The new BMW M3 Sedan and new BMW M4 Coupe

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2.  The balance of the overall concept: A blend of elements working in perfect harmony delivers outstanding performance, precision and agility.

Low-slung and broad-set, the new BMW M3 Sedan and new BMW M4 Coupe share  a finely balanced stance on the road. Indeed, the M-specific design of the two high-performance sports cars underlines their performance capability. Large air intakes and Air Curtains at the front end, exposed carbon-fibre- reinforced plastic (CFRP) and aluminium body components, and the diffuser at the muscular rear end are not merely design flourishes; they also fulfil functional roles in terms  of aerodynamics, cooling and weight saving.

Numerous aerodynamics measures integrated into all areas of the body.

The aerodynamics concept of BMW M GmbH models has always been one of the key elements in their development. The engineers need to channel the air around  the car to create the best  possible platform for dynamic excellence, while also ensuring the engine,  powertrain  and brakes  receive the requisite cooling even when operating under  heavy loads on the race track.

explains Albert Biermann, Head of Development BMW M GmbH. Elements like the Air Curtain and M gills with integrated Air Breather rearwards of the front wheels minimise turbulence in the front wheel arches. Together with the aerodynamically optimised exterior mirrors in twin-stalk style, they are also highly distinctive design features of the BMW M3 Sedan and BMW M4 Coupe and help reduce drag. These examples underline in familiar fashion the success of M engineers in reconciling the requirements of everyday use with the demands of action on the race track.

Sophisticated cooling concept for maximum performance.

The exceptional performance potential of the BMW M3 Sedan and BMW M4 Coupe places extremely exacting demands on temperature management in the engine  and peripheral assemblies. In order to ensure optimum operating temperatures in everyday use, on short journeys around town and out on the race track, the BMW M GmbH engineers have developed cylinder engine also includes an indirect intercooler, maximising charge pressure and engine output.

temperature water circuits, and the engine  and transmission oil (if the  M Double Clutch Transmission is specified). These ensure a consistent temperature balance and therefore high performance on the track as well as the road. An additional electric coolant pump  cools the turbocharger bearing mounts when the car is stationary.

Six-speed manual gearbox with throttle blipping.

The engine’s  power is transferred to the road via a standard six-speed manual gearbox  with robust  double-plate clutch. This unit is considerably more compact than its predecessor and 12 kilograms lighter. As a means of increasing shift comfort, the manual gearbox  uses innovative new carbon friction linings in its synchroniser rings. Dry sump  lubrication provides  an efficient supply of oil to all parts of the engine.  The gearbox  blips the throttle on downshifts – previously a feature  reserved for the M Double Clutch Transmission. This engagement speed control function improves the smoothness of the transmission, helps to enhance stability and was originally developed by motor sport engineers.

Seven-speed M Double Clutch Transmission Drivelogic with Launch Control.

The third generation of the M DCT sees the M engineers once  again setting the benchmark in terms  of power and race track capability without having to compromise on everyday usability. The optional seven-speed M Double Clutch Transmission with Drivelogic prompts the new high-revving turbocharged engine  into emotionally impressive feats. As well as changing gear automatically, in manual mode the transmission enables ultra-fast  gear changes with no interruption in the flow of power.

The integrated Launch Control function ensures optimum  sprinting performance off the line, producing acceleration figures that would be out of range  with the manual gearbox. Stability Clutch Control opens the clutch when the car is understeering to bring it back into line. And M DCT also includes functions like the Drivelogic modes that can be selected by the driver to give the BMW M3 and BMW M4 more comfortable, more economy-focused or even sportier characteristics. The additional seventh gear over the manual gearbox allows longer gear ratios – and delivers the efficiency gains you would expect as a result.

The properties of the extremely light yet impressively durable material CFRP have allowed the engineers to follow a fundamentally new approach in the manufacture of the drive shaft. Made from CFRP, this component feeds the engine’s  torque  from the gearbox  to the rear differential and works under extremely heavy loads – especially in high-performance vehicles. “The impressive stiffness and low weight of the CFRP tubing allow the drive shaft to be constructed as a single-piece unit with no centre bearing. As well as a weight saving of 40 per cent  over its predecessor, we have achieved a reduction in rotating masses and therefore improved drivetrain dynamics,” explains Albert Biermann.

Even more accomplished rear-wheel drive with Active M Differential.

Among the other components that add fresh polish to the dynamic repertoire of the BMW M3 Sedan and BMW M4 Coupe are the hollow lightweights yaw rate. Every driving situation is therefore precisely analysed and an impending loss of traction on one side of the car identified at an early stage.

The degreeis adjusted as required  within a fraction of a second, enabling wheel spin to be prevented on slippery surfaces, in instances where the right and left rear wheel have widely differing friction coefficients, in tight bends and when changing direction with particular vigour. Optimising traction in this way also provides  unbeatable driving stability in challenging conditions and allows impressively dynamic acceleration out of corners.

quenches the thirst of enthusiastic drivers for keen dynamics. While DSC intervenes as required  to counteract understeer and oversteer, M Dynamic Mode allows greater wheel slip and therefore easy drifting.

Owners with a taste for sporty and dynamic driving will appreciate this breadth to the cars’ handling, although  DSC will still step  in if the car ventures over the limits – unless it is switched off completely. Whichever setting the driver chooses, he or she remains  responsible for the car’s stability.

Aluminium suspension elements ensure sharper dynamics.

limit adjustability, agility and driving feeling, together with unbeatable traction and outstanding directional stability all without neglecting everyday usability. In order to achieve  these aims with the significantly increased performance capability of the new BMW M3 Sedan and new BMW M4 Coupe,  the axles of the outgoing BMW M3 have been redesigned with painstaking attention to detail.
Here again, low weight and a high level of rigidity for the axle systems are essential ingredients in ensuring the cars provide an ultra-dynamic driving experience. In the double-joint spring strut front axle alone, the use of a lightweight aluminium construction for components such  as control arms, wheel carriers and axle subframes saves five kilograms over a conventional steel design. Play-free ball joints and elastomer bearings developed specially for the BMW M3 Sedan and BMW M4 Coupe ensure an optimum  and direct transfer of forces both laterally and longitudinally. An aluminium stiffening plate, CFRP precision strut and additional bolted  joints between the axle subframe and the body structure all help to increase the rigidity of the front end.

Also lighter than the construction in the outgoing BMW M3 is the new five-link rear axle. All the control arms and wheel carriers are manufactured using forged aluminium, which reduces the unsprung masses of the wheel-locating components by around  three  kilograms compared with the previous model generation. The rigid connection between the rear axle subframe and the body – without the use  of elastic rubber  elements – is borrowed from motor sport and serves to further improve wheel location and therefore directional stability. “The double-elastic mounting for the rear differential within the rear axle subframe – which is bolted  to the body structure – has allowed us to achieve a new level of driving precision, but without neglecting comfort,” says Albert Biermann, citing another example  of the perfect symbiosis of pure-bred motor sport technology and excellent everyday usability.
The development of the tyres for the cars was incorporated into the construction process for the axles from the outset. For high-performance sports cars like the BMW M3 Sedan and BMW M4 Coupe,  in particular, steering feel and precision are the foremost considerations in the development of tyres for the front axle, alongside lateral stability and braking forces. At the rear axle, meanwhile, traction, lateral stability and directional stability take centre stage. For this reason, both cars will leave the factory on low-weight 18-inch forged wheels (front axle: 9 J x 18, rear axle: 10 J x 18) with mixed-size tyres (front axle: 255  mm, rear axle: 275  mm). 19-inch tyres are available as an option. The specially developed forged wheels  make a significant contribution to the reduction in the cars’ unsprung masses and, in turn, to the optimisation of dynamic qualities and efficiency. The experienced
M engineers have taken great care to ensure all the components between the steering wheel and tyres work together harmoniously and therefore provide maximum driving precision and lateral stability, along with good ride comfort.

Electric Power Steering with three settings.

The electromechanical steering system in the new BMW M3 Sedan and new BMW M4 Coupe represents a new development from BMW M GmbH and the critical component in the link between driver and car.

It offers the gifts of direct steering feeling and precise feedback. The integrated Servotronic function electronically adjusts the level of steering assistance according to the car’s speed, providing optimum  steering characteristics at all speeds. The steering for the BMW M3 Sedan and BMW M4 Coupe also offers the driver three  settings as standard, which can be selected at the touch  of a button. COMFORT, SPORT and SPORT+ modes allow the level of steering assistance to be adapted to suit the situation at hand and the driver’s personal tastes.

“Together, the rigid front and rear structures, precise axle kinematics and an impressively responsive electromechanical power steering system help to deliver the outstanding steering and handling characteristics of the BMW M3 Sedan and BMW M4 Coupe,”  sums up Biermann.

The optional Adaptive M suspension likewise comes with COMFORT, SPORT and SPORT+ modes, enabling the driver to choose between a more comfortable damper setting for urban driving, for example, a stiffer set-up for dynamic driving on country roads, and a third option that minimises body movements and maximises dynamic performance for use on the track.

With their supreme dynamic attributes in mind, the BMW M3 Sedan and BMW M4 Coupe also come as standard with BMW M compound brakes boasting impressive feel, outstanding stopping power and high resistance to fade. Far lighter than conventional equivalents, these brakes  contribute to a substantial reduction in unsprung masses and therefore help to enhance dynamic performance. Even lighter BMW M carbon  ceramic brakes  can also be specified as an option, their further optimised performance attributes equipping them  even more effectively for track use and giving them  even greater durability.