Audi has a Wankel for a range extender. 148.7 mpg (imperial) Audi A1 -click Below: the Wankel is so small it fits under the trunk floor: Audi A1 - report -click Audi has confirmed the A1 e-tron will be made using the Wankel range extender. A1 to be made -click GM did heavy Wankel...