Track Tested: 2009 BMW 750Li vs. 2009 Mercedes-Benz S550

These are the big guns from BMW and Mercedes-Benz. Well, not the biggest guns, but with prices near or above the $100,000 range, they're big enough. The BMW 750Li is all-new for 2009 and looking better than ever. Its 400-horsepower twin-turbo V8 makes it the closest thing to a "Motorsport" 7 Series we have ever seen. The Mercedes-Benz S550 is getting a face-lift next year, but the current model has held up well. And with a 382-horsepower V8 of its own, it doesn't give up much to the new BMW.

One look at the track numbers and you'll be amazed what these 2.25-ton sedans can do. From 13-second quarter-mile sprints to 110-foot stops from 60 mph, these two sedans are perfect examples of what can be accomplished when money is no object. Full details after the jump.

	BMW 750Li	Mercedes-Benz S550
0 - 30 (sec):	2.0	2.3
0 - 45 (sec):	3.6	3.8
0 - 60 (sec):	5.1	5.7
0 - 75 (sec):	7.5	8.2
1/4 Mile (sec @ mph):	13.4 @ 104.9	13.9 @ 101.0
0-60 with 1-ft Rollout (sec):	4.8	5.4
30 - 0 (ft):	27.0	27.0
60 - 0 (ft):	111	108
Braking Rating:	Excellent	Excellent
Slalom (mph):	63.4	63.4
Skid Pad Lateral acceleration (g):	0.84	0.87
Handling Rating:	Very Good	Very Good

Vehicle: 2009 BMW 750Li
Odometer: 1,968
Date: 04/07/09
Driver: Chris Walton
Price: $89,825

Specifications:
Drive Type:    rear wheel drive
Transmission Type:    6-speed automatic
Engine Type:    V8
Displacement (cc / cu-in):    4,395cc (268 cu-in)
Redline (rpm):    6,500
Horsepower (hp @ rpm):    400 @ 5,500
Torque (lb-ft @ rpm):    450 @ 1,800
Brake Type (front):    Ventilated disc
Brake Type (rear):    Ventilated disc
Steering System:    Speed-proportional power steering
Suspension Type (front):    Double wishbone
Suspension Type (rear):    Multilink
Tire Size (front):    245/45R19
Tire Size (rear):    275/40R19
Tire Brand:    Goodyear
Tire Model:    Excellence
Tire Type:    All-season
Wheel Size:    19-by-8.5 inches front -- 19-by-9.5 inches rear
Wheel Material (front/rear):    Alloy
As tested Curb Weight (lb):    4,607

Acceleration Comments:    I tried so many combinations (Sport, Sport w/Dynamic Traction, Sport w/DSC off, etc.) that I can't say with certainty which one was quickest. I think Sport +, DSC off, manual shift (but still auto upshift) was the winner. Zero wheelspin was definitely the best and geez is this thing a rocket. Shift were fast, bordering on harsh, and the power felt limitless.

Braking Comments:  At a loss to explain diverse stopping distances (perhaps a hop in the pavement), but the brakes always felt strong and fade-free. Huge initial bite, then a superfast ABS cycle with zero drama. More dive than expected, even in the Sport chassis setting.

Handling Comments: Benign understeer at the limit with DSC off that was diminished greatly with DSC on -- which proved to be the quicker way around the skid pad. Steering gets much heavier as speed increases. (Slalom) Amazingly "buttery" steering feel, good turn-in, but there's no doubt this is a long-wheelbase car. Good balance, but even in sport chassis mode there's more roll than I expected, plus understeer at the limit. Also noticed that the seatbelts snug up when you start tossing this car around.

Vehicle: 2009 Mercedes-Benz S550
Odometer: 2,833
Date: 04/07/09
Driver: Chris Walton
Price: $111,550

Specifications:
Drive Type:    Rear-wheel drive
Transmission Type:    7-speed automatic
Engine Type:    V8
Displacement (cc / cu-in):    5,461cc (333 cu-in)
Redline (rpm):    6,500
Horsepower (hp @ rpm):    382 @ 6,000
Torque (lb-ft @ rpm):    391 @ 2,800
Brake Type (front):    Ventilated disc
Brake Type (rear):    Ventilated disc
Steering System:    Speed-proportional power steering
Suspension Type (front):    Multilink
Suspension Type (rear):    Multilink
Tire Size (front):    255/40R19
Tire Size (rear):    275/40R19
Tire Brand:    Continental
Tire Model:    SportContact2
Tire Type:    Performance
Wheel Size:    19-by-8.5 inches front -- 19-by-9.5 inches rear
Wheel Material (front/rear):    Alloy
As tested Curb Weight (lb):    4,630

Acceleration Comments:    Responds well to brake torque, but not wheelspin. Smooth linear power delivery with aggressive exhaust note. Shifts are buttery smooth, but not very quick.

Braking Comments:   Crazy powerful brakes that don't fade a bit. Very little dive, but pedal is always a little soft. Belt cinches tightly when ABS engages.

Handling Comments:   (Skid pad) In both skid pad and slalom tests, I couldn't detect any difference between ESP on and ESP off. Also the Active Body Control (ABC) is very strange, but works amazing well -- keeping all four tires firmly planted. Delivers zero body roll, which makes it easy to keep on line with only minor corrections. (Slalom) Through the slalom, ABC leans the car into the turn like a skier! Very strange. In the end, ABC and ESP made every run easily repeatable. Same speed with ESP on or off.