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The gull wing car was not only practical - but it was esthetically beautiful.
Note that the coupes did not have enclosed headlights.

Over 160 MPH from a street car in 1955 - just incredible!
1954-1963 Mercedes 300 SL - Technology Personified, Performance Beyond Question

By Society Staff – reprint with permission only

The German "Hot Rod" of the 50s

OK, Mercedes has a reputation today for some killer high performance sports cars and sports sedans, and some of you may know about the famous pre-WW II Formula 1 race cars, but how many of you know that MB built some of the most dominating sports racers of the mid-50s - and a road car that might have been the absolutely fastest production car of the period, putting the likes of Ferrari and Jaguar to shame? This car was the Mercedes Benz 300 SL.

It's NOT the 300 SLR
Before we go further, it should be said that there were two distinct 300SLs produced, the 300 SL, which was produced from 1954 - 1963 and the 300SLR which actually had no relationship to the 300SL. The SLR was based not on the 300SL (W198) Gullwing road car, nor the earlier 1952 (W194) race car, although it bears a strong resemblance to both.

The 300SLR was based on the 1954–1955 Formula 1 Mercedes-Benz W196 race car. The 300SLR designation came from the  Mercedes marketing people, who considered 'W196S' an uninspiring name. It is thought that "300SLR" is in reference to the car's lightweight construction: "Sport Leicht Rennen". In this article we shall exclude the 300SLR - though its accomplishments may even be more stellar.

The "Regular" 300SL
The Mercedes-Benz 300SL featured here, was developed by Mercedes as the beginning of what would become the S-Class grand touring cars. It was intended by Mercedes to be the fastest production car of its day - and it was. Internally numbered as model "W198", it was first introduced in 1954 as a two-seat sports car with distinctive gull-wing doors. As it's popularity increased,  the coupe was dropped (1954-1957) and it was then offered as an open roadster (1957-1963).

The original 1952 300SL was a sports race car (not the later 300SLR mentioned above) , and its success inspired Max Hoffman, the Daimler-Benz official importer in the US at that time, to push the Factory to develop a toned-down version of the race car that would be tailored to affluent performance enthusiasts in the booming post-war American market. Max convinced Daimler-Benz AG management in Stuttgart that a street version of the 1952 300SL would be a commercial success.

Mercedes quickly responded and introduced what would become the street 300SL at the 1954 New York Auto Show - rather than the Frankfurt or Geneva shows at which other Mercedes models made their debuts. This was a stunning concession to the  Factory's understanding of the importance of the US market. When introduced, the "300" referred to its 3 Liter engine displacement, and "SL" stood for "Sport Leicht" (Sport Light).

The 300SL was and is best known for its distinctive gull wing doors, the first-ever consumer-available fuel-injection, and world's fastest top speed of its day. In a tribute to Max Hoffman's prescience, more than 80% of the vehicle's total production of approximately 1400 units were sold in the US.

This 300SL was significant because it was the first Mercedes-Benz which sold in considerable numbers outside its home market. Of course it confirmed the validity of Hoffman's suggestion. There is no question that the 300SL changed the company's image in America from a manufacturer of solid, but staid, automobiles to that of a producer of super-competent sports cars.

The street 300SL was directly derived from the 1952 300SL race car. As such, it was built around a strikingly similar tubular space frame chassis to save weight. In the race car, this frame was developed to offset its relatively underpowered carbureted six cylinder engine. In the street car, this was seen as an opportunity to derive stupendous performance better than or equal to V8 and V12 equipped sports/race cars of the day.

The 300SL was designed by Daimler-Benz's chief developing engineer, Rudolf Uhlenhaut. Its unique frame architecture resulted in the model's distinctive "gull-wing" doors, since part of the chassis needed to pass through what would be where the lower half of a standard door would be. Even with those gull wing doors, the 300SL had a very high sill, making entry and exit from the car's cockpit an issue. A tilt-away steering column was added to improve driver access.

Surprisingly, the street car's body was  mostly steel, except for the aluminum hood, doors and trunk lid. But it could be ordered with an all-aluminum outer skin at huge cost, but it did save about 175 pounds.

The Engine - power-packed 6-Cylinder
The 300SL's I-6 engine was  based on the 1952 W194 300SL race car, which utilized  a much less powerful carbureted version. The 300SL's version utilized direct fuel injection - incredible technology for its time. It stunned the automotive world. Some say it encouraged Bendix and Rochester to develop their units, with Rochester's Corvette FI becoming even more well know, due to the many, many FI equipped Corvettes manufactured. 

The six was canted at a forty-five-degree angle to the left to allow for a lower hood line, and was for the most part, the same 3.0L straight-6 as was used in the regular four-door 300 series cars. However, it was fitted with a Bosch mechanical direct injection system and a much more aggressive camshaft, which resulted in almost double the power of the original 115 hp carbureted version. (212 hp @ 5800 rpm).

It certainly was not the first fuel-injected gasoline engine. Mercedes engineers had developed the principle in WW II for their DB 601 fighter aircraft engine and had used fuel injection in the tiny 2-stroke "Gutbrod" they had designed after WWII, but it was the first to inject fuel directly into the cylinders. This innovation, light weight and excellent aerodynamics, allowed for a top speed of up to 161 mph, making the 300SL the fastest production car of its time.

But like other fuel injected cars of the period, the engine required a lot of tuning and maintenance. Unlike today's computer controlled fuel injection systems, the 300SL's mechanical system would continue to inject fuel into the engine when turned off and until the engine actually quit, and this fuel washed the oil from the cylinder walls and ended up diluting the engine's oil, especially on short trips when the engine temp did not allow for the gas to evaporate.

The engineers had also built a very large oil cooler and increased the capacity of the crankcase oil  to 10 liters, both carried over from the race engine. This pretty much guaranteed that the oil would not reach a high enough temperature.

Another issue was that the early versions had a very "heavy" clutch pedal, though this was improved when the later roadsters were delivered. In the last year of production, an aluminum crankcase was added to decrease weight (last 209 vehicles).

It should be noted that aerodynamics played a huge role in the car's top speed, with Mercedes-Benz engineers even placing horizontal "eyebrows" over the wheel openings to reduce drag. And unlike many cars of the period, the steering was relatively precise and the four-wheel independent suspension allowed for a reasonably comfortable ride and markedly better overall handling.

But like the "Unsafe at any speed" Corvair, it used a swing axle at the rear, not full IRS, which could turn treacherous at high speeds or on imperfect roads due to extreme changes in camber.  As a take off on the race car, it had a huge fuel tank. The fuel tank's capacity could cause significant differences in handling depending on how much fuel was on board.

Regardless of its foibles and idiosyncrasies, the 300SL was a dramatic and advanced car for its time. It is a testament that it was in production for ten years at a time when advances happened annually - and yet it was still state of the art when finally ceased production.

Significantly, not only did the car influence many later Mercedes sport models, but it impacted just about every other sports car built at the time, including the Jaguar XK-E and the Sting Ray Corvette.

The roadster was equally gorgeous

The roadster could be had with a removable top - combining the comfort of the gull wing with the practicality of the later convertible.

The 300SL race car which inspired the 300SL road car

A view of the race caer from the rear.
Mercedes worked to make the road car look quite similar.

The 300Sl's space frame.

The gull wing cars' interior was very purposeful, but also good looking.

The Roadster's interior remained true to the original, with more refinement.

The 300SL six cylinder - note the tuned intake to increase torque.

This view of the engine shows the direct injection pump.