The fourth generation of Infiniti M was introduced for the 2011 model year. This latest generation was known as the Y51, and featured a range of variants such as the M25, M37, and M56. These cars were offered in a four door sedan body style, and were powered by a range of V6 engines ranging from 2.5L to 5.6L in displacement, all of which were paired to a 7 speed automatic transmission. As well as rear wheel drive, the Y51 Infinti M was also available in all wheel drive. In 2013, Infiniti changed their naming system, so the M became the Infinti Q70.