C350CDI First fuel up... 29.9 mpg

[ndps]

A little shocked at my first full brim to brim tank. Guess I need to wear some lighter shoes! Having fun though...

After reading some of the other posts on here I wasnt expecting massively high numbers, but considering more than half the miles covered on this tank were on a single motorway cruise I would have expected more.

Maybe I need to cut out the lunchtime B-road detours

 

[crockers]

NEVER seen figures that low.......

 

[AJA]

Having fun though...

Keep up the good work

 

[@MARK]

Nice to see you running it in properly

but considering more than half the miles covered on this tank were on a single motorway cruise

But you don't say how fast you were cruising

Also how do you know it had 50.8 litres of fuel in when you picked it up?

 

[A210AMG]

I get 28mpg towing our caravan

 

[Meldrew2]

NEVER seen figures that low.......

Try my ML350...... never seen figures that HIGH !!

 

[wemorgan]

Does your car give the instantaneous mpg read out? Good overall mpg figures are slow to produce but disappear quickly with a heavy right foot.

But it sounds like you're enjoying your car....so keep up the good work.

 

[ndps]

But you don't say how fast you were cruising

I set the cruise control to 75 for most of it, OBC mpg was reading in the 40's. However on the way back I got a little bored and didnt drive as smoothly, the torque is too addictive for overtaking!

Also how do you know it had 50.8 litres of fuel in when you picked it up?

That was the first fill I did after getting the car, when the odometer was on 99 miles (it came with about a quarter of a tank).

 

[ndps]

Does your car give the instantaneous mpg read out? Good overall mpg figures are slow to produce but disappear quickly with a heavy right foot.

Annoyingly it doesn't seem to have a numerical instantaneous read out, only a bar reading which max's out at 40mpg!
You can do a journey average or a resettable trip average, and theres also a minute by minute bar chart display on the comand. I am not sure why they didnt include it, its not as if the information isn't there!

 

[wemorgan]

Never mind day time running lights, I think all new cars should give the instantaneous and average mpg readout. I'd hope owners would be interested to know these figures and maybe even change their driving style from time to time.

 

[corned]

I think all new cars should give the instantaneous and average mpg readout.

As I've posted before, Jaguars have done that for nigh on the last 40 years...

 

[st13phil]

My guess is that it wasn't really "brim full" when you filled it the time before.

When I had my W204 I found that the amount of fuel you could get in was dependent upon the attitude of the car, i.e. on a slope front to rear or side to side. Did you fill up both times at the same pump on the same forecourt?

 

[steve333]

A little shocked at my first full brim to brim tank. Guess I need to wear some lighter shoes! Having fun though...

After reading some of the other posts on here I wasnt expecting massively high numbers, but considering more than half the miles covered on this tank were on a single motorway cruise I would have expected more.

Maybe I need to cut out the lunchtime B-road detours

Out of interest what did assyst show for your brim to brim mpg?

 

[ndps]

My guess is that it wasn't really "brim full" when you filled it the time before.

When I had my W204 I found that the amount of fuel you could get in was dependent upon the attitude of the car, i.e. on a slope front to rear or side to side. Did you fill up both times at the same pump on the same forecourt?

It was the same forecourt, two pumps over so the conditions would be very similar.

Out of interest what did assyst show for your brim to brim mpg?

I had reset the average mpg counter a few times over the last few days playing around with it. Not sure there is any other way to log a brim to brim mpg on the OBC other than using the average mpg counter and resetting every tank fill?

 

[steve333]

It was the same forecourt, two pumps over so the conditions would be very similar.



I had reset the average mpg counter a few times over the last few days playing around with it. Not sure there is any other way to log a brim to brim mpg on the OBC other than using the average mpg counter and resetting every tank fill?

Sorry, what i meant was had you reset the obc before doing the brim to brim manual calculations to see what difference there was-i.e. how accurate is the obc reading?

 

[John]

I think all new cars should give the instantaneous and average mpg readout. I'd hope owners would be interested to know these figures and maybe even change their driving style from time to time.

My first E36 325i back in 1999 had an instantaneous mechanical MPG meter beneath the speedo.

Watching it made grim viewing - it seemed to be in single figures a lot when I wasn't even driving hard - although granted they weren't the most fuel efficient.

 

[ndps]

Sorry, what i meant was had you reset the obc before doing the brim to brim manual calculations to see what difference there was-i.e. how accurate is the obc reading?

No, I don't currently have a comparison. I will keep the OBC average mpg counter unreset for this whole tank to see what the difference is.

 

[@MARK]

I set the cruise control to 75 for most of it, OBC mpg was reading in the 40's. However on the way back I got a little bored and didnt drive as smoothly, the torque is too addictive for overtaking!



That was the first fill I did after getting the car, when the odometer was on 99 miles (it came with about a quarter of a tank).

You need to go into Fuelly and set the miles to 99 (you can edit fill ups) then for that first fill up otherwise your average will be skewed for quite some time.

 

[ndps]

You need to go into Fuelly and set the miles to 99 (you can edit fill ups) then for that first fill up otherwise your average will be skewed for quite some time.

Yeah I put in the odometer reading of 99 miles when I entered it in. Now on 489 miles, so it has calculated the mpg correctly.

 

[Red C220]

Sorry, what i meant was had you reset the obc before doing the brim to brim manual calculations to see what difference there was-i.e. how accurate is the obc reading?

I reset the OBC every fill and record the mileage. I've never had the compulsion to do this with any other car I've owned so I'm not sure why I've started now!

Anyhow, after 7 tank fulls I find the OBC to be consistently 10% to 15% optimistic.