Car with engine mounted on movable floor portion

A car is provided with a support frame defining part of a lower floor of the car, with a passenger compartment projecting upwards from the lower floor, with a driving engine to move the car, and with an aerodynamic bottom, which is at least partly fixed to the support frame, defines part of the lower floor and has a fixed portion locked on the support frame and a movable portion locked on the driving engine and movable relative to the fixed portion.