The BMW 640i Convertible is a luxury convertible car produced by the German automaker BMW. It is part of the BMW 6 Series line of vehicles, and was first introduced in 2012. It is powered by a 3.0-liter TwinPower turbocharged 6-cylinder engine and an 8-speed Sport Automatic transmission. It features an xDrive all-wheel drive system and has a top speed of 155 mph. The 640i Convertible is an elegant vehicle, with a luxurious interior, powerful engine and a number of features and options.