This winter morning in 2004, a few snowflakes spun between two rays of sunshine on the Mercedes private circuit in the heart of Stuttgart. In a very warm shed, one of the rarest road cars awaits us, but also one of the most formidable produced by the brand with the star. : the 1955 Mercedes 300 SLR coupe. Exceptional, knowing this Mercedes is exceptional in more ways than one. Underneath its standard 300 SL suit, this “R” variant hides a true eight-cylinder Formula 1 Mercedes-derived racing engine with Fangio at the helm in 1954 and 1955. extremely rare. that an owner, even a carmaker, agrees to entrust the steering wheel of such a rare piece to anyone. In addition, in almost 70 years of life, this 300 SLR has known just about thirty drivers … and two journalists … We cannot thank Etoile enough for this exceptional brand of trust.
It takes a long preparation
Obviously, for this test, we are accompanied. In this case by Gert Straub, the engineer responsible for the maintenance and use of the car. He is the one who starts the warm-up procedure. Turn on the ignition key, turn on the fuel pump, and start the starter – deuce, I’ve never heard such a noise! Compulsory competition, admission and escape cannot be more direct. It doesn’t look like anything familiar, it’s not music, but it certainly impresses, it even lands. First a few minutes of stabilized speed at 3,000 rpm, followed by three more gas strokes up to 6,000 rpm, and the engine is silent. No, no problem. But once the engine is hot, you need to put “cold” spark plugs, the only ones capable of ensuring operation at a stabilized temperature.. A mechanic opened a large hatch at the bottom of the right front wing and started changing the 16 spark plugs! Yes, in addition to using an innovative direct mechanical injection, this eight in line has a dual ignition.
A meeting under surveillance
Change of spark plugs done, the 300 SLR coupe is coming to me. Despite the butterfly doors, access requires a bit of flexibility, which is not my forte. To make matters worse, a huge transmission tunnel (about 70 cm) separates the brake pedal from the clutch pedal, because the engine block, tilted to the left side to promote aerodynamics, imposes the passage of the axle of polarization transmission under the driver’s seat. . Without a seat belt, sitting with my legs well apart, my hands resting on a huge steering wheel, I am concerned about the quality of the brakes.. “These are four large ventilated drums with hydraulic assistance. It works great with a warning“Gert Straub said with a smile,”Attendance is proportional to speed. It brakes very well above 200 km / h, but at low speed … better pumping and pressing very hard! For the gearbox, the five gears are synchronized, but still crunch a bit. And then the grid is a little special: first at the top left, second at the bottom, third at the front, fourth at the bottom right, and fifth at the front. Oh, another thing, the clutch is vintage. Therefore, it is forbidden to make him skate. You set 3000 rpm and then release suddenly. Here we go ?“
ten minutes of grace
Okay, here we go, 3,000 rpm, I let it all go: almost without losing revs, the 300 SLR coupe takes off strongly. If this 8-cylinder doesn’t like to run below 2,500 rpm, beyond 4,000 rpm, it shows amazing vigor and really explodes beyond 6,000 rpm., and up to the switch located at 7,800 rpm. It is true that thanks to its light chassis and its body in magnesium and aluminum alloy (80% -20%), this 300 SLR coupe weighs just over 1100 kg. But even 50 years later it is rare for athletes to be able to accelerate so strongly, and without losing grip despite a bitumen close to 0ºC.
Evil, this engine is also for the ears. Because after ten minutes of this shock treatment, a persistent whistle made me regret rejecting the noise cancellation plugs. If despite a hard but quite precise steering, the chassis seems to digest without too much difficulty the 310 hp and not too tight curves, braking inevitably dates this silver arrow.. No biting, mandatory pumping and insufficient power – this is definitely the weak point of the car. Maybe, as Gert told me, it improves above 200 km / h, but out of respect for this almost singular object, as much as for lack of courage, I didn’t want to try it.
Deprived of competition due to the dramatic accident that claimed the lives of 81 spectators at the 24 Hours of Le Mans on June 11, 1955, Rudolf Uhlenaut, the designer of this unique boat, later worked on the development of cars. road, then on the C 111 equipped with a rotary piston engine. However, he did not abandon his two 300 SLR coupes, which he would use for a long time as ultra-fast service cars. Not knowing that one of them would become the most expensive car in the world in 2022 …
1955 Mercedes 300 SLR Coupe data sheet
- Engine: 8 cyl. online, 16s, 2982 cc
- Power: 310 hp at 7,400 rpm
- Torque: 317 Nm at 5,950 rpm
- Transmission: rear, 5-speed mechanics.
- Dimensions (L / A / W): 4.35 / 1.75 / 1.21m
- Deposit: 155 l
- Weight: 1117 kg
- Top speed: 284 km / h
- Average consumption: approx. 30 l / 100 km