M3 Lightweight Concept Car: Built for Speed

With this concept car BMW M shows that the awesome performance of the production M3 is by no means all that that platform has to offer. True to M's racing heritage, the modified 3.2 liter in-line six produces more than 350 horsepower. The six-speed transmission features BMW's Sequential Manual Gearbox (SMG) with Drivelogic. The extra power of the M3 CSL is combined with a near 450 pound weight reduction. To make the best of the new-found power and lighter weight,19 inch wheels and tires cover 18 inch brakes for superior handling and braking.

BMW at the 2001 Frankfurt Motor Show
09/04/2001

Built for Top Performance: BMW M3 CSL Lightweight Concept Car.

This will really make the hearts of all sports car enthusiasts skip a beat. Presenting the M3 CSL, BMW M is proudly highlighting the concept of a lightweight sports car at the 2001 Frankfurt Motor Show – a truly unique driving machine resting on wide wheels and impressively proving the potential of intelligent weight reduction. This is clearly borne out by three figures describing the fortes of this prototype not only to the connoisseur: Weight reduction of about 200 kilograms, power-to-weight ratio under 3.5 kilos per horsepower, lap time on the northern circuit of Nürburgring less than eight minutes.

This phenomenal lap time is the result of a consistent concept based on "intelligent" lightweight engineering: The optimum combination of materials and components using the most suitable material for each component and its specific requirements. This strategy is directly connected to BMW’s Formula 1 technology carried over to the road by the M3 CSL on a number of fundamental points. Just one example is the consistent use on the car of carbon-fiber reinforced plastic, the material in Formula 1 racing.  Looking at the engine, the high-speed concept of BMW M’s well-known M3 straight-six again underlines the role of lightweight engineering in engine construction. Thoroughly modified, the upgraded engine comes with a streamlined cylinder charge process and friction reduced to a minimum, boosting output in the process with more than 350 bhp. And to shift gears within fractions of a second, ensuring a direct flow of power at all times, the car naturally features BMW’s Sequential M Gearbox with Drivelogic (SMG), again based directly on Formula 1 technology. Featuring electrohydraulic, microprocessor-controlled clutch operation, this highly advanced transmission is masterminded by two paddles directly on the steering wheel. Through its overall concept and harmony of features, this lightweight sports car is designed and built for dynamic motoring of the highest standard.  Lightweight engineering is nevertheless not a purpose in itself by the making of the M3 CSL of BMW M. Rather, the absolute weight and the mass inertia of a car around its vertical axis are crucial to the car’s lateral, vertical and longitudinal dynamics – that is how the driver experiences the dynamic behavior of his car. Just for comparison, the series-production BMW M3 weighs 1,495 kg or 3,296 lb unladen, while the M3 CSL Concept Car is about 200 kilos (440 lb) lighter. Precisely this is the crucial factor, the power-to-weight ratio being essential for optimum longitudinal dynamics, that is fast acceleration. And here the improvement is even more significant, the series-production M3 coming with a power-to-weight ratio of 4.36 kg/bhp (9.6 lb/bhp) versus less than 3.5 kg/bhp (7.7 lb/bhp) of the M3 CSL Concept Car.

Dynamic driving test of the toughest caliber on the northern circuit of Nürburgring.

There is no better place in the world to test all these dynamic performance criteria as thoroughly and quickly as the northern circuit of Nürburgring, the most demanding racetrack in the world. This is where the great stand out from the good and the good beat the bad in terms of their driving dynamics, with the total lap time obviously depending on the interplay of all components within the car. Covering the northern circuit in well under eight minutes, the M3 CSL Concept Car beats its production counterpart by almost 30 seconds. The lightweight concept comes out clearly in the M3 CSL Concept Car in many respects and on many features: The flaps in the front air dam, exterior mirror housing and the roof are visibly made of carbon-fiber. The front air dam itself as well as the doors are made of carbon-fiber finished in body color, as are the rear lid optimized for perfect streamlining with its higher rear spoiler and the rear-end diffuser. A solid sandwich panel takes the place of the through-loading bulkhead between the passenger compartment and the luggage compartment, and the two racing-style bucket seats for the driver and front passenger as well as the door linings, the center console and instrument trim are also made of carbon-fiber reinforced plastic.

Carbon-fiber is however not the only alternative: The body-in-white is pressed out of high-strength steel panels, the rear window is made of extra-thin glass, the floorpan is in sandwich structure. The floor panel in the luggage compartment, in turn, is a honeycomb sandwich plate normally to be found only in aerospace applications, the substrate beneath the instrument panel is made of magnesium. Even the bottom layer beneath the carpet on the floor comes in weight-optimized foam. The M3 CSL Concept Car rests on 19-inch wheels incorporating 18-inch lightweight brakes for supreme stopping power.  Lightweight engineering need not necessarily mean spartan motoring: With the exception of side airbags, the toolbox and the rear seats replaced by storage boxes, the driver and his passenger do not have to forego any of the usual amenities. At least in theory, because the M3 CSL Concept Car is a unique, one-off model not for sale.