Free Flow Exhaust Question


I have a 2019 Yamaha GP1800R. The ski is currently at a local PWC shop for installation of the RIVA Stage 1 Plus Kit. The owner of the shop has a 2018 GP1800 with the RIVA Stage 1 Plus Kit. He showed me he had just bought the RIVA Free Flow Exhaust system for his ski.

My question is what are the reasons to buy the Free Flow Exhaust system with or without the RIVA Waterbox? I know PWC Muscle just uploaded a video saying a customer wanted more noise and the installation does look cool. Does the installation have performance results also?



You’ll get slightly less back pressure, and Riva does advertise up to 15hp increase with their waterbox. That’s on a highly modified ski though. Unless you’re running high-than-stock boost levels and RPMs, you won’t likely get any performance increase from the waterbox. It does add a LOT of additional decibels to the sound though.