Measurement of the effect on brake performance of the intake and exhaust system components in a motorbike high speed racing engine

The paper presents a series of brake performance measurements for a high speed Road Racing Supersport motorbike engine. A modular approach consisting in a progressive assembling of each component belonging to the intake and exhaust systems is used to investigate the influence of these components on volumetric efficiency through brake torque chassis dynamometer tests. In spite of the design effort that is usually made to keep the cylinder air intake independent of each other in this kind of engines, results showed a considerable acoustic coupling between the intake primary manifolds and the upstream components. Moreover, a good correspondence is found about intake and exhaust tuning regimes between experimental results and analytical relationships proposed in the literature. The presented results can also be interpreted as representative for the overall very high speed engines category (including MotoGP and F1 ones), being the air-breathing system layout mostly independent of engine technological level within this category.