December 18, 2013

Frits Overmars Expansion Chamber aka FOS exhaust concept

Frits Overmars is a well known tuner and very knowledgeable on Aprilia 2T racing bikes. The below schematic with calculations, offers his point of view with a simplified exhaust concept that will give some basic exhaust dimensions to start working on.


  1. I beleive this design was made by Frits Overmars himself.