X-haust Noise Reducer
The Hush of Power
FOND DU LAC, Wis., Feb. 14, 2008 – Mercury Racing is pleased to announce the introduction of X-haust, a fully integrated sterndrive exhaust noise reduction system. X-haust was developed primarily to bring the HP600 SCi and
EU662 SCi sterndrive engine packages, already certified by the European Union (EU) Recreational Craft Directive (RCD) requirements for exhaust emissions, in compliance with the stringent RCD noise regulations.
The EU RCD consists of strict exhaust emissions and noise regulations for both two-stroke and four-stroke recreational marine engines. Regulations for compression ignition and four-stroke spark ignition engines were initiated on Jan. 1, 2006. OEM (original equipment manufacturers) boat builders must certify that their boats conform to the RCD noise requirements. X-haust just made that much easier for boat builders doing business in the EU.
The X-haust Noise Reducer system recently passed the stringent EU RCD noise emission standard in a twin engine EU662 SCi-equipped boat. The standard used for the exhaust noise test is ISO 14509. The test requires the boat to pass by the sound meter at a distance of 25 meters (82 feet). The boat must be traveling at least 70 kilometers per hour (43.5 mph) or maximum speed. To pass the test the average of the two highest results must not exceed 78 dB(A). As a point of reference - the sound of water lapping the shore is 75-80 dBA.
Mercury Racing employed predictive simulation in the X-haust design. This allowed the engineers to model characteristics of the engine and predict the pressure waves that the engine creates through the exhaust system. After adopting a basic design idea, several iterations were applied until the muffler was perfectly sized and the required sound attenuation was achieved.
The patent-pending muffler design flows exhaust through two separate chambers connected by three attenuator tubes before exiting the exhaust outlet at the bottom. The result is a further reduction of sound pressure waves without sacrificing engine power or performance.
X-haust features a custom Y-Pipe which combines the two banks of exhaust from each engine into a single exhaust tube. The single tube exhaust outlet per engine provides the transom space needed for the transom-mounted X-haust muffler. Back pressure is minimal, resulting in insignificant power loss.
An integrated idle relief tube routes some exhaust through the boat above the waterline, providing a necessary vacuum break and a little rumble when operating off plane.
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.
Mercury Racing’s EU662 SCi is the only high-performance marine engine to meet both EU RCD exhaust emission and noise emission requirements for gasoline sterndrive engines. The EU662 SCi is also the highest horsepower marine engine certified for sale in the EU.
X-haust is available in two configurations. Stage 1, designed to satisfy most noise regulations outside of the EU, eliminates the transom-mounted mufflers. The exhaust outlet remains in the same location - underwater when off-plane and near the water surface when operating on-plane. Stage 2 is the complete system, with transom-mounted mufflers, capable of compliance with the EU RCD.
X-haust is available for use with the HP600 SCi, fitted with an Integrated Transom System (ITS) Bravo One XR drive model or optional dry-sump NXT1 drive, and with the EU662 SCi and HP700 SCi sterndrive engine packages fitted with the dry-sump NXT1 drive. Stage 1 and Stage 2 configurations are available for single- or twin-engine applications in both side-by-side and staggered installations.
About Mercury Racing
Based in Fond du Lac, Wis., Mercury Racing, a division of Mercury Marine, is a leading provider of high-performance marine propulsion systems to discriminating boaters worldwide, offering an exciting and fulfilling powerboating experience on the water.
Using leading-edge technology, Mercury Racing produces high-performance outboards, sterndrives, propellers, parts and accessories.
Mercury Racing-powered boats worldwide win more races and set more records than any boats powered by other marine engine manufacturers.
Mercury Marine is the world’s leading manufacturer of recreational marine propulsion engines. A $2.3 billion division of Brunswick Corporation (NYSE: BC), Mercury and its 6,200 employees worldwide provide engines, boats, services and parts for recreational, commercial and government marine applications. Mercury’s industry-leading brand portfolio includes Mercury and Mariner outboard engines; Mercury MerCruiser sterndrives and inboard engines; MotorGuide trolling motors; Mercury and Teignbridge propellers; MotoTron electronic controls; Mercury inflatable boats; Mercury SmartCraft electronics; and Mercury and Quicksilver parts and oils. Mercury Marine’s OptiMax engine was ranked "Highest in Customer Satisfaction with Two-Stroke Outboard Engines Two Years in a Row, Tied in 2007" by J.D. Power and Associates, and Mercury MerCruiser engines were ranked "Highest in Customer Satisfaction with Sterndrive Engines, Two Years in a Row." More information is available at www.mercurymarine.com.
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