On the basis of our experience working with the Kawasaki factory racing team, we have developed complete Akrapovic RACING and EVOLUTION exhaust systems for the ZX 6 R. You too will be the happy recipient of a few extra horsepower. Power: More power at the top of the rpm range is the identifying characteristic of the Akrapovic Racing and Evolution exhaust systems, and this Kawasaki is no exception. The boost in power begins only at 9000 rpm and runs into the overrev range. 111.8 HP at 12950 rpm is the measured max. horsepower on the rear wheel, i.e. 4.1 HP more than the stock system, but that?s not the maximum increase, which is a further 1 HP. Up to 9000 rpm there is no great difference in power using the Akrapovic system. Torque: The racing nature of the Akrapovic exhaust systems for the Kawasaki ZX 6R 636 is also reflected in the torque curve. Once again the increase is only apparent from 9000 rpm onwards, where together with the power curve it follows the commands of the rider.