Intelligent lightweight design was a top priority in the development of the BMW M3 and BMW M4. The goal was to minimise kerb weight in order to give both models outstanding driving dynamics and exemplary efficiency. The kerb weight of the BMW M4 has been reduced to less than 1,500 kilograms, which means the new model is now around 80 kilograms lighter than a comparably equipped predecessor model.
On the outgoing models, the CFRP roof was confined to the Coupe version. Now, for the first time, the four-door BMW M3 will also include this feature. The CFRP roof brings weight savings of five kilograms in the case of the BMW M3 Sedan and more than six in the case of the BMW M4 Coupe. It also lowers the vehicle’s centre of gravity, which has a positive impact on driving dynamics.
The new BMW M3 Sedan and new BMW M4 Coupe also feature a CFRP propeller shaft. CFRP’s high rigidity and low weight mean that the drive shaft can be produced as a single-piece component without a centre bearing. This provides 40 per cent weight savings over the previous model, and the reduction in rotating masses results in sharper throttle response.
Aerodynamics are one of the key elements of the M model. 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 given the significant loads they are operating under. But at the same time, the cars should also have a good Cd – an indicator of impressive efficiency at higher speeds, in particular.
Details such as the powerfully formed front apron, smooth underbody and clearly defined Gurney spoiler lip at the rear of the M3 Sedan (or integrated spoiler lip at the rear of the BMW M4 Coupe) reduce lift by an equal degree at the front and rear axle and produce optimum handling attributes. 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.
Elements like the Air Curtain and M gills with integrated Air Breather rearwards of the front wheels minimise turbulence in the front wheel arches. And, together with the smoothly sculpted exterior mirrors, they are also highly distinctive design features of the BMW M3 Sedan and BMW M4 Coupe.