Mercedes-Benz 300 SL
The Mercedes-Benz 300 SL is a two-seat sports car that was produced by Mercedes-Benz from 1954 to 1957 as a gullwinged coupé and from 1957 to 1963 as a roadster. The 300 SL traces its origins to the company's 1952 racing car, the W194, and was equipped with a mechanical direct fuel-injection system that increased the power output of its three-liter overhead camshaft straight-six engine.
The 300 SL was capable of reaching 260 km/h, earning it a reputation as a sports car racing champion and making it the fastest production car of its time. The car's iconic gullwing doors and innovative lightweight tubular-frame construction were groundbreaking.
The designation "SL" is an abbreviation of the German term super-leicht, meaning "super-light", a reference to the car's racing-bred lightweight construction. The 300 SL was introduced to the American market at the suggestion of Max Hoffman, Mercedes-Benz's United States importer at the time, who recognized the potential demand for a high-performance sports car among American buyers. The Mercedes-Benz 300 SL remains a highly sought-after classic car and is celebrated for its performance, design, and technological advancements.
Development
Origin in the W194 racing car
The 300 SL traces its origin to an endurance racer, the Mercedes-Benz W194, developed by Daimler-Benz in 1951. It used the 3-liter inline-6 M186 engine, shared by the company flagship 300 "Adenauer" saloon and the two-seat 300 S grand tourer.Although W194's engine produced less power than competing cars by Ferrari and Jaguar, its low weight and low aerodynamic drag made the W194 fast enough to be competitive in endurance races.
Mercedes-Benz developed a new version for the 1953 racing season by replacing the M186's carburetors with mechanical direct fuel-injection, and shifting to 16-inch wheels; the gearbox was installed on its rear axle. Its body was made of Elektron, a magnesium alloy, which reduced its weight by. Mercedes-Benz decided not to race this alloy car, choosing instead to begin participating in Formula One in 1954. Later versions revised the body to lower air resistance, and did not continue the transmission arrangement.
Origin of the 300 SL
The idea of Mercedes producing a toned-down Grand Prix car targeted to affluent performance enthusiasts in the booming post-war American market was suggested by the company's U.S. importer, Max Hoffman, at a 1953 directors' meeting in Stuttgart. Mercedes' new general director, Fritz Konecke, agreed to Hoffman's order for 1,000 cars to guarantee the success of the production run; the 300 SL was introduced at the February 1954 New York International Auto Show instead of the Frankfurt or Geneva shows, where company models usually debuted. In addition, the production of a smaller roadster, the Mercedes-Benz 190 SL, was announced after Hoffman placed an initial order for 1,000 to support their production. Mercedes received a positive visitor response to both cars in New York, and production began at the Sindelfingen plant in August of that year.Cost
The price for the 300 SL coupé in Germany was DM 29,000, and $6,820 in the US. The roadster was DM 32,500 in Germany, and $10,950 in the US – 10 percent more expensive than the coupé in Europe, and over 70 percent more in the US.| Option | Price |
| Color | 65 |
| Bumper guards | 40 |
| Windscreen washers | 18 |
| Becker radio | 264 |
| Leather upholstery | 165 |
| Fitted luggage | 85 |
| Crated shipment from factory | 80 |
| Competition springs | 88 |
| Competition front shock absorbers | 41 |
| Competition rear shock absorbers | 85 |
| Competition camshaft | 73 |
| Rudge wheels | 350 |
| Optional ring and pinion gears, per set | 80 |
| Hardtop for roadster | 178 |
SL abbreviation
Mercedes-Benz did not announce what the abbreviation "SL" meant when the car was introduced; magazines and company officials have called it "Sport Leicht" and "Super Leicht". It was called "Sport Leicht" on the company website until 2017, when "SL" was changed to "Super Leicht" after a chance finding in the corporate archives.300 SLS
A special 300 SLS version of the 300 SL roadster was created for the Mercedes-Benz US racing team to compete on the Sports Car Club of America national circuit in 1957. After the 300 SL coupé dominated the D Production class en route to titles in 1955 and 1956, the rules were changed to make the class more competitive by enlarging the maximum engine size from 3 to 3.5 liters. Rather than radically modifying its engine size, Mercedes-Benz created two roadsters to campaign on the D Modified class SCAA circuit. They featured a solid cover over the passenger seat, a low-profile racing screen in place of a full-width and -height windscreen, a driver's seat roll bar, a custom cowl with engine air intake, and no front and rear bumpers. These and other modifications lowered vehicle weight from to. Engine output was increased, to. Team driver Paul O'Shea again won the title for the company.Overview
The 300 SL has a steel tubular frame chassis, with a steel body combined with an aluminum bonnet, doors, dashboard, and boot lid to further reduce weight. An additional could be eliminated with an expensive all-aluminum body, but only 29 were made. Depending on the rear axle ratio, fuel consumption was 17 liters per 100 km.Interior
Three checkered-pattern seat fabrics were standard: grey and green, grey and blue, and cream and red. Most customers opted for leather upholstery, which became standard on the roadster. With upward-opening doors, the coupé has an unusually-high sill; entering and exiting the car is problematic. The steering wheel pivots on its hub 90 degrees away from the dashboard to facilitate entry.Mercedes-Benz 300 SL. Test in Auto, Motor und Sport, Motorbuch Verlag, Stuttgart, Heft 21/1955, Reprint in Motor Klassik, Spezial Nr. 3. Storage space for luggage is behind the seats in the coupé; the boot only holds a spare wheel and fuel tank. The roadster was available with two custom-fitted leather suitcases for the larger boot. The coupé's windows are fixed and roll down in the roadster.Exterior
The body consists mainly of sheet steel, with the bonnet, boot lid, dashboard, sill, and door skins made of aluminum. Silver-grey was the standard color; all others were options.The objective of the overall design was to make the vehicle as streamlined as possible. The width of the tubular frame along the cockpit allowed the cabin roofline to be inset considerably on both sides, dramatically reducing the front area. The structure was also quite high between the wheels, prohibiting the attachment of standard doors. The only option – already used on the W194 race car – which would allow passengers over its high, deep sill was a gullwing door.
The car’s distinctive eyebrows are a functional feature in the front, both physically and aerodynamically deflecting road water from the windscreen, and stylistic in the rear, added for visual symmetry.
Engine
The Mercedes-Benz M198 engine is a water-cooled overhead cam straight six. Like the racing Mercedes-Benz M194, the 300 SL borrowed the basic two-valves-per-cylinder M186 engine from the regular four-door 300 luxury touring car introduced in 1951.It featured the M186's aluminum head: a 30-degree diagonal base, allowing larger intake and exhaust valves than a standard horizontal joint with the engine block. To improve performance, the M198 replaced the W194's triple two-barrel Solex carburetors with a Bosch mechanical direct fuel-injection system. This raised output on the 300 SL from SAE gross to SAE gross at 6,100 rpm. Compression was set at 8.55:1.
| Maximum power | SAE gross at 6,100 rpm / @ 5,800 rpm DIN/ |
| Maximum torque | SAE gross at 4,800 rpm / @ 4,600 rpm; DIN |
File:Mercedes 300 SL Engine EMS.jpg|thumb|alt=See caption|The M198 OHC line-6 engine, with its sand-cast aluminum intake manifold
Another performance feature was dry sump lubrication, which ensured proper oil distribution in high-speed cornering and reduced engine height by eliminating a traditional oil pan. A more-powerful version of the M198, with a radical sports camshaft and 9.5:1 compression ratio, could be ordered free of additional charge for the coupé. The roadster had this engine only in its 1957 debut year. For the M198 engine to be installed in a low-profile car, it was tilted 50 degrees toward the driver's side. The result was aerodynamic efficiency and an enormous, sand-cast aluminum intake manifold as wide as the engine.
The engine was coupled by a single-disc dry clutch to a four-speed transmission with gear ratios of 3.34:1, 1.97:1, 1.39:1, and 1:1, and a reverse ratio of 2.73:1. The stock rear-axle ratio at the beginning of production was 1:3.42; at the 41st vehicle, it was changed to 1:3.64 for better acceleration. It allows a top speed of and acceleration from 0 to 100 km/h in 9.3 seconds. Faster acceleration was provided with ratios of 1:3.89 and 1:4.11. The lowest final-gear ratio, 1:3.25, delivered a top speed of up to and made the 300 SL the fastest production car of its time. City drivers found the tall first gear challenging. Clutch-pedal operation was initially cumbersome, remedied by an improved clutch-arm helper spring.
Unlike present-day electronic fuel-injection systems, the 300 SL's mechanical fuel pump would continue cycling so long as the engine turned over, maintaining the mechanical direct fuel-injection system's pressure, which would continue to inject gasoline into the cylinders during the interval between ignition shut-off and the engine's coming to a stop. This extra fuel washed away the oil film critical to an engine during start-up, and led to oil dilution, excessive ring wear, and scouring of the cylinder walls. Exacerbating the problem was the engine's dry-sump lubrication system, with its large oil cooler and enormous oil capacity, which virtually guaranteed that the oil would not get hot enough to flow properly on the short trips frequently taken by most car owners. Owners might block off airflow through the oil cooler and stick rigidly to the appropriately low recommended oil-change interval. An auxiliary fuel pump provided additional fuel for extended high-speed operation, but overuse could also lead to oil dilution. From March 1963 to the end of production later that year, a light alloy engine block was installed in 209 vehicles.