Following the motto “more is better,” Brabus became famous for relentlessly enlarging displacements of Mercedes-Benz engines in pursuit of ever-greater performance figures. An iconic example of this approach is the W140 600 SEC 6.9, and this was only the starting point. After thoroughly enjoying one of these nineties tuning royalties, Motorcar Journal visited the headquarters in Bottrop to talk with Ulrich Gauffrés, the mastermind behind every Brabus creation for several decades.

In these times of eco-influencing and climate advocacy it is of course anything but acceptable to blast through traffic in a hulking big Benz with a gas-guzzling V12, weaving between commuting EV disciples and flooring the throttle at every opportunity, just to revel in the phenomenal sound and the sensation of 705 Nm of torque.

I couldn’t care less though, because I’m sitting behind the wheel of a childhood dream and have zero interest in the opinions of self-proclaimed visionaries who consider themselves enlightened, yet need to shield themselves from the horrors of reality with Bluetooth headphones—lest they become overstimulated and spiral into a panic, demanding a safe space.

For that matter, the interior of this Brabus is highly recommended, because it does not get quieter or more soothing than this. Observing the world around me from this luxurious cocoon, I notice that no one gives the hulking black coupé a second glance. This, figuratively speaking, used to be the power of Brabus. Despite outrageously powerful engines and exclusivity, you can glide through traffic in complete anonymity, no one realising that the car passing by is more valuable and rare than, say, an Aston Martin, Rolls-Royce, or Lamborghini.

‘From a friend at Mercedes-Benz I borrowed a crankshaft and got on a plane with it to visit our crank supplier in the UK’

Tuning icon

Brabus was able to create this flagship after Mercedes-Benz launched the 600 SEC at the North American International Auto Show in Detroit in January 1992 with the internal reference code C 140 E 60. At that point Brabus already had their 6.9 engine ready, because the M120 V12 made its debut a year before in the 600 SEL sedan at the 1991 Geneva Auto Show. With 48 valves and CAN bus technology this V12 was very advanced and in standard configuration it developed 408 horsepower from 5.987 cc and a torque figure of 570 Nm. That was not enough for Brabus and even though it was still a relatively small company, they managed to put themselves firmly on the map by developing an upgraded variant that would go down in history as one of the icons of the tuning world.

For the story behind the development of this mighty 6.9 V12, we visited the Brabus headquarters in Bottrop to talk to Ulrich-Joachim Gauffrés, who now operates as a Senior Consultant for Brabus after retiring in 2021.

‘I started at Brabus in 1985 after working as an engineer on turbocharger and compressor technology at Daimler in Stuttgart,’ Gauffrés begins. ‘Brabus was still very small, with fewer than ten employees, and many people were surprised that I left a stable and promising job at Daimler for what looked like an uncertain future.’

What makes it even more surprising is that Gauffrés’ meeting with Brabus founder Bodo Buschmann was a coincidence.

‘In 1984, I was meeting the Dutch turbo specialist Willy Mosselmann for Daimler at the Automechanika trade show in Frankfurt. We met at the Brabus booth, and when Herr Buschmann heard that a Daimler engineer was on his stand, he came over for a chat. A year later, I moved to Bottrop, and this shows how seemingly small things can have a big impact in life,’ Gauffrés recalls, alternating between German and English.

Gauffrés continues by explaining that Brabus initially worked predominantly on four- and six-cylinder engines, while AMG focused more on the big models and V8 engines.

‘Brabus and AMG were definitely competitors back then, but we focused on our own segments. The takeover by Daimler was the big game changer because all of a sudden, AMG lost its freedom and had to comply with the stringent regulations of the new parent company. That is how the top segment became available to us almost overnight, and we gladly took full advantage of that.’

The most important step in that regard came when Gauffrés saw technical drawings of a future Mercedes-Benz V12 in a German technical trade magazine called MTZ (Motortechnische Zeitschrift).

‘For tuning companies, it is paramount to keep the time between the launch of a new model or engine and the availability of the tuned variant as short as possible, so you can be the first on the market. Based on the drawings and specifications in the magazine, I made a prototype from papier-mâché to work out the possible margins.’

Gauffrés’ expression changes from serious to cheeky, as he reveals, ‘From a friend at Mercedes-Benz I borrowed a crankshaft and got on a plane with it to visit our crank supplier in the UK. Based on this original crank and my calculations, they milled a new crankshaft. With new pistons, conrods, and later on, a lot of machining on the engine block, we eventually had our V12 with 6.9 liters.’

Squealing and smoking

Only one word is needed to describe this engine: perfection. Initially Brabus offered the 6.9 in every Mercedes-Benz that came with a V12 from the factory. So not just the 600 SEC, but also the four-door 600 SEL and the 600 SL (R129). Later, Brabus even offered the 500 E (W124) with a V12, amongst others (see text box 500 E 7.3 S below).

The most impressive aspect of this 600 SEC Brabus is the relentless shove in the back, while you have no other clues as to how fast you are going, unless you check the speedometer. That is how I came to the shocking conclusion that I may have broken the local speed limits—on multiple occasions and by a considerable margin…

‘Power is often a byproduct of an engine with high torque, so powerful cars almost always have high top speeds.’

It is evident that this powerhouse has no trouble pushing towards 300 km/h (190 mph), as speeds of up to 200 km/h (120 mph) are a picnic for this Autobahn stormer. When pulling away and at low speeds, it is advised to feather the throttle, because even with standard ASR (Antriebsschlupfregelung, or traction control), the 285 rear tires on 19-inch Monoblock wheels stand no chance against the might of 705 Nm and express their struggle by squealing and smoking vigorously.

The power delivery of this large V12 is wonderfully progressive, and with a little self-control, you can be outrageously quick while the passengers remain oblivious to the actual pace. What makes this Brabus a dream car for lovers of craftsmanship and traditional mechanical engineering is the fact that no turbo compressors and hardly any software fiddling were used. In the nineties, the use of turbos at Brabus was as far in the future as commercial space travel or digital currency trading.

In an era when excess was regarded as a form of prestige, Gauffrés developed engines according to a motto dictating that lots of engine capacity can only be replaced by lots more engine capacity.

‘I always had direct contact with most customers, and many said they wanted more power when they actually wanted more torque. This mostly became evident during test drives, because torque gives the sensation of fast acceleration, whereas power simply offers a higher speed. The latter is often a byproduct of an engine with high torque, so powerful cars almost always have high top speeds.’

Since the golden days of this V12, tuning has changed dramatically, and Gauffrés believes the automotive industry has passed the peak. He is not necessarily referring to the rise of electric cars, but more so to the trend of ever-smaller combustion engines with increasingly high turbo pressure to meet absurd emissions regulations invented by politicians vying for voters and media attention.

This leaves a relatively small margin for only the best and most experienced tuning companies. Gauffrés explains that many so-called chip tuners make claims that are not realistic, and that it is relatively easy for an experienced engineer to debunk them with calculations—as he has done on multiple occasions.

Brabus operates completely differently, and this has resulted in an impressive reputation, now upheld by Constantin Buschmann after his father’s premature death in 2018.

‘The Dutch customer left his car and a wad of cash that he pulled from his pocket, and we went to work’

With Brabus now employing 450 employees in Germany and maintaining a vast global network, we are curious how the current geopolitical situation is affecting the business model. Gauffrés’ reaction is as calm as it is direct: ‘It has basically no effect on us. We have waiting lists in all our major markets, so we can sell more than we can produce. If sales in, for instance, Russia decline, we can shift to other regions and still have more demand than supply.’

There is no doubt that Brabus is in a fortunate position. However, the future looks less bright for fans of large combustion engines with Guinness Book of World Records performance levels. Unfortunately we have to conclude that the best is no longer ahead of us, but we can safely state that the pinnacle of Gauffrés’ career has turned into a milestone in German tuning history.

More is better – 7.3 and 7.3 S variants

During the development of the 6.9, Gauffrés knew there was even more potential in the M120 V12. “At a certain point, you just have to stop the development and start production so you can make a profit.” Not long after the 6.9, the 7.3 followed, with 387 cc more capacity as a result of the bore and stroke increasing to 91 x 93 millimeters. The result was an increase to 530 horsepower at 5,750 rpm and a maximum torque of 754 Nm at 3,750 rpm. This improved the 0 to 100 km/h acceleration by 0.3 seconds to 5.3 and bumped the top speed from 304 km/h to 318 km/h.

But there was more… Gauffrés found additional margin in the cylinder heads, while sharper camshafts and different valve springs were installed. Combined with new catalytic converters, this new 7.3 S was the ultimate Brabus variant of the M120, delivering 582 horsepower at 6,000 rpm and 772 Nm at 4,000 rpm. The result was a top speed of 330 km/h and a sprint from 0 to 100 km/h in 4.9 seconds.

This was at a time when a carbon-fiber supercar like the Ferrari F50 offered 520 horsepower and ran out of breath at 325 km/h. Just imagine one of the most desirable and expensive sports cars of the nineties being pushed to the limit on the German Autobahn, when suddenly a black “taxi” creeps up in the rearview mirror, signalling the exotic supercar from Maranello to move out of the way…

500 E 7.3 S

A rather mysterious but highly impressive Brabus was the 500 E with the 7.3 S engine. “A very loyal customer from the Netherlands drove a 500 E that we had equipped with a 6.5 V8, but he still wanted more power. One of our salesmen jokingly suggested that we should stuff a V12 in it,” Gauffrés chuckles. “I was called downstairs because the Dutchman asked if that was really possible,” he adds, hilariously mimicking the customer’s Dutch accent in German. “After I explained that we’d need some time and some budget, he left his car and a wad of cash that he pulled from his pocket, and we went to work. The cooling system caused a great deal of headaches, but eventually, we managed to get it all working after restructuring the firewall and the engine bay,” Gauffrés recalls cheerfully.

The result was a monster of an E-Class, and according to the retired engineer, Brabus made two, possibly three, of these cars. Later on, the 7.3 S would also be used to power the W210 E-Class, the W163 ML, and even the X204 GLK, collecting a string of Guinness World Records in the process and cementing Brabus’ reputation as the Emperors of Excess.