Sales of the new Volvo C70 hardtop convertible have been so brisk that company has already upped its production from 16,000 annual units to 20,000. It will likely become even more popular now that Volvo has introduced its first diesel engine in the Swedish convertible, a 2.4L turbodiesel initially developed for the S60, S70, XC70 and XC90 but downsized and detuned for the C70. Known as the D5, this five-cylinder turbodiesel develops 180 horsepower and 258 ft-lbs. of torque. It will initially be mated with a five-speed automatic transmission.