Volvo C30 DRIVe: Fuel for thought

Computer mpg v paper and pen

I have an unhealthy obsession: I am on-board computer mpg addict. There I've said it.

At Parker's I get to test a fair number of cars on a short-term basis and before I climb aboard every vehicle I am thinking about the location of the switch or lever that allows me to view the average and ongoing fuel economy figure. I get in turn the key and start my search - that's even before I have programmed in my favourite radio station.

I behave in a similar fashion when I get behind the wheel of my Volvo C30 DRIVe long-termer. For two months I have not let my obsession with mpg wane.

A couple of turns on the steering column-mounted stalk allows me to view the average fuel economy within seconds and by clicking the rotating dial one notch forward I can see the state of my ongoing fuel economy - oh the pleasure of seeing a 99mpg reading as I release my foot off the throttle as I go downhill.

Sad isn't it?

The reason I obsess about on-board fuel economy readings is because I'm a cynical git. I love conspiracy theories and I'm quite sure the on-board mpg readings - on all cars - are wrong. The Volvo C30 DRIVe, with all its eco-credentials, is no different.

Throughout my two-month ownership the average on-board economy has shifted slowly but surely downwards as my driving has become increasingly frenetic. I'm testing it, you see.

The average official mpg on this model should be 74.3mpg and to me that's hugely unrealistic in real-world conditions. So it has proved: the onboard computer has never highlighted anything near that. In the first two weeks the average fuel consumption read 50.5mpg. Now, two months on, it reads 48.7mpg. The daily 75-mile commute up and down the A1 has taken its toll.

But, like every good and committed car journalist I've been logging the fuel use by using good old fashioned pen and paper. In the first week I was averaging a rather paltry 44mpg (after logging the mileage on a full tank), which rose to high of 48.31mpg. Then it dropped back to 45.24mpg and after the last fill-up it increased to 45.31mpg. Over the two-month period average mpg is 45.7mpg - 3.1mpg less than the computer reading.

I think the pen and paper beats the computer hands-down as an mpg calculator - let's see if the two become one in the months to come.


Compare compeitors' fuel economy. Check out mpg for the Ford Focus Econetic, the SEAT Leon Ecomotive and the BMW 1-Series 118d SE 3dr.

Current mileage: 5630

Average mpg: 45.7