Less mass is always better.
To motivate what mass there is, BMW offers three twin-turbo engines: an inline six in the 740i (326 horsepower); a 4.4-liter V8 in the 750i and 750Li (407 hp); and a diesel in the 730d (245 hp and a tractor-like 540 pound-feet of torque at a mere 1,750 rpm). The U.S.-bound models will initially get only the 4.4-liter gas engine. BMW execs won't commit to bringing the oil-burner stateside.
And yet, lighter is not light. The standard-wheelbase 750i weighs a bridge-bending 4,564 pounds. The long wheelbase 750Li is 4,640 pounds. To counter the sway, the lurch and slide of a heavy sedan driven in anger, BMW has completely re-engineered the 7 Series' greasy bits.
The front suspension is now a double-arm design, while the rear is a so-called Integral-V design. Meanwhile, there's a phalanx of so-called Dynamic systems -- active dampers, stability control, traction and anti-lock control, smart brakes -- as well as BMW's uncanny Dynamic Drive body-control system. This last system, one of the car's few options, comprises an electromechanical anti-roll bar in the back that nulls body roll as the car corners.
So it is that BMW engineering geeks have subverted Newton's laws. But there's still the problem of changing direction. A big, heavy car, relying on those two tires up front, can only exert so much steering force. The heavier the car, the less willingly it will go left or right, right?
The zolution, as German engineers say, is the optional Integral Active Steering. Rear steering has been tried by many companies many times, and has typically been abandoned because of weight, cost and complication. None of that is a factor in the flagship BMW.
The effect of all these components -- harmonized by a high-speed data system BMW calls FlexRay -- is pretty amazing. Come to a corner in the 750Li and get on the brakes hard. The dampers instantly react to compensate for the nose-diving weight transfer. Turn the wheel, and the four-wheel steering bites. The car tracks like a phonograph needle. Mid-corner, where other big cars would be fighting desperately against their own body roll, the Bimmer's body stays flat. The six-speed transmission holds its gear so as not to upset the car's balance. Get back on the gas and unwind the wheel. Perfection.
