The famous American architect Louis Sullivan coined the phrase "form follows function" back in 1896. The idea made so much sense that it quickly spread to other design disciplines.
As aerodynamics exerts a huge pull on how a car is shaped and detailed, the fourth generation Brabus E V12 debuting at this year's Frankfurt Motor Show is a prime example of the mantra.
"We were in the wind tunnel experimenting with various detail refinements and tried covering the wheel arches," Uli Gauffres, Brabus' Development Chief, explains. "Of course you cannot cover the front arches as this would restrict steering movement, but just covering the rear arches produced a measurable improvement in the drag coefficient."
Car designers have been down this road before. The BMW 328 from the 1930s, the Jaguar XK150 from the 1950s, and the Citroën DS from the 1960s all subscribed to covered rear arches as a method of drag reduction; Honda is most recent manufacturer to use this on a production car.
But no manufacturer has made these parts from carbon before, and it's important to note that all the aerodynamic components on the E V12 made from this material are autoclaved, not carbon-look.
They consist of the new nose cone with its integrated airdam and separate air splitter, front arch air vents, side sills, rear arch extensions with detachable wheel covers, a bootlid edge spoiler and the rear underbody diffuser. The rear arches are attached by a quick release system that enables them to be detached in seconds for access to the wheels.
Brabus doesn't have a definitive drag coefficient figure as yet, but as the standard car's is 0.25 Cd, a number south of that would not at all be surprising.
Although cars tend to get heavier with each generation, Brabus has managed to pare weight from the W212 E-Class-based E V12. While its W211-based predecessor weighed 4,450 pounds, this one tips the scales at 4,365.
As always, the heart of the E V12 is its powerhaus V12 engine. The first and second E V12s, based on the W124 and W210 models, used Brabus' naturally aspirated 7.3-liter version of the M120 V12 (582 hp). The third-generation W211 had a 6.3-liter version with 640 hp. When the 730-hp Bullit came online in 2007, the E V12 was uprated accordingly.
The new numbers register at 800 hp at 5500 rpm and 1,047 lb-ft of torque at 2100 rpm. This level of twist is beyond the capabilities of the gearbox, rear axle-and indeed overall tire traction-to harness, so torque is electronically limited to 811 lb-ft.
The increased power, lower drag and reduced weight conspire to make the new E V12 quicker through the gears on the same 2.65 axle ratio, and also faster all-out. A limited-slip differential with 50-percent locking under acceleration helps traction.
The 2005 model ran past 62 mph in 4.5 seconds to a 198.8-mph top speed. The new numbers are 62 mph in 3.7 seconds and a projected 230-mph top speed.
Customer cars will be electronically limited to around 217 mph, as there is no tire at present that will allow a two-ton car to exceed that speed. Brabus is in discussion with tire manufacturers for special rubber that will allow the car to be fully extended.
Brabus has been happily extracting 730 hp from the Mercedes-AMG biturbo V12 for some time. Considering the all-new specially manufactured internals, it's a power level that works very well in terms of long-term reliability.
The extra 70 hp, equivalent to around 10 percent, required some innovative thinking and came about through many hours of development work on the flow bench and engine dyno.
"The 730-hp cap we've had on power output for the last three years was a direct function of air intake and intercooler limitations," Gauffres explains. "We were happy with our modified turbos and exhaust system at the time, but knew the intake and intercooler package was the key to further increases."
The latest E-Class's engine bay and new intercooler designs are key. This technology has effectively increased the E V12 engine's intercooling capacity by 100 percent and reduced backpressure by half. The taller bonnet allows the two very efficient air filters to be placed where they receive ram air via ducting from the radiator grille. This creates a sealed system with the hood shut and reduces the airflow path length compared to conventional tube ducting. The charge air temperature drop allowed the team to use a turbocharger with a larger housing, turbine and kompressor wheel. The exhaust manifold design was also revised with larger diameter pipes. The turbine housing is now directly connected to the manifold. The existing 200-cell metal catalytic converters are unchanged.
ECU remapping is ironically one of the most time consuming parts of the conversion as every minor ECU in the car has to be reprogrammed since it was originally designed to "handshake" with either a four, six or eight-cylinder engine.
Putting this kind of power to the tarmac through the rear wheels is a big challenge, even with the limited-slip differential providing 50 percent locking action under hard acceleration. ESP is recalibrated, but you don't want its traction control protocol coming in too early or it will simply cut power.
The Mercedes Airmatic suspension isn't up to the task-it can't react fast enough at these kinds of speeds-so Brabus replaced it with custom coilovers: progressive-rate springs and dampers with separate 10-way adjustable bounce and rebound. Handling is further improved by a 36mm increase in front and rear track, achieved through a combination of wheel offsets and spacers.
The E V12 seats four in comfort on ergonomically contoured sport seats. Quilted leather gives the floor and console their unique appearance while the dashboard, headliner and door armrests are finished in Alcantara.
The recalibrated speedometer reads out to 400km/h, with red numerals to highlight its very important function. The other instruments retain their white numbers, but now have red backlighting.
You would think that driving the E V12 would be like trying to tame a bucking bronco. Give it too much throttle and that would indeed be the case. But if you drive normally, it acts like it was born to V12 power.