Mercedes-Benz 300 SL

Mercedes-Benz 300 SL
300 SL Roadster beside the Coupe version
Overview
Manufacturer	Mercedes-Benz
Production	1954–1957 (Coupe) 1957–1963 (Roadster) 3,258 built[1] Coupe: 1,400 Roadster: 1,858
Assembly	West Germany: Stuttgart-Untertürkheim
Body and chassis
Class	Sports car / Grand tourer
Body style	2-door Coupe, Roadster
Layout	FR layout
Platform	Coupe W198 I, Roadster W198 II
Doors	Gull-wing (Coupe) Conventional (Roadster)
Related	Mercedes-Benz W121 BII (190 SL)
Powertrain
Engine	2,996 cc (182.8 cu in) M198 Straight six
Transmission	4-speed manual
Dimensions
Wheelbase	2,400 mm (94.5 in)
Length	4,520 mm (178.0 in)
Width	1,790 mm (70.5 in)
Height	1,300 mm (51.2 in)
Curb weight	Coupe 1,500 kilograms (3,300 pounds), Roadster 1,560 kilograms (3,440 pounds), from 1961 1,660 kilograms (3,660 pounds)
Chronology
Predecessor	Mercedes-Benz W194 (racing car)
Successor	by name: Mercedes-Benz W113 (230SL) spiritual: Mercedes-Benz SLS AMG

The Mercedes-Benz 300 SL (chassis code W 198) is a two-seat sports car that was produced by Mercedes-Benz as a gullwinged coupe (1954–1957) and roadster (1957–1963).^[2] It was based on the company's 1952 racer, the W194, with mechanical direct fuel-injection which boosted power almost 50% on its 3-liter overhead camshaft straight-6 engine.^[3] Capable of reaching a top speed of up to 263 km/h (163 mph), it was both a sports car racing champion^[4] and the fastest production car of its time.^[3]

Max Hoffman, Mercedes-Benz's authorized United States importer at the time, inspired the 300 SL and correctly perceived an American market for such a car. The company introduced the 300 SL in February 1954 at the International Motor Sports Show in New York City instead of Europe to get it into U.S. buyers' hands sooner.

SL is the short form for "super-light" in German,^[5] Mercedes' first use of the designation, referring to the car's racing-bred light tubular frame construction.

The 300 SL was voted the "sports car of the century" in 1999.^[6]

Development[]

Origin in the W194 racing car[]

The 300 SL (also called W198) traces its origin back to a racing sports car, the Mercedes-Benz W194. In 1951, Daimler-Benz decided to take part in races and build a sports car for this purpose. Mercedes' largest engine, the M186 shared between the 300 "Adenauer" saloon (W186) and luxurious 300 S two-seat tourer (W188), was developed.^[7]

Mercedes-Benz W194 racing car

In 1952, the W194 took part in the most important races of the year. The new SL competed in the Mille Miglia at the beginning of May and achieved second place. It won the top three places at the Bern Sports Car Prize 131.04 kilometres (81.42 mi). At the 24-hour race at Le Mans, the 300 SL won the top two places. First place went to Hermann Lang and Fritz Riess with an overall average 155.6 km/h (96.7 mph), they achieved a new record in Le Mans history. Second place went to Theo Helfrich and Helmut Niedermayr. A race at the Nürburgring ended with a four-fold success. At the Carrera Panamericana in Mexico, the 300 SL again won with Karl Kling and Hans Klenk – despite having a vulture flying through the windscreen.^[8]

W194 at the Carrera Panamericana in Mexico, 1952

These successes, especially those on the high-speed open road races, were somewhat surprising as the W194 engine was fitted only with carburetors, producing 175 hp (130 kW), which was not only less than the competing cars by Ferrari and Jaguar, but also less than the 300 SL road car developed from it introduced in 1954. Low weight and low aerodynamic drag made the W194 fast enough to be competitive in endurance races.

1953 intermediate model at Pebble Beach in 2012

Mercedes-Benz developed a new version for the 1953 racing season by adding fuel injection and 16-inch wheels. The gearbox was installed on the rear axle. Its body was made of Elektron, a magnesium alloy, to reduce the weight by 85 kilograms (187 pounds). Mercedes-Benz decided not to race this alloy car as they decided to participate in Formula One from 1954 onward.^[9] Later versions revised the body for lower air resistance and did not adopt the transmission arrangement.

Start of the 300 SL[]

New York Auto Show 1954

Mercedes-Benz 300 SL prototype

Mass production of the 300 SL was initially not planned. The idea of a toned-down Grand Prix car tailored to affluent performance enthusiasts in the booming post-war American market was suggested by Max Hoffman at a director's meeting in Stuttgart, in 1953.^[10][3] Mercedes' new General Director Fritz Konecke agreed when Hoffman put an order in for 1000 cars^[10] and the new 300 SL was introduced at the 1954 New York Auto Show rather than the Frankfurt or Geneva gatherings where company models made their usual debuts. Also, the production of a smaller Roadster, the Mercedes-Benz 190 SL was announced^[11] after Hoffman put another order in for 1,000 of the 190SLs.^[10]

The two sports cars premiered at the "International Motor Sports Show" in New York, which took place in February 1954. Mercedes-Benz experienced a very positive visitor response to the 300 SL and the 190 SL at the Motor Show. Serial production began in August 1954 at the Sindelfingen plant.

Cost[]

The price for the Coupe in Germany was DM 29,000 and $6,820 in the US.^[10] The Roadster was DM 32,500 in Germany and $10,950 in the US – a 10% jump in Europe but an over 60% increase in the US over the Coupe.^[12]

^[13]

Sport-Leicht or Super-Leicht[]

Mercedes-Benz did not announce what the abbreviation "SL" meant when the car was introduced and various magazines and company officials have gone back and forth between Sport Leicht and Super Leicht (light).^[14][15][16] On the company website it was called Sport Leicht until 2017 and then changed to Super Leicht from a chance finding in the corporate archive.^[17][18]

300 SLS[]

The championship-winning 300 SLS was a 300 SL Roadster modified to comply with Sports Car Club of America class racing standards

A special 300 SLS (Super Light Special) version of the 300 SL Roadster was created for the Mercedes-Benz U.S. racing team to compete in the Sports Car Club of America (SCCA) national circuit in 1957. After the 300 SL Coupe completely 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 3.0 to 3.5 liters. Rather than radically modify its engine size (on the cusp of releasing the company's new 300 SL Roadster to replace the Coupe), Mercedes-Benz instead created two specially modified Roadsters to campaign in the D Modified class SCAA circuit. These 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 a lack of front and rear bumpers. These and other modifications lowered vehicle weight from 1,420 kilograms (3,130 pounds) to 1,040 kilograms (2,290 pounds). Engine output was increased 20 hp (15 kW) to 235 hp (175 kW). Team driver Paul O'Shea once again brought home the title for the company.^[4]

Overview[]

High door threshold for Coupe

The 300 SL has a weight-saving tubular frame atop a steel chassis, with a steel body attached to the frame. To further reduce weight, its bonnet, doors, dashboard, and boot lid were aluminum. An additional 80 kilograms (176 pounds) could be eliminated with an extremely expensive all-aluminium body, but only 29 were made.^[10]

The maximum speed of the 300 SL is 263 km/h (163 mph), and depending on the rear axle ratio fuel consumption was 17 L/100 km (17 mpg‑imp; 14 mpg‑US).

Interior[]

Three checkered pattern seat fabrics were available as standard. The combinations of the primary colors were grey/green, grey/blue, and cream/red.^[19] Most customers opted for leather upholstery, which became standard on the Roadster.

Even with the upward-opening doors, the Coupe has an unusually high sill, making entry and exit from the car's cockpit problematic. To further facilitate entry, the steering wheel pivoted on its hub 90 degrees away from the dashboard.^[20]

Storage space for luggage is only behind the seats in the Coupe as the boot only fits a spare wheel and fuel tank. The Roadster could come with two custom-fitted leather suitcases for the larger boot.

The windows in the Coupe are fixed but 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 at an additional expense.^[21]

The objective of the overall design was to make the vehicle as streamlined as possible. The exceptional width of the tubular frame along the cockpit allowed the cabin roofline to be inset considerably on both sides, dramatically reducing the frontal area. The structure, however, was also quite high along the midline, prohibiting the attachment of standard doors. The only option – already used on the W194 race car – would allow passengers up and over an exceptionally high and deep sill was the now-iconic gull-wing doors. Rather than an aesthetic choice, they were a design necessity.

Eyebrows are a stylistic feature that also stretch the curvaceous body.^[22][23] The front pair deflect road water from hitting the windscreen and the rear had to be added for visual symmetry.^[24] These eyebrows give styling to an otherwise slab-sided body. Mercedes-Benz claimed they were aerodynamic additions and pushed airflow over the top of the car and kept the windows clean in bad weather.^[25]

Engine[]

The Mercedes-Benz M198 engine is a water cooled 3.0 L; 182.8 cu in (2,996 cc) overhead cam straight-six. Like the racing Mercedes-Benz M194, the 300 SL borrowed the basic 2 valve per cylinder M186 engine from the regular four-door 300 (W186 "Adenauer") luxury tourer introduced in 1951.^[3]

As such, it featured the M186's innovative aluminium head, which had a 30-degree diagonal base that allowed for 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.^[3] Derived from the DB 601 V12 used on the Messerschmitt Bf 109E fighter of World War II, it boosted power almost 25% over the Gran Prix cars, raising output from 175 hp (130 kW; 177 PS) SAE gross to 240 hp (179 kW; 243 PS) SAE gross at 6100 rpm (215 hp (160 kW; 218 PS) DIN at 5800 rpm), over double that of the original Type 300 saloon's 115 hp (86 kW; 117 PS) SAE gross.^[26] Compression was set at 8.55:1.^[10]

Another high-performance feature was race-bred dry sump lubrication, which ensured proper oil distribution at high-speed cornering and reduced engine height by eliminating a traditional oil pan.

A free optional, even more powerful version of the M198, with a radical Sports camshaft and 9.5:1 compression ratio,^[10] could be ordered for the Coupe. The Roadster had this engine only on its debut in 1957.

The M198 engine, with its distinctive massive sand-cast aluminum intake manifold

In order for the M198 to be installed in the low profile car, it was tilted 50 degrees toward the driver's side.^[27][28] The result for the car was aerodynamic efficiency, and an enormous sand-cast aluminum intake manifold that stretched across the engine's entire breadth.^[29]

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 of 2.73:1.^[26] The stock rear axle ratio at the beginning of the construction period was 1:3.42; From the 41st vehicle, it was changed to 1:3.64 to give better acceleration. It allows a top speed of 235 km/h (146 mph) and acceleration from 0 to 100 km/h (62 mph) in 9.3 seconds. Faster acceleration was provided with ratios of 1:3.89 and 1:4.11. The lowest final gear ratio, of 1:3.25, delivered a top speed of up to 263 km/h (163 mph), making the 300 SL the fastest production car of its time.^[3]

City drivers found the tall first gear a challenge.^[11] Clutch pedal operation was initially cumbersome, remedied by an improved clutch arm helper spring.

Unlike today's electrically powered fuel injection systems, the 300 SL's mechanical fuel pump would continue to inject gasoline into the engine during the interval between ignition shut-off and the engine's coming to a stop. This extra fuel both washed away the oil film critical to an engine during start-up and led to oil dilution, leading to excessive ring wear and scouring of the cylinder walls. Exacerbating the problem was the engine's racing-oriented dry-sump lubrication system, with its large oil cooler and enormous 15 l (4.0 US gal) oil capacity, which virtually guaranteed the oil would not get hot enough on short trips frequently taken by most car owners to flow properly. Owners might block off airflow through the oil cooler and stick rigidly to the appropriately low 1,600 km (1,000 mi) recommended oil change interval. An auxiliary fuel pump provided additional fuel for extended high-speed operation or cold starts, but overuse could also lead to dilution of the oil.^[30][31]

From March 1963 to the end of production later that year, a light alloy crankcase was installed in 209 vehicles.^[32]

Chassis[]

Tubular frame

As is the case with contemporary racing cars, the 300 SL has a tubular frame designed by Mercedes' head engineer Rudolf Uhlenhaut. A tubular frame ensured high stability with low vehicle mass. Thin straight chrome-molybdenum tubes were assembled as several triangles and the finished frame weighs 82 kilograms (181 pounds). The tubes make a deep side panel, so gullwing doors are needed to enter the car.^[33] The frame on the Coupe has two side rails with the top tube at the level of the driver's elbow.^[10] The center of gravity is almost exactly in the middle of the vehicle.

The chassis was a regular Mercedes-Benz W186 but with a sportier tuning. Unlike many cars of the 1950s, recirculating ball steering was relatively precise, and the four-wheel independent suspension allowed for a reasonably comfortable ride and markedly better overall handling. Front suspension was double wishbones, coil springs, stabilizing bar. However, the rear swing axle, jointed only at the differential, not at the wheels themselves, could be treacherous at high speeds or on bad roads due to extreme changes in camber. The Coupe has a high-pivot swing axle, radius arms, coil springs. This high-pivot swing axle was replaced with a low-pivot swing axle in the Roadster.^[10]

Wheels[]

The front wheels are hung on double, unequal length wishbones with coil springs and hydraulic telescopic shock absorbers and a torsion bar stabilizer was installed. The Coupe's rear axle was of a two-joint design with one joint at each side of the differential at its centre line.^[19]

The Roadster's wheels were larger than the Coupes'. The wheels were steel bowl/aluminum rim rivet compound wheels. A valuable option was the Rudge rims 5J × 15 inches. The tires were 6.50-15 inches on the Coupe and 6.70–15 on the Roadster.

Rudge rims and eyebrow

The 300SL had the same 1,470 square centimetres (227.9 sq in) area, self cooled, turbo drum brakes as on the 300S Mercedes.^[34] A brake booster was used to reduce the pedal force. The brake booster works by using the negative pressure in the intake manifold. Brake shoes were 90 millimetres (4 in) wide. The front drum brakes were two-wheel brake cylinders/wheel, and the rear drum brakes were one-wheel brake cylinder/wheel. The handbrake was a mechanical parking brake that acts on the rear wheels. The Roadster had the same drum brakes until March 1961 when Ø 290 millimetres (11.4 in) disc brakes were introduced front and rear.^[20]

Roadster[]

The Roadster was produced from 1957 until 1963

Mercedes-Benz 300 SL Roadster with hardtop

In mid-1956, Mercedes was evaluating what to do with the Coupe. Sales of the Coupe had started to fall off, and the board decided to show a convertible version at the Geneva show in March and convert the factory completely to the Roadster in May 1957 to meet the needs of the California market.^[10][34]

Built with conventional doors, the 300SL Roadster was first exhibited at the Geneva Salon in May 1957.^[10][34] The production of an open 300SL involved altering the cockpit area, where the space frame was redesigned to permit lower sills for improved access.^[10][34] At the same time the rear suspension was changed to incorporate low-pivot swing axles.^[10][34]

The Roadster at 1,420 kilograms (3,131 pounds) weighs 125 kilograms (276 pounds) more than that of the Coupe, but with 240 hp (179 kW) the Roadster has slightly more power. The tubular frame on the Roadster still supported the body, but was changed to create more space in the boot. The spare tire was placed under boot floor and combined with a smaller fuel tank gave room for specially made fitted luggage. The lower door-line closer to the ground gives a much more comfortable entry.^[35]

The rear axle was changed to a single joint arrangement with its pivot point located 87 mm below the differential centre line.^[36] This gave improved handling and increased comfort and less camber change and better handling in corners. Uhlenhaut wanted the new low pivot axle for the Coupe but was voted down by the board of directors, reminding him that 3000 manufactured axle units remained at the factory and costs were already getting very high for this car.^[10] A hardtop became an available option from September 1958.^[10]

Racing[]

At the beginning of the 1950s, Mercedes decided to return to international motorsport. Alfred Neubauer was entrusted with this function again.^[37] In 1951 Mercedes built 5 V8 W165 cars and engines to enter the Grand Prix.^[37] Unfortunately, Ferrari's V16 showed well at Silverstone, and Neubauer knew that the W165 could not win.^[37] Mercedes started planning a V12 W195.^[37] In October 1951 the FIA sporting commission changed the rules for 1954 and the W195s could not compete.^[37] In the meantime, Mercedes turned to develop the six-cylinder 300 SL for racing. Originally the doors extended onto the bottom of the side windows and access through the doors required a removable steering wheel.^[38]

1952[]

The 300 SL's first race was in the 1952 Mille Miglia.^[39] Mille Miglia was a 1,564 kilometres (972 mi) race with start and finish from Brescia to Rome and back between Kling's 300SL and Giovanni Bracco's new 3-liter V-12 Ferrari.^[40] Bracco won with a margin of only 4 minutes and 32 seconds over Karl Kling in second place.^[40] Driving a car with a less powerful engine than the others, Rudolf Caracciola placed fourth.^[40]

Two weeks after the Mille Miglia, the original four cars raced at Bern before the Grand Prix. Concerned that Le Mans officials would not accept the gullwing door arrangement at Le Mans, Daimler-Benz devised a continuation of the door down into the side of the body.^[40] Locking of the rear brakes was a continuing problem for the 300 SL and Caracciola's coupe hit head-on into a tree. Caracciola did not race again.^[37] Karl Kling, Hermann Lang, and Fritz Riess finished first, second, and third when the 4.1 liters Ferrari broke down at the start.^[40]

For the Le Mans, 24 hours race in June, three brand-new cars were constructed.^[40] The engines were detuned for the long race to 166 bhp, and the fuel tank filler rose above the rear window.^[40] The team brought an experimental spare car with a rooftop air brake which folded flat until activated by the driver. The sight of the brake unnerved the other drivers.^[40] The brake was effective, and at 100 mph, the brake could exert a deceleration of up to 0.2 g, but it also weakens the supporting pylons.^[40] The cars went through more tires than expected, and Kling/Klenk was forced out of the race by a generator failure.^[40] Lang and Riess won the Le Mans race with an average speed of 155.574 kilometres per hour (96.669 mph) and Theo Helfrich/Helmut Niedermayr placed second.^[40]

The Nürburgring race on August 2 was a contest of only 142 miles (229 km) over a difficult track. The competition moved to Jaguar and Alfa Romeo.^[40] Nürburgring required light and powerful cars, and aerodynamics was less important, so the tops of the coupes were chopped off to create a 300SL roadster with the rear deck and the passenger's side covered with an aluminum tonneau.^[40] All four cars raced at Nürburgring in unsupercharged form after trials did not show a benefit with a supercharged engine. The supercharged engine was tried but proved no faster than the standard 300 SL.^[40] The team concluded that the car’s relatively crude swing axle rear suspension was already at its limit in its ability to transmit the car's power to the road and the engine was less durable.^[38] Lang won the race with Kling and Riess coming 2nd and 3rd.^[40]

This was the official end of the company’s efforts with the 300 SL as it felt that it had done all it could with the six-cylinder racers, and it would concentrate on the Grand Prix. One last outing was not to be resisted.^[40]

With pressure from the Daimler-Benz representative in Mexico City, the company sent Mexico two 3½-ton trucks and 35 people to compete in the 3rd Carrera Panamericana.^[40] Two 300 SL coupes were updated with the exhausts through the right-hand sides and new window moldings along with two roadsters.^[40] As there was no 3-liter class, the cylinder displacement was increased to 3.1liters to give 177 bhp.^[40] Continental did not have the time or knowledge to make special tires for the event, so they sent 300 tires of different types.^[40] Lang struck a dog, and Kling hit a buzzard in the early stages, going 135 miles per hour (217 km/h).^[40] The 300 SLs did better later and finally overtook the lead Ferrari driven by Bracco. Kling/ Hans Klenk came first and Lang/Erwin Grupp was second.^[40] A 1-2-3 finish may have been the final result had American John Fitch not been disqualified for permitting a mechanic to touch his car on the second to last day.^[40]

At the Carrera Panamericana in Mexico, the 300 SL won despite a vulture flying through the windscreen.

The race team prepared a new version of the 300SL for the 1953 season.^[37] The 300 SLK would be lighter with a shorter wheelbase and larger wheels.^[37] The 300 SLK was given fuel injection and better brakes.^[37] Unfortunately, Mercedes prioritized its efforts to work on a new Grand Prix car, and the 300SLK was canceled.^[37]

Late '50s[]

Werner Engel won the 1955 European Rally Championship driving a 300 SL.^[41] Stirling Moss won overall at the 1955 Mille Miglia on a 300 SLR racing car while John Fitch driving a production 300 SL Coupe won his class^[42] The marathon rally Liege-Rome-Liege was won in 1955 by Olivier Gendebien^[43] and won in 1956 by Willy Mairesse.^[44] Competing in Class D, a 300 SL won the Sports Car Club of America championship three years running from 1955 to 1957.^[4]

Roadster[]

Roadsters were made for touring, not racing, but Daimler-Benz marketed the roadster by racing on American tracks. Since production began, the Sports Car Club of America could not admit the roadster as a standard model for the 1957 season. The roadster would have to compete in the sports-racing car Class D with other 3-liter cars such as the Maserati 300S, Ferrari Monza, and Aston Martin DB3S. The O'Shea/Tilp team used a lightened roadster with the front coil spring mounts being drilled and no fan and the inlet manifold welded of aluminum sheet and twin exhaust pipe outlets. The roadster, sometimes called the SLS, won the 1957 Class D Sports championship with triple the total points gained by its nearest challenger Carroll Shelby's Maserati.^[40]

After 1957[]

Horácio Macedo came second in the Rali Vinho da Madeira in 1960.^[45]

Bob Sirna, a previous president of the Gull Wing Group International organization set a new Bonneville Speedway F/GT speed record in 2016 in a highly modified Coupe, establishing a new high speed for a 3L Sport car of 190.759 mph (306.997 kilometres per hour).^[46]

Reception and sales[]

Sales quintupled in the model's second year but dropped off over the next three years.^[10] Roadster sales were initially high then leveled off to about 200 a year.^[10]

Production numbers[]

^[47][10]

Famous owners[]

Mohammad Reza Pahlavi, Wernher von Braun^[48] Rob Walker, Juan Manuel Fangio, Juan Peron, Tony Curtis, Pablo Picasso,^[49] Sophia Loren, Romy Schneider, Clark Gable, Glenn Ford,^[50] Briggs Cunningham, Luigi Chinetti, John von Neumann,^[47] Pierre Trudeau,^[51] Justin Trudeau,^[51] Paul Newman, Yul Brynner, Bernie Ecclestone, Ralph Lauren, Frank Lloyd Wright,^[52] Adrian Conan Doyle,^[53] King Abdullah II of Jordan, Natalie Wood^[54] have owned a 300 SL.

Legacy[]

300 SL beside the SLS AMG

A less expensive, 1.9-litre Roadster was introduced in 1955 as the Mercedes 190SL. The 230 SL followed the 190SL.

Subsequent generations of the Mercedes-Benz SL-Class have been continually produced such as the Mercedes-Benz W113 (1963–71) and the Mercedes-Benz R129 (1989–2001). However, the SL has since evolved to become a more autobahn-focused grand tourer due to increasing weight, especially with its optional V12 engine in later iterations.^[55] The last two generations of the SL are hardtop convertibles.^[56]

A 571 PS (420 kW; 563 hp) 6.2 l (380 cu in) V8 powered Mercedes-Benz SLS AMG made its debut in 2009 to be the spiritual successor to the 300 SL Coupe.^[57] SLS AMG production finished at the end of 2014^[58] and was replaced by the AMG GT with traditional doors and a much smaller twin-turbo V8 engine.^[59]

300 SL members are supported by the Gull Wing Group International which started in 1961.^[60]

The Wii U game Mario Kart 8 and its Nintendo Switch update, Mario Kart 8 Deluxe, feature a 300 SL Roadster.^[61]

References[]