BMW lightens 7 Series, but bulks up on tech

  • 21-Sep-2015 02:10 EDT
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The 2016 BMW 7 Series' slippery new exterior suffers 15% less aerodynamic drag than its predecessor. (Dan Carney)

Prestige car manufacturers are trading body blows among their top-segment models, with each ladling on more lavish content and more cutting-edge technology with each new introduction.

So it was for BMW at the 2015 Frankfurt Motor Show, where it pulled the cover off its 7 Series and released it to take on the Mercedes-Benz S-Class and Audi A8. We may not have yet reached the day when carbon-fiber chassis seen in sports cars have proliferated among these sedans, but the 2016 7 Series offers a step in that direction with a chassis featuring significant carbon-fiber reinforcement to a mostly steel structure. BMW terms this hybrid materials approach “carbon core.”

The car’s doors and trunk lid are aluminum, and use of that metal in the suspension, brakes, and wheels slashes unsprung weight by 15%.

“Its innovative combination of carbon-fiber structures with steel, aluminum, magnesium, and plastic means that the 750i xDrive is 130 kg (287 lb) lighter than the previous model,” noted Klaus Frolich, BMW Board Member for Research and Development. “Lightweight design measures adding up to roughly 200 kg (440 lb) have enabled us to integrate additional comfort and safety features,” he said. “This ensures that the 7 Series is the lightest luxury sedan in its segment.”

Outside, the body shell is smoothed and airflowed aided by active measures such as grille shutters, an “air curtain” that steers airflow past the side of the wheel arch, while “air breathers” direct air into the front wheel arches through vertical intakes in the front fenders. These measures, along with a sealed underbody, contribute to a 15% reduction in aerodynamic drag.

Front and rear self-leveling air suspension lets drivers manually raise the car by 20 mm (0.8 in) when approaching steep entrances and automatically lowers is by 10 mm (0.4 in) when driving at highway speeds for reduced drag.

An active anti-roll bar is a feature increasingly seen on SUVs because it permits disconnection for wheel articulation when driving off road, then returns to its normal function of reducing body lean in turns on road. The new 7 Series uses one so it can disconnect the bar when the car is driving in a straight line to let each corner’s suspension respond to bumps individually, without affecting the others. When turning, the anti-roll bar returns to its normal function.

The 7 Series also has a variable ratio steering rack and active rear steering, which combine to provide improved maneuverability.

What else? How about remote control self-parking? “This means the vehicle can maneuver itself in and out of a garage or parking spot without the driver behind the wheel,” Frolich explained. The driver will use BMW’s new Display Key, which appears to combine the appearance of a small smartphone with functions such as starting, the car’s lock status, and even service notifications. Remote-control parking will not be available when cars reach dealers this fall, but is scheduled to follow soon afterward, he added.

Frolich boldly invited customers to try the 7 Series’ new gesture-control system, an interface for the car’s infotainment systems that reads the driver’s gesticulating in its direction and interprets that to control functions like radio and phone. Considering the mixed record of voice command systems and BMW’s iDrive interface, it is worrisome to consider what gestures the computer system might induce.

BMW continues to refine its signature iDrive infotainment interface, finally combining touch screen inputs with its control knob despite a decade of insisting that fingerprints make touch screens undesirable.

A Bowers & Wilkins Diamond surround sound system features a 10-channel, 1400-W amplifier and 16 speakers to immerse occupants in sound. Meanwhile a new headup display projects information for the driver with an image on the windshield that is 75% larger than the previous system, with improved image quality and detail.

BMW has announced three U.S. gasoline drivetrains for the 7 Series; a 445-hp (332-kW) twin-turbo 4.4-L V8 for the 750i, a 320-hp (239-kW) 3.0-L twin-turbo inline six for the 740i, and a 258-hp (192-kW) 2.0-L twin-turbo inline four and 83 kW electric motor plug-in hybrid-electric combination in the 740e. The hybrid's total system output is 243 kW. All three cars use eight-speed automatic transmission.

The V8 is a hot-vee design, nesting a pair of Honeywell twin scroll turbos in the valley of its vee. Compression for this iteration of the engine climbs a half-point to 10.5:1, with cooling optimized with separate flow to the heads and cylinder liners determined by a map-controlled water pump. System flow can be restricted to 10% of normal for faster warmup on cold starts.

BMW is debuting a new inline-six for 2016 featuring all-aluminum construction, variable valve timing, and direct gasoline fuel injection for a good combination of smoothness and power.

The plug-in hybrid 740e has a lithium-ion battery pack that can propel the car with no fuel consumption at speeds as high as 75 mph (120 km/h) or for distances as far as 23 mi (37 km). Charging is via standard household current, public charging station or BMW’s i Wallbox. BMW claims maximum efficiency of 112 mpg for the plug-in hybrid

Global markets will also enjoy the 730d, a 265-hp (198-kW) 3.0-L, 52-mpg fuel-sipping 3.0-L inline six-cylinder diesel.

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