Fuel Economy New 3.0D and 3.0SD

[glenine]

Looking at the BMW figures for Urban and extra urban for the 3.0D and twin turbo the figures look remarkably similar. At first I thought that by buying a SD you could have much better performance for a 2% decline in fuel economy, ie a win win situation. However talking this through with my local dealer he said the fuel measurements do not reflect day to day driving. In theory they are similar provided you don't make heavy use of the accelerator, but this is probably not realistic.

To back this up I looked at the Autocar's test results for the 5 series 3.0d and 535d (ie very similar engines as X5) and found that they got 33.6 and 27.7 respectively against BMW's own urban cycle for these cars of 32.8 and 31.4.

Therefore extrapolating these figures to the new engines on the X5 I estimate that a realistic day to day figure for the 3.0D will be 28.5 and 24 for the SD. I would be interested in other peoples thoughts on this.