2008 220CDI fuel economy

[diesel demon]

I have recently purchased a 2008 220cdi Saloon and i'm averaging around 47mpg on the run in to london which is mostly motorway and dual carraigeway driving. If i drive at 56mph in 6th gear and i reset the trip/mpg settings i only get around 50mpg so i'm wondering if there is a problem with the car as MB claim 60mpg @ extra urban. Any ideas welcome.

 

[artyman]

What MB claim and what you actually get are two different things. I'm a light footed driver and always exceeded manufacturers figures in my Ocatvia, but only average about 40mpg from my C200cdi

 

[Rory]

If i drive at 56mph

Extra-urban average speed is 39MPH.

 

[diesel demon]

thanks for the info. So what gear would that be in? surely not 6th!

 

[diesel demon]

got it now-Extra-urban fuel consumption (mpg) defined as: The extra-urban cycle is conducted immediately following the urban cycle and consists roughly half steady-speed driving and the remainder accelerations, decelerations and some idling. Maximum speed is 75mph (120 km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3 miles (7 km).

 

[Rory]

If i drive at 56mph in 6th gear and i reset the trip/mpg settings i only get around 50mpg

Does the MPG increase the longer you drive like that?

Mine takes 100 miles on the motorway before the MPG peaks and I then get to a point where the slightest uphill gradient will knock .1 or .2 off and then easing it downhill it will recover the lost MPG. At 70-75 it'll settle at 52MPG but the *slightest* urgency will knock 5MPG off that.

I have to say if indicated 50MPG at 56MPH in 6th is the best you can get, especially bearing in mind it's a manual, then I'd be a bit disappointed with that. Wonder how accurate the reading is? - it doesn't measure MPG at all, it calculates it from injection pulses.

I always wonder if these cars can be "tuned" at all - I don't mean chipped or remapped, but whether the injector timing could be adjusted.

 

[crockers]

Don't forget all those tests are done on a rolling road - minimal fuel level, no wind resistance etc etc. They are designed for one purpose only - to compare cars and are not what one can expect. Also the claimed CO2 levels and what your car actually produces are very different too.

 

[diesel demon]

I must admit i haven't taken it for a long run at 56mph and I have noticed too that if you start to climb and gradient, the MPG starts to drop off quite noticeabley. On the run to work this morning it returned around 53.6 MPG on a 45 mile run averaging around 40mph. I think from what you are saying, it needs a good run before the MPG starts to stabilise. Does anyone know at what RPM the turbo kicks in. I guess if you change gear before this but keep the engine in the torque band, that should help with efficiency.

 

[diesel demon]

I must admit i haven't taken it for a long run at 56mph and I have noticed too that if you start to climb and gradient, the MPG starts to drop off quite noticeabley. On the run to work this morning it returned around 53.6 MPG on a 45 mile run averaging around 40mph. I think from what you are saying, it needs a good run before the MPG starts to stabilise. Does anyone know at what RPM the turbo kicks in. I guess if you change gear before this but keep the engine in the torque band, that should help with efficiency.

Used the car for a year or so now and the run in to East London each day returns around 53mpg. What a car.

Sent from my iPad using MBClub UK

 

[Troon]

diesel demon - you need to be clear your car is a C220CDI.

Welcome,

 

[diesel demon]

Noted with thanks.

 

[mersum1es]

Don't forget all those tests are done on a rolling road - minimal fuel level, no wind resistance etc etc. They are designed for one purpose only - to compare cars and are not what one can expect. Also the claimed CO2 levels and what your car actually produces are very different too.

Yep, manufacturers are competing together, and for example taxes (both annual and purchase price) are calculated according these CO2 announced by manufacturers. Here is test done by one major Finnish car/tech magazine, and how reality is different (via google translator):
Google Translate

Edit: result is that there may be up to 40% optimistic values in official readings.

 

[Rory]

They are working on changing the tests to make them more "real world" but it's reckoned it could be 2020 before they're implemented as it is has to internationally agreed.

The irritating thing with the current tests is that the error isn't consistant - some cars can do their official figures in real life but others are way off.