Journal: 6.3 Liters & 300 HP Make The 300SEL A Two-Ton Supercar

6.3 Liters & 300 HP Make The 300SEL A Two-Ton Supercar

By Alan Franklin
May 2, 2013

America may have invented the term “hot rodding”, but as a concept its appeal is universal, with no one nation rightfully able to claim itself the inventor—as long as there’s been motorized vehicles there’ve been power-hungry madmen looking to extract more oompf from their engines.

An all-time classic hot rodding example comes from Germany, as many of them do, this particular time in the form of Mercedes Benz’s legendary 300SEL 6.3. Widely regarded as the daddy of all mega-engined luxobarges, the 6.3 began life as the pet project of enterprising MB engineer Erich Waxenberger, who was blessed with the divine inspiration to shoehorn a 300 HP (SAE) M100 V8 from the 600 Grosser plutocratmobile into the relatively modest engine bay of the W109. The result was a nearly two-ton portable smoking room capable of 0-60 in 5.7 seconds—in 1966!

Rather surprisingly, a conservative Mercedes green-lighted the genteel monster and launched it at the 1968 Geneva Motor Show, ostensibly in order to better utilize production capability at the M100 engine plant, but perhaps more likely to show the world what MB engineering could achieve given the right mix of ingredients.

It certainly made an impression, easily capable as it was of cruising for extended periods of time at 200 km/h with five occupants cradled in luxury and safety—this at a time when the average family sedan struggled to achieve 100 MPH. Utilizing self-leveling air suspension, the 6.3 gave a remarkably smooth and quiet ride (perhaps only challenged by Citroen and their otherworldly DS—coincidentally Citroen’s olepneumatic suspension provided inspiration for a similar system employed in the 6.3’s predecessor, the mighty 450SEL 6.9) even for a luxury car, let alone one capable of performance greater than most contemporary exotic sports cars. Inside the lavish cabin, lucky occupants were treated with buttery leather, deeply polished wood veeners, chromed fittings, and dashboard architecture of a style and quality that can only be attributed to a more elegant and refined age.

The infamous AMG “Red Pig” finished 2nd at 1971’s Spa 24-Hour endurance race, an astonishing result for such a large and heavy car—it even featured an automatic transmission! Its engine was enlarged to 6.8 liters and made approximately 420 HP, and was reportedly capable of pushing the porky racer to 62 MPH (100 km/h) in just 4.2 seconds. It might have finished first were it not for its excessive thirst for fuel necessitating frequent pit stops, and its excessive weight necessitating frequent tire changes—there may indeed be no replacement for displacement, but there’s no cheating physics when it comes to the corners, either.

Replaced by the 450SEL 6.9 in 1975, both cars can be credited with paving the way for the type of supercar-baiting, 200 MPH+ übersedans and wagons that AMG (and indeed, M) now specialize in. The fact that performance has increased by only approximately 40% in nearly half a century speaks volumes as to how incredible the 6.3’s numbers were during their heyday—way back at the height of the Cold War, the Space Race, the Civil Rights Movement, and when the average computer took up several large rooms. What an achievement.

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4 years ago

I am here for the share this update to all web users just need to access sync microsoft here and save the all function for batter work.

Jim Levitt
Jim Levitt
5 years ago

The beige one pictured here looks suspiciously like my old one, Hellas and all!
(45 year old analog pictures, sorry).
US 6.9s were ugly, but more so they were much more boring to drive. Very smooth but they lacked the grunt of the 6.3s

Burt Munro
Burt Munro
10 years ago

An absolutely wonderful car and, though the W116 6.9 was more ‘civilized’, it too is capable of brutality – even in contemporary terms. The M100 is a wonderfully strong design with forged components, sodium filled valves, and a dry sump straight from the factory.

Standalone EFI and twin turbos on an otherwise stock (save for exhaust) US-Spec 6.9 can readily -and reliably- put 600+ to the rear wheels. Replace the 6.9 nomenclature with “turbodiesel’ and it becomes a wonderful q-ship.

Rip Curl
Rip Curl
10 years ago

The 6.3 and later the 6.9 were awesome cars. A few years back the Mercedes Classic Center in California had a 6.9 with less than 2,000miles on it. The price was almost $200K proving that time capsule cars occupy their own market share.

Years earlier I was on the track in a Ferrari 355 and was kept in sight on the straight by a 6.9. It was a seriously fast car and totally stock.

Andre C  Hulstaert
Andre C Hulstaert
10 years ago

How do you guys do it, another car I owned and which I regret selling. Mine was a very early one, VIN # 000002 ! It was silver and had no AC, which I regretted. It was a wolf in sheepsclothing. I was then living in a place where 95 \% of all Mercedes were Diesels and made quite an eyebrow rise in disbelief with my acceleration, which was, for that time impressive. It was utterly comfortable, in its own Teutonic way, having firm seats. I remember, at one point I was to go to a collector car swapmeet. The 6.3 was really the only car available. So, reluctantly, i loaded it up with my things, the spacious trunk was filled and the overflow on the back. Many very heavy things. The meet was about 100 miles away. I drove up there as if there was no load on the car and did it in one hour flat !
It had tremendous performance and roadholding to par. But it was not a subtle car, it took a long time to break loose, but when it borke loose, it was without warning and very sudden and brutal. I really never dared to push it to its limits as the speeds at which it broke loose were so high and it was so sudden I feared not being able to catch it. But then, on the other hand the speeds being so high it was more of academic value when it owuld break loose. The 6.9 was much more civilized, more in keeping with its luxury status. As I said the 6.3 was a wolf in sheepsclothing a true racer in street trim.
Then engine was literally shoehorned in the enginebay designed for a six. this with all the “pleasantness” which brings putting a wide V8 in a narrow sixcilinder bay. Externally one could distinguish the 6.3 by its longer wheelbase. The front cradle was moved forward abut 2 inches to clear the sump the V8, and provide a bit better grip too as a bonus putting the center of gravity a tad more to the rear (if this was measurable by the seat of the pants, I doubt it).
I have mane fond memories of that car, its successor, which I sampled, the 6.9 with the hydraulic Citroen licensed suspension, had lost much of its appeal and was much more civilized, less of a “hotrod”
Again, I attach a few snapshots of this car. And, again, I apologize for the poor quality them being scans of old negatives and not really color corrected or blemishes removed. I will do that one day and publish them on my site with other interesting cars i had to good fortune to own.

Mr Edward Mann
Mr Edward Mann
10 years ago

Hey! Aren’t you the same Andre C Hulstaert that owns Photography In Motion?