2014 C7 Corvette Fusion Bi-Modal Exhaust System can be simply incorporated with the OEM C7 NPP system controls Proprietary 3" butterfly valve system available (OEM uses 2.5" valves) 3" pipe diameter Manufactured to precise standards using T-304 stainless steel and TIG welding techniques Limited Lifetime Warranty against rust, corrosion or burn through Made in the USA QUICK FACTS Available in 4" round, 4.5" oval double walled tips or Speedway tips We use our experience in bi-modal muffler design to further enhance the factory system. Billy Boat Performance 2014 C7 Corvette Fusion Bi-Modal Exhaust System provides a deeper, richer and more voluminous sound than the OEM NPP system. Mufflers incorporate two passages through which exhaust can travel. A butterfly valve, built into the mufflers, regulates which passage is used. Passage One is a muffled and chambered tube incorporating Billy Boat's exclusive PRT (Purge Resonance Technology) to eliminate drone at cruising speeds, while delivering deep and smooth American V8 muscle car sound. Passage two is a straight through tube that increases the sound volume to adrenaline pumping levels, as well as increases horsepower and torque.