Fuel consumption

[Mercy1]

I've posted this question on this forum before, but I'm seriously dissappointed with the fuel usage on my 2010 C350 CDI sport estate, can anyone tell me why I can at the very best 36/37 mpg at between 70-80 mph when my pal gets 47 plus mpg with his E350 CDI doing the same speed, the only thing I can think of is it's a more efficient engine in the E as gearing is much the same.

If it's any consolation, I can tell you that your consumption sounds about the same as mine. I have no idea why the E class may be better, but I don't lose sleep over it. On a motorway, at just under 80 mph, I can get about 42 mpg if I drive with economy in mind (rarely!). As an experiment recently, I drove on a motorway for about 100 miles at a steady 60 mph and was amazed to see the OBC creep up to 52 mpg.
(I can tell you I didn't like the experience one bit, ducking and diving among juggernauts and coaches at the 60 mark and wincing as I was convinced overtaking white van men were going to take my rear wing off as they swept by! Lorries and coaches behind me were even catching up and flashing me! Didn't like it at all - much happier away from that lot in the proper Mercedes lanes!! Lol.)

 

[LTD]

Is the E-Class also an estate ?

So many factors present ...

Tyre pressures
Rolling resistance of tyres
Aerodynamics
Driving style
Gearbox settings
Cruise control present

Personally, use the smile (right) pedal as necessary and try to limit the brakes.

 

[donubenz]

Hi,My E class 320i saloon always gives better mpg when I use the cruise, I guess it is not so heavy footed as me! Average all roads is 35.4mpg after 16,000 miles and often indicates 47mpg after a motorway journey. (2000rpm at 70). No complaints apart from cost of fuel. I had a Ford Corsair 2 liter V4 in the 70's and could not get better than 20mpg!

 

[Xenon]

Just to put this into perspective, I collected my new E class 250CDI saloon 5 days ago. Today, I completed a 70 mile journey from Tunbridge Wells to Northwest London. Had the aircon on all the way since it was 30C today, and the M25 was its usual slow self with lots of start/stop traffic during rush hour. So what was my mpg? Well, the computer read 70 miles journey averaging 41mph and at 57.7mpg! I am soooooo pleased and hope that my mpgs will increase once the engine beds down with more mileage. I found my last E class 2010 model averaged around the mid forties. This new 2011 model is obviously a vast improvement.

 

[grober]

This from the Honest John site on the E Class saloon.

TSB on 220CDI reported by reader in January 2011 to replace a page in the driver's manual and to replace the tyre pressure sticker inside the fuel flap with a recommended pressure of 38PSI instead of 32PSI to improve fuel economy. Apparently fuel economy then improves by 10%, in the reader's case from 34mpg to 38.5mpg.


Have you compared tyre pressures on the 2 cars?

 

[st4]

Is the E-Class also an estate ?

So many factors present ...

Tyre pressures
Rolling resistance of tyres
Aerodynamics
Driving style
Gearbox settings
Cruise control present

Personally, use the smile (right) pedal as necessary and try to limit the brakes.

The estate e classes have a shorter final drive ratio apparently. My car has averaged 39.3 mpg over 7000 miles which is above combined. Returning from cornwall mpg at 70 MPH was lower at only 43 on motorway but it was full up. Marvelous way of traveling. Rolling resistance of tyres plays a part. Energy savers on front used to add a few mpg to mine over the conti sport 3s

 

[Adam230K]

Why?? I had been showing over 47MPG until I went 3 miles down country lanes.

Sorry I meant 47 mpg average sounds wrong

 

[fah320]

Sorry I meant 47 mpg average sounds wrong

I did an experimental drive; steady 90 km/h and got down do 4,7 l/100 km. Maybe it could do lower but I was bored...

 

[Adam230K]

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I did an experimental drive; steady 90 km/h and got down do 4,7 l/100 km. Maybe it could do lower but I was bored...

Yeah so you won't average 4.7l/100km because you will be too bored to continue driving like that.

Have no doubt that the car is capable of that mpg, but to consistently achieve that mpg throughout all driving conditions is just wishful thinking.

I achieve 55mpg average in my 1.4tdi and I drive it like I stole it. It can acheive 70mpg, but i've never averaged it because its just too boring and lethargic.

average is the key word here!

 

[fah320]

Yeah so you won't average 4.7l/100km because you will be too bored to continue driving like that.

Have no doubt that the car is capable of that mpg, but to consistently achieve that mpg throughout all driving conditions is just wishful thinking.

I achieve 55mpg average in my 1.4tdi and I drive it like I stole it. It can acheive 70mpg, but i've never averaged it because its just too boring and lethargic.

average is the key word here!

I agree, in city I dont drive agressive and can get an avarage of 40mpg and I can get the same in highway with my normal driving; around 110-130 km/h(75-80 miles/h.
I ignore consumption when I drive agressive and at high speeds because in this case performance is what you need not economy.
Despite the fact that I drive slower in city and my route has just a few traffic lights and I can drive at 45-50 miles/h most of the times consumption is higher because every morning and evening the car starts with cold engine. I think cold engine is the killer for consumption....

 

[Xenon]

I agree with *** that tyres can make a big difference. My last year's e class came with Bridgestones. (You seem to get whatever tyres Mercedes has lying around for their new cars). Whereas, my 2011 E class came with Pirellis. Not only do I believe it has improved my mileage, but the ride is much better and quieter. Would be interested to know what other's opinions are regarding their tyres and mileage/comfort. Doesn't seem to be a tread on this, yet.

 

[gina2201]

Don't know what the A class does to be honest , it hasn't got anything as fancy as a trip computer.

I'm surprised the 202 hasn't got one either....most annoying!

Best I've got is 37mpg Birmingham - Plymouth
Around town 21-23mpg

The RR was not far from that - I assumed this would be better?

 

[Adam230K]

My sh1tty polo has a trip computer....!

 

[Shude]

I'm surprised the 202 hasn't got one either....most annoying!

You can retrofit a 208 or 210 instrument cluster if you want the trip computer (also steering wheel and airbag - about the same money as 10 trips to the pumps ).

Best I've got is 37mpg Birmingham - Plymouth
Around town 21-23mpg

The RR was not far from that - I assumed this would be better?

C230k? Might as well hammer it everywhere as it makes almost no difference! You have to imagine it puts out about the same power as a V6 C280 but when it's idling it's just a little 4-banger

 

[Oli]

I'd love to see these sort of miles per gallon ...

27-29 on motorways , 15-17 around town for me

Same for me, 15-18 in town(18 is driving like a grandma) and the highest I've had on the motorway is 25.