BMW regenerates Z4

BMW has introduced running changes to its recently released second-generation Z4, with Australian customer deliveries commencing from this month.

Designed to improve fuel efficiency and cut carbon dioxide emissions, BMW’s new Brake Energy Regeneration (BER) system contributes to a claimed eight per cent slide in the former category and about a four per cent fall in the latter.

Low rolling resistance tyres have also been introduced on the sDrive23i entry-level Z4 as another fuel saving measure.

Both come under the company’s EfficientDynamics mantra that has seen a raft of eco measures applied selectively on an increasing number of BMWs sold in Australia.

The upshot is a 7.8 per cent improvement in Z4 sDrive23i fuel consumption, translating to 0.7 litres per 100km on the combined average cycle (8.2L/100km versus 8.9 in the automatic and 8.5L/100km instead of 9.2 in the manual).

A 7.6 per cent drop applies in the MY10 Z4 sDrive30i (8.3 and 8.5L/100km against 9.0 and 9.2L/100km for the auto and manual versions respectively), while the range topping twin-turbocharged Z4 sDrive35i’s 0.4L/100km saving (now 9.0L/100km for the auto and 9.4L/100km in the manual) represents a 4.2 per cent improvement.

Likewise the cuts to CO2 emissions are of a similar magnitude, averaging to about 15 grams per kilometre (or about 196g/km) in the normally aspirated Z4s, while the Z4 sDrive35i’s 210 and 219g/km ratings for the auto and manual are a 9g/km shave.

The company says the benefits occur because of the selective application of the MY10 cars’ new alternator application, which sees it now operate only when the engine is on overrun or when the brakes are applied, thus reducing engine load and power uptake.

It brings the BER tally to 30 BMWs overall, leaving the X5 range as the only model not to offer it on at least one variant. However, this situation is expected to alter, so to speak, within the next few months, for the North American-built SUV.

BMW hopes the MY10 Z4’s BER measures will provide a compelling reason for sportscar buyers not to gravitate towards Audi’s popular TT, which has taken the fuel consumption high ground since the TDI quattro diesel version was added to the range in the middle of this year.

While Z4 sales for 2009 are nearly double that of last year’s amount thanks to the introduction of the new-generation E89 model in May, the BMW still trails the Audi significantly, even though the latter has seen TT volume plummet by 35 per cent against last year’s numbers.

Year-to-date figures to October reveal 225 Z4s sold against 556 TTs. Over the same period Mercedes-Benz found 274 homes for the rivalling SLK – which is a 13 per cent stumble over the same period in 2008.