History · 1938–today
The twelve-cylinder war.
Stuttgart built the fastest twelve-cylinder machines on earth, then put them away for half a century. It took a surprise from Munich to bring them back — and once they returned, Mercedes never let go again.
At eight o'clock on the morning of 28 January 1938, on the public autobahn between Frankfurt and Darmstadt, Rudolf Caracciola drove a silver streamliner through the flying kilometre at 432.7 km/h — a speed no car would beat on any road for seventy-nine years. Behind his shoulders sat a Mercedes-Benz V12.
Then Stuttgart put the twelve away. For half a century the company that had built the fastest twelve-cylinder machines in the world offered its customers nothing grander than a V8 — until a rival four hours up the autobahn forced its hand, and started the most patient war in the German motor industry.
Chapter I · 1930–1945
Records and war.
The record car was a monster in a tailored suit. Under the fully enclosed silver body of the W 125 Rekordwagen sat a 5.6-litre V12 of 736 PS — and no radiator opening at all, because the engine drank its cooling from a tank of ice and water instead. Every seam was filled, every duct deleted; its drag coefficient of 0.157 would embarrass almost every car on sale today.
The twelve was racing, too. For the three-litre Grand Prix formula of 1938, Stuttgart built the W 154 around a 60-degree V12 that revved to a shriek no supercharged eight could match. Caracciola took the 1938 European Championship with it — the high summer of the Silver Arrows.
War turned the same architecture upside down. The DB 600-series aero engines — inverted V12s hung beneath aircraft wings, with direct fuel injection years before any road car — powered much of the Luftwaffe, and their story belongs to the darkest chapter in the company's history.
And on the road? Nothing. The grandest pre-war Mercedes, the 770, made do with a supercharged straight-eight; a German limousine with twelve cylinders wore a Maybach Zeppelin badge instead. When peace returned, the V12 vanished from German passenger cars entirely — a crown left lying in the road for forty years.
- Record, km/h
- 432.7
- PS, record V12
- 736
- Drag coefficient
- 0.157
- W 154 title season
- 1938
28 January 1938 · Frankfurt–Darmstadt
432.7
km/h over the flying kilometre — set on a public autobahn by a Mercedes-Benz V12, and unbeaten on any road for the next seventy-nine years.
Chapter II · 1986–1991
The Munich surprise.
In 1986 BMW launched the E32 7 Series, and a year later dropped the hammer: the 750i, powered by the 5.0-litre M70 V12 — the first German production twelve since the war. Munich had picked up the crown Stuttgart had left in the road, and the 300 PS saloon walked straight past every Mercedes on the price list.
In Untertürkheim the shock was total. The next S-Class was nearly finished — and suddenly it wasn't good enough. The board took a decision that would define the company for a decade: hold the finished car back by eighteen months, re-engineer the engine bay, and answer twelve cylinders with twelve cylinders. Not matched. Exceeded.
The answer was the M120: six litres, four camshafts, forty-eight valves, an aluminium block with silicon-etched bores and forged connecting rods — 408 PS and 580 Nm, delivered with the menace of a closing library door. Where BMW had built a smooth engine, Mercedes had built a statement: the most powerful German production saloon engine of its day.
It debuted at Geneva in March 1991 in the 600 SEL, flagship of the W140 S-Class — a car so thoroughly over-engineered that its double-glazed side windows became legend. The badge on the boot lid said 600. The message to Munich said everything else.
- Munich's opener
- 1987
- PS, BMW M70
- 300
- PS, M120
- 408
- Nm, M120
- 580
Chapter III · 1992–1999
Twelve cylinders everywhere.
The M120 spread through the range like a rumour. In 1992 it dropped into the SL 600 — four hundred silken horsepower in a roadster — and into the vast 600 SEC coupé. For customers of a certain temperament, the 1990s Mercedes catalogue suddenly had one correct answer at the top of every page.
It nearly powered a supercar of Stuttgart's own. The C112 study of 1991 hung the V12 amidships behind a gullwing cabin; around 700 buyers put money down before Mercedes, mid-recession, decided the timing was wrong and returned the cheques. The engine would have to find its supercar somewhere else — and it would.
Meanwhile Affalterbach treated displacement as a suggestion. AMG bored and stroked the twelve to 7.0 and finally 7.3 litres: the SL 73 AMG made 525 PS — more than a Ferrari 550 Maranello — in a roadster with air conditioning and a Becker radio.
The wildest twelve wore racing numbers. For the 1997 FIA GT Championship, AMG built the CLK GTR around the M297, a 6.9-litre descendant of the M120 — and the 7.3 found immortality a year later, when a quiet Argentine in Modena chose it for a car he would call Zonda.
- SL 600 arrives
- 1992
- Litres, AMG's biggest
- 7.3
- PS, SL 73 AMG
- 525
- CLK GTR
- 1997
Why twelve
Zwölf.
A 60-degree V12 is two straight-sixes sharing a crankshaft — the only classic layout in perfect primary and secondary balance. It needs no tricks to fake serenity; it simply has none of the shaking forces lesser engines spend their lives fighting. Stuttgart's obsession was never really about power. It was about silence.
Chapter IV · 1999–2012
Silk, thunder, Maybach.
Emissions law retired the M120 from the S-Class in 1999, and its successor showed how the twelve's job had changed. The M137 was smaller and softer — 5.8 litres, single camshafts, three valves per cylinder, 367 PS — an engine tuned not for war but for wafting. Purists sniffed. Chauffeurs approved. It lasted barely three years.
Then Mercedes armed the twelve again. The M275 of 2003 bolted two turbochargers to 5.5 litres, and the arms race resumed at a higher altitude: 500 PS and 800 Nm, delivered from just above idle in total, unbroken calm.
It also gained a new throne room. The revived Maybach 57 and 62 of 2002 carried the M285, a twelve tailored in Untertürkheim for the double-M badge — up to 612 PS in the S models, hauling two and a half tonnes of lambswool and legroom.
And for those who wanted thunder with their silk, AMG built the 65s: 612 PS and a capped 1,000 Nm in the S 65, the SL 65 and eventually even the G 65 — the most powerful production V12s Germany had ever sold, their full torque never unleashed, rationed to protect the gearbox.
- Biturbo era begins
- 2003
- PS, M275
- 500
- Nm, 65 AMG
- 1,000
- PS, Maybach S
- 612
Chapter V · 2013–today
The last kingdom.
The final evolution, the M279, arrived with the W222 S-Class — six litres, twin turbochargers, and in the S 65 AMG a full 630 PS. But by now the twelve had outlived its argument: AMG's own V8s were just as fast, lighter and cleaner. Everyone expected Stuttgart to do the rational thing.
Munich did. In June 2022 BMW built its last twelve-cylinder car — twelve examples of the M760i badged “The Final V12”, sold only in America — and closed the chapter it had opened in 1987. After thirty-five years, the war's instigator left the field.
Stuttgart stayed. The Mercedes-Maybach S 680 still carries the M279 today: 612 PS and 900 Nm, arranged around one small badge on a front wing. Euro 7 has now pushed the twelve out of Europe — the armoured S 680 Guard excepted — but it lives on in the United States, China and the Middle East, and Mercedes has publicly committed to building it into the 2030s.
And the fiercest twelves still leave Affalterbach in wooden crates. Every Pagani Huayra and Utopia is powered by a bespoke Mercedes-AMG V12, hand-built a few workbenches from where the 65s were born. The last army of the twelve-cylinder war answers, as it always has, to Stuttgart.
- BMW's last V12
- 2022
- PS, S 680
- 612
- Nm, S 680
- 900
- Litres, M279
- 6.0
Eight decades of twelve.
From an ice-cooled streamliner on the A5 to the last V12 in series production — the long reign of the Mercedes twelve.
1938
The record
Caracciola's W 125 streamliner hits 432.7 km/h on the public autobahn — a road-speed record that stands until 2017. Its V12 makes 736 PS.
1987
The challenge
BMW's 750i brings the first post-war German production V12. Stuttgart holds its finished S-Class back by eighteen months rather than answer with a V8.
1991
The answer
The 600 SEL debuts the M120: 6.0 litres, 48 valves, 408 PS — the strongest German saloon engine of its day, and the heart of the W140.
1999
The soft twelve
The M137 replaces war with waft: 5.8 litres, three valves per cylinder, 367 PS. It lasts three years before the arms race resumes.
2003
The biturbo age
The M275 brings turbochargers: 500 PS in the S 600, 612 PS and 1,000 Nm in AMG's 65 models — and the M285 enthrones the twelve in the Maybach 57 and 62.
2026
The last twelve
Euro 7 exiles the V12 from Europe, but the Maybach S 680 keeps the M279 alive elsewhere — and Mercedes has pledged twelve cylinders into the 2030s.
Epilogue
The crown stays on.
BMW began the war and BMW left it; Mercedes never did. Thirty-five years after the Munich surprise, the only German luxury saloon still sold with twelve cylinders wears a three-pointed star, and the small V12 script on a rear pillar still means exactly what it meant in 1991: someone in Stuttgart refuses to lose an argument.
The twelve was never the rational choice — not in 1938, when it drank iced water; not in 1991, when a V8 would have done; not today, when almost nothing justifies it beyond the way it feels. That is precisely the point. Empires build monuments, and Untertürkheim's is made of twenty-four valves per bank, perfectly balanced, idling somewhere below the edge of hearing.