Our new 520 sterndrive has been a resounding success since it was introduced one year ago at the LOTO (Lake of the Ozarks) Shootout. It’s become even more popular since the release of a Joystick Piloting for Sterndrives – Axius option for selected models fitted with the Bravo Three XR sterndrive. Formula boats have been early adopters of the engine package. They are also the first OEM boat builder to install the potent engines with joystick control. A Formula 400FX used to demonstrate joystick 520 maneuvers at the Miami Boat Show had standard through transom exhaust fitted with aftermarket mufflers. For our traditional sport boat crowd – they had a nice exhaust note. For those looking for enhanced performance without all the rumble – it might have been a bit much.
We took note, no pun intended, and went to work to create an X-haust Noise Reduction system designed specifically for the 520. The system will appease our friends at Formula and a variety of our OEM boat builder partners, dealers and consumers looking to take advantage of the 520’s performance value. It will also be adopted in European Union countries where the engine is certified in meeting the stringent RCD (Recreational Craft Directive) exhaust emissions standards.
The 520 X-haust Noise Reducer system may be used for single and twin engine applications in which the engines are installed close-coupled to the transom. Drive-line installation options are not available at this time. The 520 kit is configured similarly to kits used with our supercharged sterndrive engine packages (600 SCi, 662 SCi and 700 SCi). A custom y-pipe combines the two banks of exhaust from each engine into a single exhaust tube that exits the transom below the water line. An integrated idle relief tube routes some exhaust through the boat, above the waterline, providing a necessary vacuum break. This is referred to as “Stage 1” X-haust. This configuration is sufficient to meet most noise regulations outside of the EU.
Stage 2: To meet the stringent EU RCD noise emissions requirements (maximum 78 dBA), Mercury Racing engineers designed a transom mounted muffler which is perfectly sized to achieve the required sound attenuation. The muffler design, connected to the Stage 1 X-haust transom outlet, flows exhaust through two separate chambers connected by three attenuator tubes before exiting the exhaust outlet at the bottom. The result is further reduction of sound pressure waves without sacrificing power or performance. The transom mounted muffler is completely submerged when the boat is at rest. The muffler outlet directs engine exhaust down and back toward the transom, further reducing noise. We call this complete system, with mufflers, Stage 2 X-haust. The 520 X-haust Noise Reducer System may be used with a variety of Bravo One XR and Bravo Three XR drive options fitted with standard transom plates or the optional Integrated Transom System (ITS).
520 X-haust Noise Reducer System Part Numbers:
Contact our sales department by calling toll free at 866-637-2234 for 520 X-haust Noise Reducer pricing and availability. I’m looking forward to seeing the various applications of the global, magical and now quiet 520 sterndrive!
