kilometer magazine

celebrating european cars and motorcycles


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9 October 2009

In a recent made-up poll, nine out of ten newborns were able to correctly identify the Mercedes-Benz 300SL by name. One, a child obviously destined for greatness, even uttered the words “Thank you, Max Hoffman.” But we’ll get to that later. The 300 SL “Gullwing” is such a memorable car that we could think of no better way to kick off our Icon series.

As with many brilliant performance machines, the 300SL was born out of a motorsports effort and, more specifically, the desire to beat the stink out of Jaguar at Le Mans. After watching that company’s C-type dominate the 1951 race, Mercedes-Benz racing team manager Alfred Neubauer went to work on his world-beating racer with help from Rudolph Uhlenhaut, the man assigned to the W194 (as it was know internally) design.

For the sake of reliability and simplicity, the team started with components already in series production. To that end, the racecar borrowed its suspension and engine from the 300S sedan, known also as the “Adenauer” Mercedes. The aging production car technology ended there, however. To keep weight down, the team borrowed from airplane engineering, constructing a stiff tubular spaceframe that would be far lighter than a ladder frame. Inside the low, sleek chassis, the 300’s tall inline-six had to be canted 50 degrees from upright. Still, when the production 300SL was pieced together a few years later, the final hood height was too low for the engine, forcing designer Uhlenhaut to bend a long strake longitudinally into the hood above the valve cover. Seeking symmetry, he added a matching kink along the left side of the hood, inspiring the aggressive bulges still found on performance-oriented Mercs to this day, from the SLK to AMG models.

That’s not the only trademark 300SL detail born out of necessity, of course. The W194 racer was designed from the ground up with the sole purpose of going fast, meaning it ditched the popular speedster layout for a slippery, fixed-roof design. However, communication between engineers must have broken down somewhere between the tube chassis construction and the streamlining, because no room was left for doors. And not only would there need to be a big enough hole to get the driver out, but that hole also had to meet regulations by measuring at least sixteen inches by eight inches. That’s the size of hole that was cut, only instead of sacrificing rigidity by cutting down into the spaceframe, Uhlenhaut ordered them to rise up into the roof, meeting at a hinge directly in the middle. The competition was furious as this funhouse treatment of the rule, but it worked and the design stuck. An early reworking brought the doors down slightly further into the car’s sides, a move that added a kink in the sheetmetal below each window. This curviness inspired fans to coin the “Gullwing” name.

The racing SLs made their debut at the 1952 Mille Miglia, where they were beat by a fearless performance from Ferrari driver Giovanni Bracco. The M-B team certainly made up for that, however, with a one-two finish at the 24 Hours of Le Mans that same year. That racing season proved quite successful for the silver machines from Stuttgart, inciting a rivalry with Ferrari that the Italians were never given a chance to win. After the season, despite a new, updated car with incredible improvements, the powers-that-were at Merecedes refocused the motorsports effort on Grand Prix racing. Fortunately, all of Uhlenhaut’s improvements would see the light of day, only in the hands of paying customers.

Most notable among the new technology being prepped for the stillborn 1953 season was the 300SL’s fuel delivery system. Not only did it use fuel injection in place of carburetors, it used direct fuel injection, a technology we now know was about fifty years ahead of its time. Only in the past few years has the idea of the injectors blasting fuel right into the cylinders caught on, and now it’s used widely by Porsche, Audi, Volkswagen, Cadillac, even Chevrolet and Ford.

Bosch’s revolutionary system used on the 300SL was mechanically, as opposed to electronically, driven, using a pump on the side of the block that almost looks like a scale model of the engine block itself. A shaft connected to the timing gears drove a cam inside the pump, which in turn moved six little plungers in sync with the pistons, squirting gasoline at just the right moment. The fuel lines ran to injectors that filled the original spark plug holes, while the plugs were relocated from the side of the block to the top of the head. This injection system allowed space for incredibly long (seventeen inches) intake runners, boosting power at the top of the range.

To hear the 215-hp inline six fire up for the first time is as rewarding for the ears as the first up-close encounter is for the eyes. It roars to life with a sharp, firm chugachuga that sounds a bit like a freight train pounding along over the rails. But surprisingly, considering what we expect of injected engines, it showed a strong need for warming up before running confidently. The Bosch system did compensate for atmospheric conditions, but had no system to aid cold starts. The 300SL still used a manual choke, which it seemed to our ears was difficult to modulate perfectly.

Finicky is exactly how we wanted this motor to be, though. Born of a Le Mans champion, the road car spits and burbles and pops like a machine that’s restless as a toddler in church when stopped, but absolutely comfortable 100 mph later, hanging on to the lowest gear possible. It sounds like no other straight-six we’ve heard, and just knowing what sort of cutting-edge Fifties technology is at work makes the experience all the more religious.

Our visit with the King of Benzes may have never happened, though, if it weren’t for Max Hoffman. An Austrian living in New York, Hoffman’s claims to fame also included urging Porsche to build the 356 Speedster and BMW to develop a roadster, the iconic 507. As the only Mercedes-Benz distributor on the East Coast, he wanted the Gullwing in his showrooms as a halo car. He told the German management he’d sell 1000 easily and, according to a popular tale, even delivered a down payment for that same number of cars. Fittingly, the car, code-named W198, debuted at the 1954 New York Auto Show.

For as many things that didn’t change — the doors, the newly-developed direct-injection engine, the spaceframe, and the race car’s large drum brakes — many details were changed for the road car. The hood, which on the final racing prototypes was carried on up to the grille, was cut short and was hinged at the front. It was still made of lightweight aluminum, as were the doors and trunk, but the main bodywork was changed to steel for cost savings.

Instead of simple props to hold the doors in the up position, the production car used beautiful chromed hydraulic struts, while the door handles were given locks and a new flush-mounted design. Rolling windows couldn’t be added for obvious logistical reasons, but the production SL did feature removable glass that could be stowed in a set of bags behind the seats.

The SL’s front end design was also reworked to form its now-legendary face, the three-pointed star floating in the center of a horizontal chrome bar and the headlights lunging forward more than on the racers. Vents remained behind the front wheels but were given more brightwork, and flares were added to accent all four wheel wells. On the early car you see here, they were bolted on with a gasket separating them from the body; eventually, they’d be welded in place. Sporting options included racing-style knock-off wheels and an all-aluminum body, but very few were ordered that way.

Inside, the production Gullwing is a minimalist environment with all the necessary gauges and little more. The steering wheel was no longer removable, but it did flip down for ease of entry. The racing gabardine cloth remained but the shifter was moved rearward and shortened from its original size, a running change that happened just after production started.

In person, the Gullwing looks incredibly small, perhaps simply because it has such a huge personality in photos or because of how large cars are today or what we Americans expect from the bigger-was-better Fifties. The 300SL sits on a wheelbase an inch shorter than the current SLK, the brand’s smallest sports car. It’s the same height (51 inches) and the same width (70 inches) as that car as well, though at 178 inches, the 300SL outstretches the SLK by 17 inches, most of which is in the hood.

We also can’t hide our excitement seeing all the little details in action—the slender door handles flipping out, the doors swinging up, the steering wheel swinging down—the details really make this car, and not just those sketched out on paper. Even peeking down to see the fuel pump makes us grin from ear to ear.

Journalists of the Fifties were grinning similarly, as the 300SL toured the world being praised at every stop. Road & Track even went so far as to declare that “the sports car of the future has become a reality.” Even today the car uses elements not found in many sports cars. Aluminum is still reserved for only those companies willing to trade a bit of cost in the name of performance and direct-injection is just now spreading wide across the sports car market. The car’s weight—just over 2800 pounds—is quickly becoming hard for even the smallest roadsters to match as safety and convenience features take priority over all-out performance. And arguably, Mercedes-Benz itself hasn’t been able to match the SL’s beauty in the five decades since it debuted.

Consumers agreed as well. Max Hoffman’s 1000-car promise was easily met and by the time the hardtop SL gave way to its roadster counterpart in 1957, 1400 examples had been hand-built and delivered. The car never lost its luster—it remained a prized collector’s car and fine examples fetch upwards of a half-million dollars today.

Mercedes-Benz hungered for more, however, introducing a car that corrected each and every complaint from buyers. Because ingress and egress was difficult and likely never graceful (picture someone exiting a Lotus Exige today,) the 1957 300SL was a roadster featuring a collapsible cloth top and doors that extended further down into the car’s flanks. Because handling from the car’s rear swing axle was hairy at its limits, it was reworked to have lower pivot points and a horizontal spring was added to tame the monster. And to make it more affordable, a less complicated 190SL model was added, producing 105 hp. At the same time, the 300SL roadster’s engine was retuned to produce 250 hp. When the first generation of SL drew to a close, 1858 roadsters had been added to the car’s production total. Since the Gullwing, only the 1970s-era SLC and a very limited number of special-run and racing SLs have featured fixed roofs. The latest, of course, being the 2009 SL65 AMG Black Series.

Few cars have impacted the sports car world like the 300SL and even fewer have inspired a half-century of uninterrupted sporting heritage. The SL is to Germany what the Corvette is to America, or what the E-type-turned-XK is to England. And to think, it all started because one guy wanted to beat another guy in a silly little race.

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