The Mercedes-Benz S500 was a variant of the W221 S-Class that was introduced for 2006 in Europe. The S 500, which was sold as the S550 in North America, Canada and Japan, was built on the standard and long wheel base W221 platform and initially powered by Mercedes' M273 E55 engine. The M273 E55 was a 5.5L naturally aspirated V8 engine that generated 383hp. This engine was replaced in 2011 for the M278 engine, which was a 4.7L twin-turbo V8 engine that produced 429hp. The W221 S500 was built until 2013, although the model series would continue in the next generation W222 Mercedes-Benz S-Class.as the W222 Mercedes-Benz S500