German tuner dials up power on the BMW 550i and converts the Z4 to an 320d Efficient Dynamics-influenced diesel-sipper.

German tuner AC Schnitzer has previewed two new models ahead of their Geneva debut.

The ACS5 Sport S and ACS 99d are based on the BMW 5-Series and Z4 models, respectively. The aim of the Aachen-based tuner with these two models is to create power and performance while still keeping an eye on fuel-economy and emissions.

The ACS5 Sport S is based on the BMW 550i model and dials up the noise on the 4.4 liter V8 to 540 PS (397 kW / 532 bhp) and 750 Nm (553 lb-ft) of torque from the series' 407 PS (300 kW/ 401 bhp) and 600 Nm (442 lb-ft). The 0 to 100 km/h sprint takes just 4.5 seconds and top speed is 320 km/h (198 mph).

Even with more than 130 additional horses, the ACS5 Sport S has the same fuel-economy and emissions rating as the standard 550i.

AC Schnitzer works the same tuner magic on the Z4-based 99d to which it adapts a conversion kit inspired by the 320d Efficient Dynamics edition. The 2.0 liter diesel power plant is good for 190 PS (140 kW / 188 bhp) and 420 Nm (310 lb-ft) of torque with a 0 to 100 km/h sprint time of 6.9 seconds and a top speed of 235 km/h.

Fuel-economy for the 99d is an impressive 3.8 liters/100 km (besting the 320d ED) and CO2 emissions are 99 g/km. AC Schnitzer makes those numbers by means of a 230 kg reduction in weight.

We assume they use the same modus operandi on the 550i but the press release didn't say.

More details will follow with the Geneva premiere.

Gallery: AC Schnitzer premieres the ACS5 Sport S and ACS 99d [videos]

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