BMW Z4 roadster (2009-2016) - MPG, running costs & CO2

The BMW Z4 has plenty of economical petrol engines, but no diesel option

Carbuyer Rating

2.9 out of 5

MPG, running costs & CO2 Rating

3.2 out of 5

BMW's decision not to offer a diesel version of the BMW Z4 means there are no super-frugal models, but fuel economy is good when you consider the weight of the car and the performance on offer.

The Z4 isn't cheap to buy, but it does undercut rivals such as the Mercedes SLC and Porsche 718 Boxster. And while smaller two-seater sports cars such as the Mazda MX-5 are cheaper, they don't offer the same luxurious feel as the BMW.

We also expect the BMW to have strong residual values on the used car market – the sDrive18i and sDrive20i should hold on to over 50% of their original value after three years, with only the more powerful (and expensive) models falling below that.

BMW Z4 MPG and CO2

Even the basic Z4 sDrive18i's 2.0-litre petrol engine makes it pretty quick, while returning up to 41.5mpg fuel economy and emitting 159g/km of CO2 for annual road tax of £185.

The next model up – the sDrive20i – matches these figures, while giving noticeable extra performance. The sDrive28i is faster still, yet remarkably returns the same fuel economy figures and emits the same amount of CO2.

The sDrive35i is much faster than any of them, however it's also more expensive to run, with fuel economy dropping to 30.1mpg and CO2 emissions jumping to 219g/km. Road tax here is £295 a year.

The top-of-the-range BMW Z4 sDrive35is, is (strangely) faster than the sDrive35i but more economical. That's thanks to BMW's seven-speed automatic gearbox, which is fitted to this model as standard. This has an extra gear to boost economy while cruising, allowing the car to return 31.4mpg. CO2 emissions fall to 210g/km, although this makes no difference to the road tax rate.

Insurance group

The Z4 isn't cheap to insure, with all models falling into groups 33 to 43. This is only marginally better than the Porsche 718 Boxster and Mercedes SLC.


BMW offers a three-year/unlimited-mile warranty on its range, and you can extend this for an additional cost.

Service costs

For the best peace of mind, paying in advance for BMW Service Inclusive covers your car’s servicing requirements for five years or 50,000 miles, whichever comes first. This costs £525 for the Z4. A more comprehensive package that covers maintenance such as changing the brakes will cost you £1,470.

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