Starting September 2011, the BMW Z4 Roadster goes through some changes under the hood. The new N20 four-cylinder TwinPower engine volition replace the inline-six unit constitute in the sDrive23i and sDrive30i models. The two new models volition be sold under the sDrive20i and sDrive28i badges. For more details on the upcoming changes, meet the press release below:

From autumn 2011, two model versions will exist equipped with state-of-the-art 4-cylinder petrol engines featuring BMW TwinPower Turbo technology. The new 2.0-litre engines are fitted in the BMW Z4 sDrive20i and in the BMW Z4 sDrive28i, which now replace the naturally aspirated six-cylinder BMW Z4 sDrive23i and BMW Z4 sDrive30i models.
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Combining improved efficiency and functioning with a simultaneous reduction in fuel consumption and emissions, the new 135 kW/184 hp and 180 kW/245 hp engines are as well lighter in weight thanks to an all-aluminium crankcase. This reduces the load on the front axle, for improved agility and handling. The BMW Z4 is equipped as standard with a six-speed transmission transmission, but optionally the new engines tin can exist combined with an eight-speed automatic manual. All models in the BMW Z4 range will in future feature Servotronic speed-sensitive power steering as standard.
The BMW Z4 sDrive 35i will also get 18-inch multispoke blend wheels. The popular roadster range will as well exist available with the new Pattern Pure Balance equipment package for extra styling enhancement. Exclusively in combination with this package, Mineral White metallic paintwork is available.

BMW Z4 sDrive28i and BMW Z4 sDrive20i with BMW TwinPower Turbo technology.

The new four-cylinder petrol engines are key components in the BMW EfficientDynamics strategy, which aims to combine increased driving enjoyment with reduced fuel consumption and emissions. Both versions are based on the aforementioned reduced-friction 1997 cc core engine, their different output ratings being due mainly to different injection and turbocharging engineering science. Cardinal features of the world-exclusive BMW TwinPower Turbo applied science include High Precision Injection direct injection, twin-scroll turbocharging, Double-Vanos variable camshaft timing and VALVETRONIC variable valve timing. These features give the new 4-cylinder engine the sort of power which in a naturally aspirated engine would require more cylinders and larger displacement. At the same time, with their all-aluminium crankcase, these engines are lighter and more meaty than a six-cylinder engine of equivalent ability. This has obvious benefits for driving dynamics: the reduced load on the front end axle results in greater agility and further improved steering and cornering characteristics.

More than dynamic performance, reduced fuel consumption.

In the version fitted in the new BMW Z4 sDrive28i, the 1997 cc four-cylinder engine develops maximum power of 180 kW/245 hp at 5,000 rpm, which is most a lucifer for the 190 kW/258 hp six-cylinder unit of measurement information technology replaces. And on torque it actually goes 1 amend. With elevation torque of 350 Newton metres (258 lb-ft) (+twoscore Nm / 29 lb-ft), which is available from 1,250 rpm, the new engine is noticeably more responsive. The lively power commitment from only above idle continues all the way into the higher engine load range. The resulting 0 to 100 km/h (62 mph) dispatch time for the BMW Z4 sDrive28i is but 5.6 seconds, which is 0.ane seconds faster than for the predecessor BMW Z4 sDrive30i (0.4 seconds faster for automated versions). The new iv-cylinder unit also offers better in-gear acceleration. Height speed remains unchanged at 250 km/h (155 mph).

Despite the functioning upgrade, the roadster also boasts essentially improved fuel consumption. Average fuel consumption for the BMW Z4 sDrive28i in the European union test bike has improved by an impressive one.seven litres – or xx per cent – to vi.viii litres/100 km (41.4 mpg imp). And there is a corresponding reduction in CO2 emissions, which now stand at 159 grams per kilometre.

The 4-cylinder engine fitted in the BMW Z4 sDrive20i is based on an identical core blueprint. Due to modified injection and turbocharging applied science, withal, this version delivers 135 kW/184 hp of ability at 4, 800 rpm, with elevation torque of 270 Newton metres (199 lb-ft) at 1,250 rpm. Despite a torque increment of xx Newton metres (14.7 lb-ft), this model too boasts a reduction in average European union fuel consumption of one.7 litres, or approximately 20 per cent, on its six-cylinder predecessor, the BMW Z4 sDrive23i, while delivering a 0-100 km/h (62 mph) sprint time of 6.9 seconds and a top speed of 235 km/h 146 mph).

Twin-gyre turbocharging.

The new four-cylinder engines also characteristic twin-curl turbocharging. This ways that the exhaust stream from cylinders 1 and 4, and the frazzle stream from cylinders 2 and iii, follow separate spiral-shaped paths to the turbine wheel. This reduces exhaust dorsum-force per unit area at low engine rpm, allowing the energy of the exhaust gas pulses to be utilised as efficiently as possible. The event is instant throttle response and typical BMW fast-revving performance.

Optional eight-speed automated transmission: more condolement, with no increase in fuel consumption.

The BMW Z4 sDrive28i and BMW Z4 sDrive20i are equipped equally standard with a vi-speed manual manual. Optionally, withal, drivers tin now leave the shifting to a new eight-speed automatic transmission which is very similar in terms of size and weight to the previous 6-speed unit. The two additional ratios provide an appreciable comeback in smoothness, sporty performance and efficiency. All automatic versions feature a sports steering wheel, which is equipped every bit standard with paddle shifts, so that the commuter can besides shift gears manually. The right-hand paddle is used for changing up and the left-paw paddle for irresolute downward. A restyled selector lever is standard with the eight-speed automated.

The new 8-speed automatic transmission features fast reaction and shift times, straight downshift adequacy, minimal torque converter slip and low friction losses, along with a broad ratio spread that has benefits both for sprinting functioning and for low-rpm cruising. The electronic transmission controller allows the shift characteristics to be altered equally required, to cater for a sporty or a more relaxed driving style. Improved overall efficiency means that the BMW Z4 with viii-speed automatic transmission offers identical fuel consumption and emissions performance to the corresponding manual version.
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New Design Pure Residual equipment parcel and exclusive Mineral White metallic exterior paint finish for the BMW Z4.

With the new Blueprint Pure Residue bundle, the BMW designers accept developed an elegant trim package tailored specifically to this popular roadster model. Information technology features an extensive leather interior, with the new Cohiba Brown shade and contrasting Lotus White stitching providing attractive highlights. The bundle is topped off by further leather trim elements in Black, with stitching in Umbra, plus Fineline Anthracite woods and standard-fitted sports seats.

For the get-go time the BMW Z4 volition be available in Mineral White metal, which is offered exclusively in combination with the new interior equipment package. Alternatively, the Design Pure Balance packet can also exist combined with other outside paint finishes. The new package replaces the previous "Pattern Pure White" parcel.