Every year we look forward to an updated BMW 6-series, and every year BMW tweaks a few things, but neglects the exterior design. We reviewed aearlier this year, and found the 2010 model to be much the same car. The new BMW 650i Convertible uses the same power train and, sadly, has the same ugly rear-end and nondescript profile.
The notable difference with the 2010 BMW 650i Convertible is the new iDrive system, a major improvement for the new model year. Replacing the old quadrant menu is a simple list menu, and the various cabin tech functions are made very accessible with the new console-mounted controller. The new interface is a welcome change in the 6-series, which lagged behind other models in this regard.
Rubber, meet road
Where the 650i Convertible doesn't lack is in handling, showing BMW's signature sporting abilities. A big expensive two-door like this, with a convertible top, will probably never be pushed very hard, acting more as a gentleman's sports car, but BMW isn't known for compromising performance. The 650i Convertible is long, but in even tight turns it keeps body roll minimal, and lets the back slip out just a little so that a competent driver can enjoy the feeling of controlling the car.
A button labeled Sport on the console changes steering and throttle response, and makes the six-speed automatic transmission maintain higher engine speeds. Those sharpened responses help the car power through the corners, giving almost-immediate power to the rear wheels when called for from a good push on the accelerator. The thick steering wheel offers a lot of grip as it points the car, and understeer is held in check as the car rotates.
Sending power to the rear wheels is the same 4.8-liter V-8 found in the previous model year. It's a pretty advanced engine by anyone's standards, using BMW's double VANOS system to control throttle with the valves. But by BMW standards, it is behind the times. The 2009 BMW 750Li, which we reviewed earlier this year, uses a 4.4-liter V-8 with twin-turbochargers. BMW already applied twin turbochargers to its six-cylinder engine. That the 650i Convertible's engine is naturally aspirated shows that it hasn't come in for a power-plant update yet.
The 4.8-liter V-8 puts out 367 horsepower and 361 pound-feet of torque, which sends the car to 62 mph in 5.6 seconds when equipped with the automatic transmission. By contrast, the smaller displacement turbocharged engine of the 750Li puts out 407 horsepower and 442 pound-feet of torque. Fuel economy on either car isn't very impressive, with the 650i Convertible getting an EPA-rated 15 mpg city and 23 mpg highway. During our time with it, a mixture of city, freeway, and mountain driving returned 18.3 mpg.
Much improved electronics
But similar to the 750Li, the 650i Convertible can be had with some innovative driver assistance technology. Our car came with lane departure warning, a system that buzzes the steering wheel if you cross a lane line. The warning only comes on under certain conditions, such as speeds over about 40 mph and if the turn signal is off. Other technologies available, but not included on our car, are adaptive cruise control and a night vision system.
Our 650i Convertible did come with a head-up display, a projection on the windshield in orange that by default displays the car's speed. When route guidance is active on the navigation system, the display shows information on upcoming turns. This last feature is particularly useful, as we never had to glance down at the car's LCD while following its directions.