Car in 2011: AC SchnitzerCar in 2011

AC Schnitzer has prepared two production ready concept cars for this year's edition of the Geneva motor show. We've already told you about the first car, the diesel-powered 99d that is based on the BMW Z4 roadster, so here's the tuning firm's second proposal. The ACS5 Sport S Saloon is based on the latest BMW 550i sedan and is said to feature numerous performance and styling upgrades, though AC Schnitzer is keeping mum about most of the details.

According to the tuning house, the 550i's twin-turbocharged 4.4-liter V8 engine with 407HP and 600Nm has been modified to deliver 540HP and 750Nm, which helps the sedan model to complete the 0 to 100km/h (62 mph) sprint in 4.5 seconds and reach a top speed of 320 km/h (199 mph). AC Schnitzer said that despite the power bump, fuel consumption and CO2 emissions of the ACS5 Sport S are equivalent to the standard BMW 550i.

_______________________________GALLERY_______________________________

BMW's decision to create the new 'i' sub-brand for the growing number of eco-conscious buyers has apparently rubbed off its partners like AC Schnitzer, as the German tuning firm will be launching a production ready concept based on the Z4 hardtop-roadster at next week's Geneva motor show.

Developed as an eco-friendly sports car that adapts to AC Schnitzer's new motto "Efficient Performance", the 99d gets its name from its CO2 emission levels and the diesel powerplant housed under its hood.

More specifically, the tuning house fitted the Z4 with the BMW 320d Efficient Dynamic's 2.0-liter four-cylinder turbocharged diesel engine. After some performance upgrades, the four-pot's output was lifted from 163HP and 380Nm, to 190HP and 420Nm.

AC Schnitzer says the 99d can go from naught to 100km/h (62mph) in 6.9 seconds en route to a top speed of 235km/h (146mph), while returning an impressive fuel consumption of 3.8lt/100km (61.9 mpg US) with CO2 emissions of just 99.18 g/km.

To achieve these striking numbers, the German tuner also reduced the roadster's weight by 230kg (507 pounds).

"With the AC Schnitzer 99d, we've succeeded in building the previously inconceivable: an up-rated performance vehicle whose CO2 emissions have been reduced to 99 g/km and which, despite its sustainability, offers pure driving pleasure. That's Efficient Performance by AC Schnitzer," the company said in a brief statement.

According to the tuner, the price of the 99d is €149,000 or about US$205,500 at today’s exchange rates, but that's about all the details AC Schnitzer is willing to release before unveiling the car at the Geneva Salon.