All three versions W110, W111, and W112, in both two- and four-door bodies, were built on an identical chassis.
The updated and larger W108/W109 model lines were introduced in 1965.
During this period, the designation S (for "Sedan") was used for standard carburated short-wheelbase models; an E (for "Einspritzung", German for fuel-injection) was added to the 250SE, 280SE and 300SE.
Long-wheelbase models gained an L (for "Lang", German for "long"), reflecting an extra 10 centimeters added in the rear passenger compartment.
Since the advent of the W108 series, the Mercedes-Benz S-Class has always included two wheelbase lengths, although not all wheelbases are sold in every country.
The more powerful 300SE and 300SEL models were classified as the W109 chassis, with front and rear air suspension (rather than the coil spring based W108 rear suspension), and available burl walnut interior trim, automatic transmission, and power windows. only) and 6.3-litre V8 engines (in the SEL model only).
In automotive terms, Sonderklasse refers to "a specially outfitted car." Although used colloquially for decades, following its official application in 1972, six generations of officially named S-Klasse sedans have been produced.
Previous two-door coupe models of the S-Class were known as SEC and later S-Coupe.The W111 was a chassis code given to its top-range vehicles, including four-door sedans, produced from 1959 to 1968, and two-door coupes and cabriolets from 1961 to 1971.The W111, was initially attributed only to six-cylinder cars with 2.2-litre engines.The squarish W108 line included the straight-six M129 engine powered 250S, 250SE, 280S 280SE and 280SEL.In 1968 the 300 SEL 6.3 borrowed the 6-litre V8 from the W100 600 Pullman to offer a truly high-performance luxury sedan.In 1968, the W108 line dropped the 250SE in favor of the larger-engined 280S and 280SEL; the 250S remained as an entry model until 1969; the 300SE/SEL yielded their 3.0 litre inline-6 for the intermediate SL type (W113) 2.8 litre engine, and were later offered with a 3.5-litre V8 engine (in both the SE and SEL form, not in the U. The W108/109 lines, which eventually supplanted the W111 lines, were never available with four-cylinder engines.