Audi B9 S4/S5 Cast Stainless Steel High Flow Catted Downpipe

  • $816.95
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Product Details

The perfect way to unleash hidden horsepower in a modern turbocharged engine is to upgrade the restrictive factory catalytic converter with a smoother, higher flowing unit. This is a great way to increase performance and add a nice growl to the exhaust note. Ideal performance is achieved through expelling exhaust gasses at maximum velocity through a less-restrictive catalytic converter. We measured maximum gains of +34WHP and +41ft/lbs of torque on our Audi B9 S4 with a stock tune when equipped with an ECS Kohlefaser Luft-Technik Intake System, ECS X-Pipe, and ECS Intercooler/Charge Pipe Kit. 

Through multiple design iterations and stringent product testing, we have engineered our Cast Stainless Steel High Flow Catalytic Converter/Downpipe to not only free up horsepower, but to provide trouble-free installation.  Designed and engineered in house, our Cast High Flow Catalytic Converter utilizes only premium materials and manufacturing techniques to deliver unmatched quality and reliability. Made of exquisite brushed T304 stainless steel piping, cast stainless steel housing, and precision ground 3/8" thick CNC-Cut T304 stainless steel flanges, it is sure to look great and hold up to whatever is thrown at it.  New OE gaskets, class 10.9 bolts, and copper flanged lock nuts are included for a trouble free install.  Each weld joint is hand TIG welded for precision and strength and eye-catching beauty.  The stainless steel oxygen sensor bung is TIG welded in the OE-location so no extension harness is needed. 

Our ECS Tuning High Flow Cat offers impressive real world results.  Get yours today and experience the difference!


  • Aftermarket ECU software is recommended to maximize performance gains as advertised.
  • This product will cause a MIL (Malfunction Indicator Lamp) on factory stock tune.
  • This product is in intended for off-road use only. Not intended for states our counties where regulations prohibit its use.