Longitudinal engine

In automotive engineering, a longitudinal engine, also sometimes known as a north-south engine, is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back. Most rear wheel drive vehicles use this engine orientation, while most front wheel drive vehicles use a side-to-side transverse arrangement. An exception is most Audi vehicles (those not using Volkswagen-based platforms) which continue to use the longitudinal layout even with larger displacement engines.

A common example of a longitudinal engine is the Boxer engine. This is a design where the cylinders are horizontally opposed, or facing each other. Common cars that share this design are: Alfa Romeo Alfasud (Flat-4), Alfa Romeo 145/146 (Flat-4), the Subaru Impreza (Flat-4) and the Porsche Boxster (Flat-6).