The sportiest and most powerful motorcycle from BMW, the new S 1000 RR, draws its combustion air from an intake system with a built-in air filter function made from Ultramid B3WGM24 HP, an extremely dimensionally stable polyamide (PA) from BASF. In motorcycle design, this component is called an airbox. For this high-performance motorcycle, the Stuttgart and Öhringen facilities of MAHLE (Germany) developed and manufactured the first airbox with an electrically adjustable runner length. It combines high performance with light weight.
The air box consists of an upper and a lower part that are welded together. The actuator for varying the runner length is attached to the lower part prior to welding. "Since the dimensional accuracy of the housing components affects the exactness of intake pipe adjustment, absence of distortion in the plastic parts is a major concern", explained Nicole Berg, production planner at MAHLE. The welding characteristics of the material are also very important, since the limited space available requires very small welding geometries. In addition, the mineral content of the resin helps to reduce noise considerably.
From automobile to motorcycle
Now that the polyamide air intake manifold has become fairly commonplace in the European automobile industry, the field of application for this plastic component is expanding into the motorcycle sector. Compared to the automobile intake manifold, special aspects of the motorcycle application include the short intake pipe lengths and the limited space available for installation. With its active length adjustment, the new intake system permits the BMW S 1000 RR to optimize the torque curve over a wide range.