Sportsters get 'efficient dynamics' to boost economy, cut CO2
23 August 2007

BMW is expanding its eco-friendly 'efficient dynamics' to the Z4 roadster and coupe.Already used in the 1-series, 3-series and 5-series, 'efficient dynamics' aims to save fuel and reduce emissions without compromising agility.Whereas BMW's existing systems are predominantly focused around regenerative braking and combined alternator/starter motor units, the Z4 uses a new, more efficient rear axle transmission.This 'friction optimised' rear axle lowers CO2 outputs and increases economy for all six-cylinder Z4s except the Z4M. The 2.5si goes from a combined economy of 33.6mpg to 34.0, with CO2 output down from 202 to 199g/km. The 3.0si goes from 32.8 to 33.2mpg and 207 to 204g/km, and the 3.0si coupe from 31.7 to 32.5mpg and 213 to 207g/km.The 2.0-litre four-cylinder engine has also been made more efficient, with CO2 dropping from 181 to 176g/km and mpg rising from 37.7 to 38.2.The changes apply to all Z4s built from 1 September 2007. They're not huge changes, granted, but we reckon they're still significant.

Our Verdict

The BMW Z4 has more comfort and added practicality, but has it gone soft?

The BMW Z4 is a fine-looking two-seat roadster with indifferent driving dynamics

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