30mpg
 
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SquabzZz

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Mixed driving is currently 48mpg, motorway at 70 is 58 mpg, motorway in average speed zone at max 50mph is 64 mpg but sole destroying.

50 mph would take forever for me to get to my destinations

So your blue efficency averages an extra 4 mpg at the same speeds
 

renault12ts

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Tec is right, Lorries cruise at 56 for similar reasons. It's the most speed you can attain before the air gets too thick and the extra distance you cover is disproportional to the drag created.

For me, I can manage 35mpg if doing 55-56mph (on sat nav, about 57mph, 58mph on the cruise). If I draft as big a lorry as I can find, I can eek it up to 39mpg. (obviously getting too close gives far better mpg but is stupid).

If I drive a proper speed, 70~80, then I get about 28mpg.

I think lorries cruise at 56...because they can't go faster.
 
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It was enough of a concession to buy a diesel in the first place, I'll be buggered if I'm going to drive slow as well.
 

johns E350

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The best I have ever got was 49.4. I just could not get it to the magic 50 was not all motorway driving though
Car E350 CDI coupe
 

KennyN

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Recently I did an 850 mile trip in my CLS 350d , averaged 44 mpg for the entire trip.

First 425 mile leg was done without stopping , return leg there was one stop involved - for diesel.

Average speed was around 60 ish mph IIRC for the entire trip.

Kenny
 
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SquabzZz

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Recently I did an 850 mile trip in my CLS 350d , averaged 44 mpg for the entire trip.

First 425 mile leg was done without stopping , return leg there was one stop involved - for diesel.

Average speed was around 60 ish mph IIRC for the entire trip.

Kenny

them 350 diesel engines are a beaut :thumb:

lots of power and economical when you need them to be
 

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