2003 BMW M3 CSL

A new sports car now embodies the very core of the BMW brand in its most original style – the M3 CSL. Taking up the heritage and legendary success
of BMW’s famous lightweight coupés which gained fame in touring car racing back in the -70s, the engineers of BMW M have once again created a purist, thoroughbred sports car consistently designed and built to the highest standard of excellence.

In recognition of the fact that the weight spiral constantly going up can only be brought to a halt by radically reducing all moving masses, BMW M’s engineers, in developing this new car, have turned a thrilling lightweight concept into reality. For the new BMW M3 CSL is not only more powerful than the already very dynamic M3, but is also a lot lighter and therefore even more nimble.

In developing the M3 CSL, however, BMW M did not focus on the radical reduction of weight alone. On the contrary, the task the designers and development engineers gave themselves was to create a car full of purist driving dynamics, a car absolutely pure in every respect, down to the very last component. And the result, finally, is unique, absolutely unmarred driving dynamics and a purist character.

The BMW M3 CSL thus combines supreme agility with the ultimate driving experience. With its outstanding power-to-weight ratio of only 3.85 kg/bhp, this new car moves into an entirely new dimension. So the engineers at BMW M are quite sure that this sports car is able to break the 8-minute sound barrier on the legendary Northern Circuit of Nurburgring, the ultimate benchmark in driving dynamics.

Intelligent Lightweight Technology

The formula BMW M’s specialists have followed in creating this dynamic driving machine is intelligent lightweight technology: This means consistent reduction of weight by using the most appropriate materials at the right point. Carbon-fibre -reinforced plastic, one of the most important materials in Formula 1, for example, not only reduces the overall weight of the car (weighing approximately 110 kg (243 lb) less than the standard M3, the M3 CSL has an overall weight of just 1,385 kg (3,054 lb), but also allows even higher speeds in bends particularly through the use of this lightweight material at the extreme ends of the car.

Right from the front the M3 CSL, through its newly designed, muscular front air dam made of carbon-fibre -reinforced plastic (CFP) with an additional engine air intake on the driver’s side demonstrates clearly that it is built for supreme performance of the highest calibre. Flaps also clearly visible from outside serve additionally to reduce front axle lift by a significant margin.

At the other end of the car the newly designed rear lid made of sheet moulding compound (SMC), together with the integrated spoiler, also serves in conjunction with the CFP rear diffuser to significantly reduce lift forces.

The intelligent lightweight technology so typical of the M3 CSL is demonstrated very clearly by the roof also made of carbon-fibre-reinforced plastic easily
recognisable as such. This large component built by specialists at BMW’s Landshut Plant is not only some six kilos lighter than a conventional roof, but also, through its exposed position, lowers the car’ s centre of gravity.

Focusing on their quest to reduce weight, the engineers at BMW M took a close look at virtually every component of the M3, in each case using the most suitable materials in order to save weight. As a result, the M3 CSL even comes with glass-fibre plastics otherwise used for aerospace applications such as endless-glass-fibre thermoplastics serving as the structural material for the through-loading system and on the rear bumper supports.

Engine of the M3 CSL.

The straight-six power unit already featured in the standard M3 owes its exceptional performance to BMW’s high-speed engine concept. This concept allows a particularly short transmission ratio giving the car superior power and performance throughout the entire speed range, six individual throttle butterflies ensuring that the engine responds perfectly to the gas pedal whenever required.

Also revving up easily and smoothly all the way to 8,000 rpm, the power unit of the M3 CSL offers an even higher standard of all-round performance. An all-new air intake system with an extra-large air collector made of carbon-fibre -reinforced plastic ensures an ample flow of air to the 3.2-litre power unit, the intake manifolds with a much large diameter taking in fresh air through the large air scoop on the left-hand side of the front air dam enabling the engine to breathe even more freely, without the slightest throttle effect.

The camshafts with their longer valve opening times also help to boost the power of the engine to an even higher level than before. To reduce the forces required for removing burnt combustion gas from the combustion chamber and thus increase the useful engine load accordingly, the exhaust valves have been modified once again in their geometry, the flow of gas also benefitting from the funnel-shaped pipe intakes leading into the rear silencer. And again reflecting the lightweight philosophy of the CSL, the entire exhaust system is made of pipes with even thinner walls at the side.

The result of this successful fine -tuning is maximum output of 360 bhp (265 kW) at 7,900 rpm, with maximum torque of 370 Nm (273 lb-ft) at 4,900 rpm. This equals output per litre of no less than 111 bhp, an extremely high figure for a normal-aspiration power unit and, incidentally, the highest output per litre of any production six -cylinder in the world.

The M3 CSL’s Special Gearbox.

To provide an ultra-fast gearshift with a smooth, uninterrupted surge of power, the new M3 CSL comes exclusively with BMW M’s Sequential M Gearbox with Drivelogic. An in-house development by BMW M, this special gearbox based directly on Formula 1 technology is naturally an integral part of the car’s overall concept. Which is no surprise considering that under optimum conditions SMG is able to shift gears in just 0.08 seconds.

The well-known benefits of SMG Drive logic include the option to shift gears either through the shift lever or through paddles on the steering wheel, the option to change over from the sequential to the automatic mode, and the choice of no less than eleven gearshift modes tailored to specific requirements on the road.

This modern transmission also offers a wide range of additional, practical functions such as launch control. Also referred to as the acceleration assistant, this function enables the driver to set off perfectly from a standstill with the gearshift lever in a specific position chosen in advance, thus benefitting from the car’s full potential when accelerating. And now this function has been refined to an even higher standard in the new M3 CSL: Once the driver activates the acceleration assistant, he no longer has to shift gears himself when subsequently sprinting from zero to the top speed of the car, since SMG Drivelogic sees what the driver plans to do and shifts the six gears itself at exactly the right point shortly before the engine reaches the rev limit.

Outstanding Agility

It goes without saying that a car as thrilling as the new M3 CSL requires the right kind of chassis and suspension. After all, the driver should really feel the agility of this car, agility should be an important part of the CSL driving experience. So in developing this dynamic suspension and chassis system, the engineers at BMW M again focused on motorsport, which is no surprise considering the very long list of racing wins and achievements by BMW touring cars in more than four decades.

the front springs are one winding shorter and both the spring and damper rates have been re -tuned all round in view of the car’s lighter weight, both the compression and rebound strokes being modified in the process. Like the front track control arms on the standard M3, the rear track control arms are now also made of aluminium and come with ball instead of rubber bearings for even better lateral dynamic guidance (uniball joints). In all, these improvements give the M3 not only uncompromising directional stability under all conditions, but also extremely good cornering qualities with very little body sway. And at the same time they significantly reduce the weight of all chassis and suspension components.

The M Track Mode

Apart from the SMG paddles, the driver of the M3 CSL will find another special feature in the three-spoke M sports steering wheel with its rim finished in Alcantara to provide a perfect grip – the M Track Mode switch on the right-hand side. Pressing this switch, the driver activates an additional DSC function presented clearly by a new signal in the instrument panel.

This special DSC Dynamic Stability Control mode allows the driver to use all the car’s longitudinal and lateral acceleration up to the physical limit, for example on the race track. In this case stability control will only intervene when the M3 CSL reaches the absolute limit, an optical signal telling the driver that the system has become active (as is the case with DSC).

Conclusion

Conclusion

Given its outstanding power-to-weight ratio, its supreme agility and driving precision, the new M3 CSL not only enters a new dimension of dynamic motoring, but also opens up the door for new solutions in technology, convincingly presenting a unique synthesis of intelligent lightweight technology and high performance – a modern sports car which, through the sum total of its truly outstanding features, lives out the innermost world of the BMW brand: sheer driving pleasure in its purest form.

In Detail

Keyword: 2003 BMW M3 CSL