More power, more performance and more style – the new BMW M3 has more of everything. The latest version of this world-famous sports car from Munich is beyond comparison in the world market. Quite simply because it offers the customer a level of performance clearly borne out from the start in the new coupé: 
 

BMW M3

343 bhp/252 kW straight-six power unit  with double-VANOS, 365 Nm/269 lb-ft,  0 –100 km/h in 5.2 sec,  fuel consumption 11.9 ltr/100 km (23.7 mpg Imp)

Even more than its predecessor, the styling of the new M3 reflects its outstanding performance and dynamic driving qualities even more clearly through its exciting design. But it retains its everyday driving qualities in full, remaining a high-performance car, which, through the sum total of its supreme qualities, will once again be the leader in its class. 
Athletic in style, elegant in looks.

At very first sight the new M3 exudes a sense of superb power, wide and muscular looks, as well as beautiful elegance. With its new front air dam with ellipsoid foglamps and extra-large cooling air intake scoops, it stands out clearly from all the other models in the BMW 3 Series range. The kidney grille, slightly modified in its position, blends with the new design of the front end.

Made of aluminium, the engine compartment lid is approximately 40 per cent lighter than the same unit made of steel plate. A particularly important factor is that despite this reduction in weight the engine compartment lid offers the same stiffness and crash safety as the steel plate unit in the “basic” Coupé. This was made possible using computer simulation clearly demonstrating how the geometric features responsible for stability affect the static and dynamic stiffness of the engine compartment lid.

The engine compartment lid on the M3 is characterised in particular by its new contours with the power dome, a small hump in the middle of the lid, providing room for the new M3’s engine. Again, this clearly characterises the overall style and appearance of the M3, without one single feature serving only a visual purpose alone. Instead, all modifications versus the standard model are based on the clear rule that form follows function, offering beautiful styling and design at the same time.

The body of the new BMW M3, including the wheel arches is considerably wider (plus 20 mm/0.79´´) and features air scoops with the M3 emblem on the front side panels. The wider body and flared wheel arches are needed to fit both the wider track as well as appropriate tyres and wheels. Indeed, the extra-wide 225/45 ZR 18 tyres at the front and the 255/40 ZR 18 tyres at the rear on newly designed M Styling double-spoke light-alloy wheels measuring 8 inches in width at the front and 9 inches at the rear provide a perfect match for this muscular appearance in the interest of optimum streamlining, clearly distinguishing the new M3 from the “standard” 3 Series coupé. Talking about dimensions, the new M3 measures 4.49 metres (176.8´´) in length, 1.78 metres (70.1´´) in width, and 1.37 metres (53.9´´) in height. The car’s wheelbase is 2.73 metres (107.5´´).

New M exterior mirrors in aspheric design and folding back electrically as an option whenever required. Special side-sill covers, as well as a streamlined rear air dam and a specially designed rear spoiler accentuate this powerful, dynamic look of BMW’s new M athlete. The exhaust system with twin chambers and four tailpipes, finally, clearly identifies this model as a member of the exclusive M Car range.

The interior – sporting and elegant all in one.

Benefitting from a typical BMW M instrument cluster with special scales on the instruments, the driver has a clear view of all the new M3’s  functions. Again in classic BMW M style, the circular dials so typical of BMW come on this car with red indicator needles. 
A feature carried over from the M5 is the rev counter with its variable warning zone: Whenever the driver starts the engine cold, orange light-emitting diodes (LEDs) come on as of an engine speed of 4000 rpm, then extinguish in steps of 500 rpm as oil temperature increases. As soon as there is only one orange and two red LEDs left on, the engine has reached its optimum operating temperature. A further standard feature is the oil temperature display. 

The newly designed M multifunction steering wheel has a padded, extra-thick rim, M stitching and thumb supports is not only pleasant to hold, but also ensures top quality all round. A footrest in aluminium as well as the door cutout strips with the M3 symbol round off the special look and style of the car’s interior.

The courtesy lights package, featured as standard comprises both the illuminated gearshift lever with its six-speed gearshift pattern and M logo as well as the interior mirror with its automatic anti-dazzle effect. Automatic air conditioning with separate temperature control for the driver and front-seat passenger comes as standard.

Passive safety matches with the high standard offered by the entire BMW 3 Series, frontal, side and head airbags featured as standard to protect the driver and front passenger, with two side airbags available as an option on the rear seats.

The clear design, colour and material “language” is again typical of BMW M, enabling the purchaser of the M3 to choose among three different design lines and combinations: a fabric/leather combination, a leather/Alcantara combination, or leather trim inside the car. Two special paintwork colours exclusive to the M3 are also new.

The new M sports seat with variable backrest width adjustment.

The new BMW M3 comes for the first time with sports seats featuring individual backrest width adjustment. The focus in developing these seats was to considerably enhance side support with a sporting style of motoring, without requiring drivers of different size to make any compromises in terms of seat comfort and relaxation on long distances.

In its mechanical configuration, the M3 sports seat is based on the all-electrical seat of the 3 Series coupé, including all its control elements. From the start the seat is carefully padded and upholstered to provide adequate longitudinal and side support also with a very sporting style of motoring. This is then enhanced by air chambers on the right- and left-hand side of the backrest, filled with air by an electric pump at the touch of a button (available as an option together with adjustment of the backrest contour and lumbar support).

Depending on the body size and personal preferences of the driver and front passenger, this allows optimum side support tailored to each individual. The chambers on each side are separated by an additional valve preventing any unwanted pressure shift in bends, with air flowing from the outer to the inner chamber and thus possibly contradicting the actual purpose of this backrest support.

The foam seat squab ensures a sporting, low seating position. Thanks to the variable side support provided by the backrest, there is no need in this case to provide any special contour at the side. And since the same design concept is applied at shoulder level, 
the sporting driver enjoys optimum freedom of movement despite the excellent side support.

The Power Unit of the M3.

The power unit featured in the new M3 excels in particular through its turbine-like surge of power combined with equally outstanding running smoothness and refinement, fortes which have long become the synonym of BMW six-cylinders the world over. And now the new engine adds new meaning to these supreme qualities, introducing the BMW M high-speed concept applying the standards also valid for the most demanding and sophisticated competition engines in the world, the power units to be found in Formula 1. It is important to note, for example, that the pistons of the new M3 power unit move at a speed of more than 24 metres per second at the maximum engine speed of 8000 rpm. For comparison, the crankshaft in a modern Formula 1 power unit rotates up to 18,000 times a minute, each of the 10 pistons covering a distance of approximately 25 metres per second.

Outstanding efficiency at all engine speeds and under all loads guarantees superior fuel economy in everyday motoring and a low level of emissions.In close cooperation with BMW AG, BMW M has developed a special engine management system for the M3 called MSS 54. Like the control unit on the previous model, this multi-processor system comes with two 32-bit micro-controllers and two timing co-processors operating now at a higher frequency in order to cope with even more complex function data and the higher maximum engine speed of the new model. This MSS 54 engine management unit is thus able to perform 25 million calculations per second.

The functions masterminded by MSS 54 include the timing control on the intake and outlet camshaft (high-pressure VANOS), permanent oil level control, the immobiliser, electronic throttle butterfly control, and an elaborate diagnostic system with various diagnostic routines for the workshop. Operating individually on each cylinder, this control unit calculates the ignition timing, the injection volume, and the injection timing for each load cycle as a function of engine load and speed as well as the gradient of load change. At the same time it also calculates and sets the optimum cam angles.

Optimum engine management ensured by a special in-house development from BMW M.
Cylinder-specific, adaptive knock control receives its knock signal from three sound body sensors, each sensor monitoring two cylinders. These cylinders are adjusted individually for knock management as a function of load points, applying a concept able to program the best ignition data throughout the ignition angle map. A switch on the instrument panel allows the driver of the M3 to choose a more sporting, that is a more progressive map curve in terms of gas pedal travel and the throttle butterfly opening. As soon as the driver activates this more progressive gas pedal control map, the dynamic transition functions on the electronic engine management switch over to a more spontaneous application. The more comfort-oriented control map, in turn, is activated automatically each time the car is re-started. 

Electronic throttle butterfly control is based on engine torque and output data, meaning that the driver’s wish for power and performance is measured on the gas pedal by means of the potentiometer and translated into a specific request function. This request function is then adjusted by the power and torque manager by adding the power signals from the auxiliary engine units and is then aligned to the maximum and minimum output and torque curves allowed by the Dynamic Stability Control (DSC) and Engine Drag Force Control (EDFC). The target output and torque calculated in this way is then maintained at the desired level, taking the current ignition angle into account.

While the engine is warming up, the catalytic converter is heated as quickly as possible by the system intervening in the VANOS camshaft management, ignition, fuel injection, and the electrical secondary air pump, the output and torque manager making the necessary corrections. A further point to be added in this context is that this engine management system complies in full with all on-board diagnosis standards currently in force. 

Thrust, an all-important factor.

The engine specialists at BMW M are convinced that a fast-revving normal-aspiration power unit is ideal for a sports car expected by the ambitious motorist to provide outstanding performance and acceleration in all situations on the road. The crucial point when it comes to acceleration is the thrust available on the drive wheels, that is the rear wheels in the case of the M3, as with every BMW. This thrust can either be provided by a large engine running at low speeds and with a “long” overall transmission ratio or by a smaller engine running at high speeds and with a “shorter” overall transmission ratio.
The high-torque concept provided by large engines involves significant disadvantages in terms of weight and engine dimensions, since the engine and all components on the drivetrain are inevitably very large and heavy due to the high torque. Application of the high engine speed concept was therefore essential in creating the new M3, a coupé combining dynamic and agile behaviour with the performance of a sports car.

106 bhp per litre thanks to the high engine speed concept.

The straight-six power unit displacing 3,246 cc is now featured for the first time worldwide on all national variants, developing 343 bhp (252 kW) in ECE-trim and 333 bhp in the US model at 7900 rpm. Although engine capacity has been increased by only 1.4 per cent over the previous model, the high engine speed concept boosts engine output by 6.9 per cent and torque by 4.3 per cent. Improvement of the cylinder charge cycle and the improvement of flow conditions within the entire engine and drive system have increased output per litre from 100 to almost 106 bhp.

Despite its high running speed, the engine offers a large useful speed range, with no less than 80 per cent of its maximum torque at just 2000 rpm. A few interesting figures in this context are the M3’s acceleration to 100 km/h in just 5.2 seconds and acceleration in fourth gear from 80 to 120 km/h in a mere 5.4 seconds.

Exemplary fuel economy and emission management.

The high standard of efficiency gives the engine not only a very high level of output and torque, but also excellent specific fuel economy reaching its peak at 235 grams/kWh. Optimisation of the valve drive system in the interest of minimum friction and the increase in compression to 11.5 : 1 makes the new engine even more fuel-efficient than its predecessor, particularly in the lower load range.

In the ECE cycle the new M3 requires just 11.9 litres on 100 kilometres (23.7 mpg Imp), at the same time easily meeting the EU3 and LEV emission standards. The engine of the M3 is designed for 98 RON fuel, but adaptive knock control also allows the engine to run on unleaded premium down to 95 RON.

Providing an even better equilibrium of the fuel-air mixture, adaptive idle speed synchronisation offers a further reduction of fuel consumption with the engine running at low speeds near the idle range. In conjunction with the rapidly adjusting high-pressure double-VANOS, the optimisation of the injection valves as well as the configuration and position of the valves themselves allows a further reduction of specific fuel consumption especially when running under high loads at low speeds. In the upper load and speed range, the smoother flow conditions in the cylinder charge cycle help to reduce specific fuel consumption.

An all-new development on a proven foundation.

The high engine speed concept was only one of the reasons for the completely new development of the M3 power unit. Further important objectives also to be reached through the new concept were

• lower weight
• a wider useful speed range
• more torque and power
• worldwide use of the engine fulfilling all pertinent legal requirements in terms of emissions, noise control, etc.

The basic engine with an even lighter crankshaft revving even more freely than before.
Running at high speeds and under high combustion pressure, the crankcase is made in perlite casting technology. With a stroke of 91 millimetres (3.58´´) and a bore of 87 millimetres (3.43´´), the graphite-coated cast aluminium pistons with a specially machined crown allow a compression ratio of 11.5 : 1. The pistons are cooled by oil injection jets directly connected to the main oil duct. The connecting rods, in turn, are forged cracked steel units, as on the former model. The cylinder head with anti-friction followers and 
crossflow cooling.

The single piece four-valve cylinder head is cast by BMW in a steel die and features integrated air ducts for secondary air injection serving to enhance the efficiency of the catalytic converter to a maximum level. Valve drive is provided by anti-friction followers offering significant advantages in terms of low friction and moving masses over cup tappets, given the limited space and small dimensions available. Compared with cup tappet valve drive, oscillating masses are reduced by 30 per cent. This allows a reduction of valve spring forces and, accordingly, of friction losses and fuel consumption despite the increase in maximum engine speed from 7600 to 8000 rpm. The diameter of the intake valves is 
35 millimetres or 1.38´´, the diameter of the hollow-drilled sodium-filled outlet valves 30.5 millimetres or 1.20´´.

Valve clearance is adjusted by platelets resting directly in the upper spring plate. With the adjustment of clearance only being required in major inspections, the adjustment intervals may be extended up to 40,000 kilometres. The exact interval required is calculated individually in each case according to the car’s running conditions and is shown to the driver in the instrument cluster.

Higher engine power also means greater cooling requirements, particularly near the combustion chamber. The cylinder head on the M3 therefore features a crossflow cooling concept ensuring an even distribution of temperature within the cylinder head: Coolant flows from the crankcase through the outlet side across the cylinder head and on on the ring-slide thermostat via a collector pipe on the intake side. This principle is so efficient that the amount of water in the cylinder head has being reduced versus the former model.

VANOS: 
variable cam adjustment for an optimum gas charge cycle.

BMW VANOS variable cam adjustment on the intake and outlet camshafts, which made its world debut in the BMW M3 back in 1992, again ensures an optimum gas charge cycle in the new M3 power unit. In practice this means more power, greater fuel economy, and cleaner emissions with less pollutants.

The operating principle is simple and straightforward: The chain wheel driven by a duplex chain linked to the crankshaft is connected with the camshaft by a helical-toothed shaft able to move freely in axial direction. In such an axial movement of the shaft, the helical gearing causes a relative radial movement between the camshaft and the chain wheel, allowing the timing angle on the intake camshaft to vary by 60° and the angle on the outlet camshaft by 46° crank position. Axial adjustment of the gear shaft is ensured by an adjustment piston.
Engine oil is pre-pressurised to an operating pressure of 115 bar by a radial piston pump integrated in the VANOS housing. Map-controlled high-pressure adjustment guarantees short adjustment times, providing the optimum timing angle geared to the ignition timing
and injection volume at each operating point as a function of load and engine speed.
Reliable oil supply even in extremely fast bends.

Oil is supplied to the engine for lubrication by a gear-wheel pump. With the oil sump positioned behind the front axle subframe and on account of the high level of lateral  and vertical acceleration the car is able to achieve, the new BMW M3 features a quasi-dry sump system. Just for explanation, a dry sump system is an oil circuit in which the lubricant is drawn out of the oil sump and held back for an interim period in a separate reservoir.
The reason for choosing this elaborate and sophisticated system is the outstanding performance offered by the M3 on the road: Due to the specific location of the sump and the position of the engine fitted at an angle of 30o to the right, oil is no longer able to flow back into the sump under high lateral acceleration in left-hand bends and when braking hard. This is why the pressurised oil pump is connected with a return pump extracting oil from the right-hand side of the small oil sump at the front and pumping it into the large oil sump at the rear. The rear oil sump is completely closed for all practical purposes, the re-flow openings and the extraction point on the pressurised oil pump are geared exactly to the acceleration conditions to be anticipated in the car.

Six individual throttle butterflies with electronic management.

The most significant highlights on the intake side are the six intake funnels in a large air collector and the six individual throttle butterflies. Both the air collector and the funnels are made of a light composite material with 30 per cent glass fibre and form one complete unit. The intake funnels are specifically matched in terms of their diameter: length ratio and were developed with the help of a simulation program by BMW’s Formula 1 Racing Department.

As opposed to the former model, the new BMW M3 now features six individual throttle butterfly housings instead of three double housings. To ensure, first, an even more sensitive response of the gas pedal at low speeds and, second, a direct response of the vehicle as soon as the driver floors the gas pedal, the throttle butterflies are masterminded by an all-electronic “brain”. Electronic operation of the throttle butterfly ensures furthermore that the transition, say, from overrun to part load and vice versa is even smoother and more harmonious than before. 

Exhaust system reduces counter-pressure by 40 per cent.

The two fan manifolds consist of multiple ducts equal in length and diameter and suitable for use in both right-hand-drive and left-hand-drive cars. In designing the exhaust system, BMW’s engineers sought consistently to keep counterpressure to an absolute minimum. Accordingly, the exhaust system extends back in two chambers until reaching the silencer. Each exhaust pipe contains two trimetallic-coated catalytic converters ensuring minimum pressure loss, a high standard of mechanical stability, and a quick response after starting cold. Since the car does not require a spare wheel, there is enough space for a rear-end silencer in semi-shell design with a volume of 40 litres. Thanks to this overall configuration, exhaust gas counterpressure has been reduced versus the former model by no less than 40 per cent.

Six-speed gearbox and final drive in the same format as on the M5.

The six-speed manual gearbox had been carried over from the former M3 with virtually no modifications. Together with the final drive, it enables the new M3 to exceed the 100-km/h-mark in second gear. The sixth gear, in turn, allows the M3 to reach its electronically limited top speed of 250 km/h or 155 mph at moderate engine speeds. 
The final drive comes with the same dimensions as on the BMW M5 and therefore requires a new rear axle subframe with modified dual-elastic suspension. Here again, reflecting the high engine speed concept, the final drive has a transmission ratio of 3.62 : 1, allowing full use of the engine’s power and performance.

The Suspension: “Faster than the Engine”.

One of the principles applicable to every BMW M Car is that “the suspension must always be faster than the engine”. Clearly, this was a particularly demanding task for BMW’s suspension specialists in this case, considering the high engine speed concept of the new M3.

It is also a fact, however, that BMW’s engineers were able to proceed from an excellent starting point: The suspension of the new M3 is a consistent development of the suspension and chassis featured on the former model. And this is a car with driving characteristics still acknowledged as the benchmark in the sports car segment, for example as the “Best Handling Car” in the words of the experts writing for “Car and Driver”, the famous US magazine. In practice, of course, the very stiff bodyshell  of the 3 Series coupé, the large share of light aluminium axle components , and the virtually perfect  front-to-rear weight distribution of almost 50 : 50 provide ideal conditions for undaunted driving pleasure with BMW rear-wheel drive.

Despite the slight increase in the car’s dimensions, BMW’s chassis engineers have succeeded in enhancing the handling qualities of the former model to an even higher level, while at the same time retaining the same supreme standard of everyday driving qualities.
In addition, they have improved the car’s driving characteristics particularly in winter, thus avoiding the restrictions in winter so typical of a “classic” sports car.

The front axle: light, stiff and extremely precise.

The single-joint spring strut front axle is roughly identical to the front axle on the former model in terms of its basic kinematic data. The particularly stiff connection of the suspension components to the body of the car makes a decisive contribution in increasing the M3’s steering and driving precision. To keep unsprung masses to a minimum, the front track control arm is made of aluminium.

This stiff connection to the body of the car, the modified elastokinematics, the wide track (1,508 millimetres/59.4´´) and the direct rack-and-pinion steering in conjunction with the ergonomically designed steering wheel rim ensure a standard of driving precision an agility never seen before.

The front axle support bearings have been developed especially for the new M3 with separate mountings for the springs and dampers guarantee precise alignment of the wheels and keep out any roughness or unsmoothness from the road below. The geometric configuration allows a smaller kingpin inclination and a larger castor angle, the new M3 thus giving the driver a clear message of its superior agility and performance without in any way neglecting the necessary standard of comfort.

To improve driving agility and efficiently transmit the dynamic wheel forces to the body of the car, BMW’s engineers have developed a new “thrust plate” for the BMW M3. This is a 3-millimetre-thick aluminium plate bolted on to the bearing points of the two front track control arms, thus providing additional stability on the road. Driving tests confirm that this new feature is even more efficient in compensating the forces acting on the car under high lateral acceleration, which is one of the M3’s most outstanding fortes. The result,
of course, is an even higher standard of dynamic driving performance and superior behaviour on the road.

The rear axle:
extremely stable and comfortable at the same time.

The kinematic configuration of the central arm rear axle has also been carried over by and large from the car’s excellent predecessor. Now, however, the upper track control arm is made of aluminium and the rear wheel track has been increased in the same way as on the front axle (1,525 millimetres/60.0´´). Stiff connection of the rear axle components to the body of the car is ensured by a V-shaped tie-bar.

The central arm rear axle on the new BMW 3 Series coupé provided most of the outstanding foundation for the new M3. The reinforced drivetrain nevertheless required elaborate modifications on the rear axle subframe as well as a new bearing concept for the final drive.

All suspension and damper components have been carefully tuned and matched to one another for sports motoring. With body sway amplitudes and the sway angle being kept to a minimum, the driver will enjoy a safe feeling even at racing speed on the Nürburgring, lapping the track very quickly indeed. The car’s extreme yaw stability after a load change in bends or when applying the brakes in a bend is maintained consistently by the new M3 all the way to its very high extreme limit, even without the DSC system cutting in for extra stability. Both roll comfort and roll noise, finally, are far above average for such an active-driving sports car.

Specially made wheels and tyres.

Specially developed high-speed tyres measuring 18 inches in diameter and 225/45 ZR 18 on the 8-inch front wheels and 255/40 ZR 19 on the 9-inch rear wheels ensure precise and stable transmission of high side and longitudinal forces through their special compounds and dimensions, at the same time providing satisfactory roll comfort on both dry and wet roads and giving the driver a clear message on the dynamic state and behaviour of his car. As an option 19-inch tyres measuring 225/40 ZR 19 at the front and 255/35 ZR 19 at the rear running on 8- and 9.5-inch-wide forged aluminium wheels will soon be available, giving even greater emphasis to the car’s sporting character.

The aluminium wheels fitted as standard excels in particular through their shadow chrome surface provided by a highly sophisticated and very demanding paint application process. A polished surface tinted grey on the spoke walls, emphasizes the sophisticated forging technology on the optional 19-inch wheels. The extended hump or EH geometry of the wheels, prevents the tyres from slipping down into the well base under loss of pressure, thus ensuring the safe stopping principle characteristic of all BMW M Cars.

Tyre pressure warning system featured as standard.

The further improved tyre pressure warning system (TPW) permanently monitors the wheels when turning and triggers an alarm as soon as the loss of pressure exceeds approximately 50 per cent. Even with this reduction in pressure, the tyres still remain firmly on the rims thanks to the extended hump design, allowing the driver to stop the car without problems. Following a puncture, holes measuring up to 6 millimetres in diameter can be sealed by the second-generation M Mobility System (MMS), the driver then going on without having to change wheels. This makes it unnecessary to carry a spare wheel also for reasons of weight, the replacement of a complete spare wheel by the M Mobility System saving more than 20 kilos.

Compound high-performance brakes restraining BMW M Power whenever necessary.
Wherever there is a lot of drive power, there must also be a lot of brake power. Precisely this is why the new BMW M3 comes with an extra-large high-performance brake system comprising compound brakes in floating arrangement. The inner-vented friction-ring on the brake disc is connected through cast-in stainless steel pins in floating arrangement with the aluminium brake disc pot. This considerably reduces the thermal loads and forces acting on the brake discs, increasing the service life of the discs accordingly. Cross-drilling of the friction ring reduces the weight of the brake discs even further by 0.7 kilos on each front wheel and 0.8 kilos on each rear wheel versus the weight of conventional single-piece brake discs.

Benefitting from extra-large grey-cast-iron brake discs measuring 325/28 millimetres (12.80/1.10´´) in diameter and thickness at the front and 326/20 millimetres (12.88/0.78´´) at the rear, as on the BMW M5, the new BMW M3 offers impressive stopping power. Supported by a 9-/10-inch tandem booster, the M3 is able to achieve deceleration of approximately 11 metres/sec2, thus reducing its stopping distance to 35 metres when braking all-out from a speed of 100 km/h.

To express this in other terms, the new BMW M3 decelerates from 100 km/h to a complete standstill in only half the time it takes to accelerate from 0 to 100 km/h. This again ranks the BMW M3 high up in the superior segment of thoroughbred sports cars also in terms of its brake performance.

New DSC with a switch-off function for the first time also in the BMW M3.

In certain situations classic sports cars of the calibre of the BMW M3 have a hard time getting their superior power on to the road, simply because of excessive slip on the rear drive wheels. To further improve traction and driving characteristics in winter and to ensure everyday driving qualities also in bad weather, BMW’s Dynamic Stability Control (DSC) has been specially modified for the new M3. Particularly on slippery roads, DSC enhances driving safety in abrupt manoeuvres or whenever a dangerous situation suddenly looms
up ahead in a bend. To make such critical situations easier to handle, this superior system is able in such a case to apply the brakes specifically on each individual wheel of the car.
Special extensions of the DSC logic were nevertheless necessary for the new BMW M3. The spontaneous response of the M3’s engine and the short final drive ratio, for example, require extremely fast and sensitive control of both the engine and the brakes. The first objective in this process is to maintain yaw stability also on surfaces with a low frictional coefficient, the second objective is to avoid any excessive curtailment of the car’s additional power through the variable M differential lock, naturally offering the driver that sheer
driving pleasure so typical particularly of this very dynamic BMW.

New on the M3:  the variable M differential lock.

So far BMW M Cars have come with torque-sensing self-locking differentials with up to 25 per cent locking action and a constant basic locking force. To explain the need for this philosophy, the two drive wheels of a car cover a varying distance in bends, the inner wheel not having to travel as far as the outer wheel. This distance is set off by the axle differential.
Whenever required, a differential lock builds up locking action, for example if one of the two drive wheels is threatening to spin, say on a slippery surface. Particularly sports drivers will appreciate the differential lock, since it enables them to benefit from the positive characteristics of rear-wheel drive above all when driving in sporting style on roads with an average to high frictional coefficient.

Good for excellent driving in winter.

On a torque-sensing differential lock the total drive force the system is able to transmit is based on the power the wheel with the lowest frictional coefficient is able to convey at any given point in time.

If the frictional coefficient is very low, however, for example on snow, gravel or even smooth ice, the traction benefits provided by such a conventional differential lock concept are limited by the restricted support forces under such conditions.

Precisely this is why the engineers of BMW M, cooperating with GKN Viscodrive GmbH, have developed an entirely new system for the new M3, the variable M differential lock able to offer a decisive improvement of traction even in the most demanding situations on the road, that is with an extreme difference in frictional coefficient between the drive wheels. In combination with the fine-tuned DSC system and the car’s well-balanced weight distribution, the variable M differential lock gives the new M3 driving characteristics previously regarded as quite impossible with a rear-wheel-drive sports car particularly in winter.

Maintaining drive power in every situation.

A further advantage of the variable differential lock is that it builds up an increasing locking action between the drive wheels immediately as soon as the wheels start to turn at a different speed. As a result, a wheel running under less load such as the inner wheel in a fast bend on a mountain road cannot cause drive forces to “collapse” completely, meaning that the car retains its forward drive in all situations.

The variable M differential lock works according to a clear and straightforward principle: The differential speed between the drive wheels whenever one of the wheels is relieved of its load or runs on a very slippery surface generates pressure spontaneously in an integrated shear pump. This pressure is transmitted by a plunger to a multiple-plate clutch, conveying drive forces to the wheel with better grip as a function of the difference in speed. In an extreme case the full drive force of the engine, provided the frictional coefficient is sufficient, may be transmitted via the wheel with the better coefficient to the road beneath. Once the difference in speed between the two wheels decreases again, pump pressure will also decrease and the locking action is reduced accordingly. This self-regulating pump system is maintenance-free and is filled with highly viscous silicon fluid. 

The big advantage for the driver of the BMW M3 is that he or she is able to set off much more smoothly and efficiently on a poor surface with very different frictional coefficients for the two drive wheels, since he now has more traction. A further point is that the variable 
M differential lock increases both handling and driving stability by a significant margin, adding to the driver’s safety and driving pleasure on the road. 

The test: taking a fast trip through “Green Hell”.

Contrary to “classic” sports cars, BMW M Cars are driven by customers all over the world throughout the whole year under all kinds of conditions, mainly, however, in a very sporting style. This is simply because the BMW M3 offers a very high standard of everyday motoring qualities and practical value. Clearly, this also means that the new M3 required a very elaborate and intensive test programme.

The first component tests for the suspension and drivetrain of the new M3 started in the early development phase when careful simulation studies were carried out. Particularly components such as the front axle track control arm, the front axle support bearing, the thrust plate at the front end of the car and the new variable M differential lock, all of which differ from the “standard” components on the basic coupé, thus achieved a high level of maturity right from the start in the concept phase.

The examination of complete axles on BMW’s dynamic wheel test bed is an efficient interim step in testing the various components before they are fitted on the car itself. In this process a complete axle is put to the test on a dynamometer simulating the northern circuit of Nürburgring over a distance of 5,000 kilometres. 

Obviously, such a rigorous test demands the utmost from the compound high-performance brake system and the wheels of the new BMW M3. The wide range of climate tests for the M3 extended from heat tests in Death Valley, USA, or in the high-altitude desert of Namibia at +45 °C all the way to cold-weather tests in Finland or Canada at –40 °C. The various drive cycles, in turn, ranged from stop-and-go traffic in Los Angeles all the way to extreme full load tests at BMW’s own proving grounds in Miramas, France. To verify the high engine speed concept, special 40,000-kilometre endurance runs were held on this oval high-speed track, giving the engine and the entire drivetrain roughly the same load and stress conditions as 200,000 kilometres on the Autobahn.

A particularly tough test highlight for all BMW M models is the 8,000-kilometre endurance test on the northern circuit of Nürburgring known as the “Green Hell”. The load forces acting on the suspension components under such conditions are up to 20 times as great as under normal driving conditions with the customer at the wheel. And lapping the Northern circuit of Nürburgring in times well under 8½ minutes, the new M3 was just as fast as thoroughbred touring race cars just a few years ago, winning the 24 Hours of the Nürburgring in the process.

In summary, the BMW M3 created by BMW M is once again an absolutely outstanding if not to say a unique sports coupé, a car with incomparable style and character. Thanks to its high-speed normal-aspiration power unit, the new M3 runs as spontaneously and responsively as a thoroughbred sports car, at the same time offering the elegance, everyday driving qualities and comfort of a 3 Series coupé, plus the value, efficiency and environmental compatibility you would not expect of a high-performance car of this calibre – quite simply high performance and supreme precision of a fascinating kind.