This content is not included in your SAE MOBILUS subscription, or you are not logged in


  • Magazine Article
  • 20AUTP04_04
Published April 01, 2020 by SAE International in United States
  • English

Highlighting the many benefits of a century-old vehicle layout whose golden era is with today's performance cars.

What do a 1901 Curved-Dash Oldsmobile, a 1936 Auto Union Grand Prix car and the 2020 Acura NSX Hybrid and the new 2020 Chevrolet Corvette have in common? Their engines are located between the front and rear axles, behind the driver. The so-called ‘mid-engine’ drivetrain layout has found favor in passenger cars, mostly at low volume, since the beginning of the automotive age. It's been popular in various transit and school buses and fire apparatus as well.

Leading-edge racecar engineers, such as those at Auto Union and Mercedes-Benz in the 1930s, chose mid-engine over alternative powertrain layouts to minimize the vehicle's polar moment of inertia (or rotational inertia)-a physical object's resistance to rotation about any axis. In cars, a larger polar moment of inertia is typically created by a large distance between the vehicle's major masses. In such layouts, higher forces are required to stop and start any turning maneuver. The vehicle is less agile as a result.