Sport Package ($4,200 - includes 20-inch wheels with performance tires, leather sport steering wheel, multicontour seats, Shadowline exterior trim); Integral Active Steering ($1,750); Cold Weather Package ($950 - includes heated steering wheel, heated front and rear seats); iPod and USB Adapter ($400).
Twin-turbocharged, direct-injected, V-8
4,395cc (268 cu-in)
Double overhead camshaft
Compression ration (x:1)
Horsepower (hp @ rpm)
400 @ 5,500
Torque (lb-ft @ rpm)
450 @ 1,750
Transmission and axle ratios (x:1)
I = 4.70, II = 3.13, III = 2.10, IV = 1.67, V = 1.29, VI = 1.00, VII = 0.84, VIII = 0.67, R = 3.30, FINAL = 3.08
No matter how you launch it, the 550i GT is quick; however, we found the sweet spot in Sport Plus with DSC off and virtually no wheelspin. It took three attempts to "beat" Sport Plus with DSC on, however, so the sysem is well-calibrated.
Medium-firm pedal with little idle stroke and virtually no fade until the fifth stop. How does BMW do this with single-piston calipers and a 4,800-pound vehicle?
Skid pad: With DSC off, the GT tiptoes in understeer. Decent grip, and when Sport Plus mode is selected, the steering feels (more or less) linear and "normal." With DSC on and "Normal" mode selected, steering input (and effort) are decreased. DSC first applies brakes, then closes throttle to quell understeer. Slalom: In Normal mode with DSC on, the yaw response is incongruous with the minimal steering input. That said, the DSC is perhaps one of the best I've tested in that it makes the GT go EXACTLY where the steering tells it to go without the usual overcorrections or stumbling of other systems. With DSC off, the GT doesn't feel as massive as it truly is. Balance is remarkably neutral with slight understeer on the limit.