Home » Exhaust » Downpipes » 034 Stainless Steel Racing Catalyst Downpipe For Audi B9 S4/S5
NOTICE: This is a Race-only product. An electronically signed Race-only Product Acknowledgement Agreement is required prior to shipping out. Instructions will follow after checkout.
Product description

034 Stainless Steel Racing Catalyst Downpipe For Audi B9 S4/S5

The 034Motorsport Stainless Steel Racing Catalyst for B9 Audi S4/S5 is designed as a drop-in replacement for the restrictive factory catalytic converter. The Stainless Steel Racing Catalyst offers increased horsepower and torque throughout the powerband, reduced turbocharger lag, improved throttle response, and enhanced exhaust note. This upgrade eliminates the primary flow limitation in the factory exhaust system, allowing you to maximize the potential of your turbocharged engine.
Optimized for increased flow and maximum performance, the Stainless Steel Racing Catalyst features a massive 148mm diameter Euro 4 racing catalytic converter in the factory location. This complete drop-in solution includes an integrated v-band flange at the turbine outlet, integrated oxygen sensor bung after the catalyst, integrated 3-bolt downpipe flanges, and a complete gasket/hardware kit to allow for precise fitment and ease of installation. The Stainless Steel Racing Catalyst for B9 Audi S4/S5 vehicles is constructed from 304 stainless steel for maximum durability and corrosion resistance, is TIG-welded, and includes an integrated OE style heat isolation barrier  to minimize exhaust heat transferred into the engine bay.
034Motorsport's Stainless Steel Racing Catalyst was developed entirely in-house on 034Motorsport's Development B9 Audi S4 utilizing the latest in 3D Scanning Technology, CAD Software, and Rapid Prototyping Techniques. Final production units were then tested extensively on track in B9 Audi S4 vehicles before release.
  • Increased Horsepower & Torque Throughout the Powerband (+ 21 HP / + 33 TQ Peak)
  • Quicker Turbocharger Spool & Faster Transient Response (150-300 RPM Quicker Spool)
  • Enhanced Exhaust Note & Turbocharger Sounds
  • Direct, Bolt-In Upgrade for Factory Catalytic Converter
  • Engineered In-House by 034Motorsport's Engineering Team
  • Factory-Location 148mm Euro 4 Racing Catalytic Converter
  • 304 Stainless Steel Construction with Integrated Inlet/Outlet Flanges & O2 Sensor Bung
  • Precision CNC-Machined Flange Mating Surfaces
  • OE Style Heat Isolation Barrier
  • TIG Welded & Backpurged
What's Included
  • 034Motorsport Stainless Steel Performance Downpipe
  • Integrated Euro 4 Racing Catalytic Converter
  • Factory Turbocharger Outlet Gasket
  • Factory Catalyst to Downpipe Gaskets (2)
  • M8 Locknuts (6)
  • M8x30 Socket Head Cap Screws (4)
  • M8 Washers (4)
Emissions Disclaimer
  • This product is sold for off-road use only.
  • By purchasing this product, you understand this product is sold for competition use and is not legal for use in highway or street vehicles.
  • This product will cause a check engine light (MIL) on the stock factory tuning. A racing ECU calibration for offroad use only is required to eliminate the check engine light.


  • Audi S4 (B9) 3.0TFSI (2018+)
  • Audi S5 (B9) 3.0TFSI (2018+)

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12.00# 24.00x14.00x8.00

034 Stainless Steel Racing Catalyst Downpipe For Audi B9 S4/S5

Increased Horsepower And Torque Throughout The Powerband

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MFG# 034-105-4045
SKU# 27258

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  • Cars This Fits ...

  • Make Model Year Engine
    Audi S5 B9 (2017+) 3.0T
    Audi S4 B9 (2017+) 3.0T (Quattro)