Design of Exhaust Systems for V-Twin Motorcycle Engines to Meet Silencing and Performance Criteria
This paper reports on the use of mathematical modelling by the GPB method of pressure wave propagation through finite systems, for the design of prototype exhaust systems and silencers for a Harley-Davidson motorcycle. The motorcycle engine is the classic 1340 cm3 45° V-twin power unit. The design objectives were to gain mid-range power and torque without loss of performance at either end of the speed range and to design silencers which would enhance the performance and the noise image of the machine. The Queen's University of Belfast (QUB) (3)* employed their unsteady gas flow modelling techniques to the design of the system and its silencers to complement a new camshaft design from Crane Cams. The results of the use of these computer based design techniques are reported as performance characteristics of power and torque for the new design by comparison with the stock system.