ECS Tuning B8 / B8.5 Audi A4 Quattro High Flow Catted Downpipe
ECS Tuning B8 / B8.5 Audi A4 Quattro High Flow Catted Downpipe
ECS Tuning B8 / B8.5 Audi A4 Quattro High Flow Catted Downpipe
ECS Tuning B8 / B8.5 Audi A4 Quattro High Flow Catted Downpipe

ECS Tuning B8 / B8.5 Audi A4 Quattro High Flow Catted Downpipe

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The perfect way to unleash hidden horsepower in a modern turbocharged engine is to upgrade the restrictive factory catalytic converter and resonator 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 larger internal diameter and a less-restrictive 200 cell catalytic converter. We measured maximum gains of +27 WHP and +46 ft/lbs of torque on our Audi B8 A4 when equipped with APR Stage 2 ECU software and ECS Luft-Technik Intake, FMIC and Charge Pipes, when flashed from Stage 1 to Stage 2 software and bolting on our downpipe with high flow cat.

Through multiple design iterations and stringent product testing, we have engineered our High Flow Catalytic Converter and Downpipe to not only free up horsepower, but to provide trouble-free installation.  Designed and engineered in house, our High Flow Catalytic Converter and Downpipe utilize only premium materials and manufacturing techniques to deliver unmatched quality and reliability. Made of exquisite brushed T304 stainless steel and precision ground extra-thick CNC-Cut T304 stainless steel flanges, it is sure to look great and hold up to whatever is thrown at it.  New gaskets, 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 bungs are TIG welded in the OE-locations so no extension harness is needed.  The downpipe features a stainless steel flex section that provides proper range of motion and heat expansion. The downpipe mounting point features an OEM styled mount for a direct fit to the stock mounting position to prevent disconnection.  A 1.6mm wall thickness was chosen for reduced cabin noise and increased life span of the product.

To complete our downpipe, we've included an expanded reducer with exhaust clamps that reduces to the OEM exhaust size. Please note that our downpipe ends at the factory clamping location and is 3.0" OD at this connection point. If using an aftermarket cat-back system some modifications or additional components may be needed. 

Our ECS Tuning High Flow Cat and Downpipe offer 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 the factory stock tune.
  • This product is in intended for off-road use only. Not intended for states our counties where regulations prohibit its use.

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