The fuel economy of the Dodge Challenger 2015 depends on the engine size. The 3.6L V6 engine has an EPA-estimated fuel economy of 19 mpg city/30 mpg highway, the 5.7L V8 engine has an EPA-estimated fuel economy of 15 mpg city/25 mpg highway, and the 6.4L V8 engine has an EPA-estimated fuel economy of 14 mpg city/23 mpg highway.