Akrapovic Racing and Evolution Exhaust Systems Yamaha YZF-R1 2009-2013 Akrapovic Racing and Evolution systems are designed for riders who demand maximum performance from their motorcycle. Both systems are significantly lighter if compared to stock exhaust system and feature exceptional production quality, hi-tech materials and of course increased engine performance combined with pure racing sound output. Akrapovic Racing and Evolution systems were developed to complement the racing character of the R1. Evolution systems are made entirely of Akrapovic's exclusive high grade titanium while Racing systems use stainless steel header tubes and link pipe. Akrapovic offers titanium or carbon-fiber mufflers for each combination. Both systems are not EC Type approval and are designed for racing purpose only. Evolution System is made entirely of exclusive high grade titanium Racing System uses stainless steel header tubes and link pipe Power Torque The power increase with the Akrapovic exhaust is substantial, and can be seen from 7000 rpm right to the top of the range. At 12460 rpm we measured 165.7 HP, with max. increased power of 7.8 HP at 5900 rpm. The systems effect on the torque and power curve is huge and strongest in midrange rpm. The main increase starts at around 4500 rpm and continues right into the over-rev range. All this will help you shave lap times and result in much smoother ride. Click here for power figures for this part NOTE Please check local laws before purchasing. Some modifications may be prohibited in some states.