Mercedes Classic: 260D vs 300SD Turbodiesel vs C111/III vs E300 BlueTEC

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In this months issue of Mercedes Classic there was a great story about four important Mercedes-Benz diesel cars. These are the 1935-1937 260D, 1977 300SD Turbodiesel, 1978 C111 / III and the current E300 BlueTEC. The article mentions each car in detail and how they shaped the history of Mercedes diesels. 56% of Mercedes' passenger cars sold in Europe are now diesel-powered while global diesel passenger car sales are at 35%.




The 1935 260D was the first mass-produced diesel sedan in the world. Mercedes took a high risk producing this car as there was no market for it in pre-war Germany. Even trucks used gasoline engines in those days. Most clients were taxi companies that valued reliability and fuel economy over acceleration and refinement. The 260D produced 45-horsepower from its 2.6-l 4-cylinder engine and brought the car up to a top speed of 94 km/h while using 9 / 11 liters of diesel per 100 km: making it very efficient for its time. The 260D was based on the '200 chassis Mercedes' sold at the time offering great comfort and a lot of interior space. Taxi drivers soon reported positive characteristics about the car and engine praising the gas mileage and reliability. The car used in the photoshoot is from the Mercedes-Benz Museum.

From then on until the mid 1970s Mercedes' diesels improved in terms of refinement and fuel economy, but they were still slow, noisy and smelled bad. This changed in 1977.

In 1977 Mercedes introduced the 300SD Turbodiesel. This car was significant in two ways. One, it was the first diesel S-Class and two, it was the first turbocharged 5-cylinder diesel car in the world. The 3005cc engine produced 115-horsepower and accelerated the car from 0-100 km/h in 17 seconds all the way up until 165 km/h. Fuel economy was rated at 14 liters per 100 km. In modern day driving the 300SD Turbodiesel does surprisingly well. It is very comfortable and the engine noises are somewhat kept out of the cabin. The 300SD Turbodiesel was only sold in North America in order to help Mercedes' improve its CAFE standing. The W116 300SD Turbodiesel here is privately owned.

A year later, Mercedes showcased the potential of the diesel engine with the C111 / III. This specially designed car had a coefficient of drag rating of 0.183. It broke a number of world speed records and set new records for diesel-powered cars. Even more important was that the C111 / III used the same engine as the 300SD Turbodiesel with a few minor modifications such as different camshafts and different pressure ratings on the Garrett turbocharger (raised to 2.1 BAR). The result were 230-horsepower and speed in excess of 300 km/h. At Nardo in 1978, the C111 / III was able to reach a top speed of 327 km/h at an average fuel consumption of 16 liters per 100 km - an amazing feat given those speeds.

After this Mercedes' began offering a number of 'Turbodiesel' models in every class. By the early 1990s turbodiesel-technology made the cars agile and quiet enough to please even the most critical of customers.

Then in 1997 Mercedes' brought out the W202 C220 CDI with common-rail technology. This was another major leap forward in diesel technology and now we're at the E300 BlueTEC, the cleanest and quietest diesel in the world.



The Scans