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Integrated Engineering Performance Cast Downpipe For Audi B9 S4 & S5 3.0T

Integrated Engineering
This is a Race-only product. By adding this product to your shopping cart, you are electronically acknowledging that this product is not to be installed on any registered vehicle that will be driven on any US road, street or highway. In addition, you also acknowledge that the use or installation of this product outside of the intended closed circuit racing purpose may be illegal under the Federal Clean Air Act (42 U.S.C. § 7522(A)(3))

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Track Car Modification Waiver Form

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Engineered as the ultimate downpipe solution for your Audi B9 S4 or S5, every detail is maximized to provide the turbo and engine with a completely unrestricted exhaust flow path for up to 45HP & 41TQ (on hybrid turbo setup). The TIG-welded 304 stainless and investment cast body delivers addictive sound, quality finish, effortless install, reliability, and maximized performance for your turbocharged V6.


  • Required to support hybrid turbo ECU calibrations
  • High-flow design to support full-bolt on stage 2 power capabilities
  • Removes any downpipe restrictions for full available power
  • Increases exhaust sound with improved engine & turbo notes
  • Improves turbocharger efficiency & speeds up turbo spool
  • Thick-wall casting reduces radiant heat in the engine bay
  • 200 CPSI performance high-flow catalytic converter
  • 304 investment cast downpipe body
  • 304 stainless steel downpipe legs & CAT
  • Massive 6" downpipe body to dual 2.5" downpipe legs
  • Hand TIG-welded for superior reliability and surface finish
  • Direct bolt-in factory replacement
  • CNC machined v-band and bolt flanges for leak-free operation
  • Installs to the stock exhaust or IE Midpipes upgrade

*Requires Stage 2 or hybrid turbo ECU tuning

IE's unique thick-wall investment castings produce an aggressive, drone-free exhaust note without the "tinny" sound typical on most full stainless body aftermarket options. Enjoy not only a louder exhaust but one with improved engine and turbo notes that will deliver miles of smiles.

Other aftermarket downpipes use large sections of thin-wall steel tubing to manufacture the downpipe body; this is a cheaper process but can reduce sound quality and sacrifice exhaust flow. Investment casting allows for an optimized design that smoothly transitions exhaust flow from the massive 6" body to the dual 2.5" exhaust legs. The casting also provides a beautiful look that turns the entire downpipe into an attractive gold finish as it wears in from heat cycles over time.

The B9 3.0T hot-v style engine has a unique center-mounted turbo with a large downpipe that quickly splits into twin-sided exhaust sections. This challenging configuration requires exacting alignment to avoid install hassles, rattling, rubbing, and exhaust leaks. IE engineers utilize advanced 3D scanning technology and rapid prototyping to guarantee a flow-maximized design that exceeds even the factory fitment.

IE's downpipe includes a high-flow 200 CPSI catalytic converter. This performance CAT allows for full and unrestricted power from Stage 2 ECU tunes and hybrid turbo upgrades while reducing emissions output and eliminating unwanted smells and bumper stains found on cat-less designs.

The stock downpipe becomes a significant restriction when upgrading to a larger hybrid turbo. IE's cast downpipe is a direct-fit to available upgraded turbochargers on the market and will allow total horsepower, torque, and spool potential from your turbocharger investment.

IE's B9 S4 & S5 intake system, turbo inlet pipe, and downpipe are hybrid optimized, making the installation of popular turbo upgrades an easy bolt-in process.

Real-world power numbers are achieved using our in-house dyno cells to verify the efficiency of the downpipe design. Dyno testing performed in controlled conditions on a hybrid turbo equipped B9 S4 resulted in consistent and significant power gains of 45HP & 41FT-LBS to the wheels!

Install your new downpipe kit without any welding, cutting, permanent modifications, or installation hassles. The process is straightforward with the correct tools.

Click or tap here to download the installation guide


  • 2017+ Audi B9 S4 3.0T
  • 2017+ B9 Audi S5 3.0T

Vehicle fitment is confirmed for the US and Northern America (NA) fitment. Some Rest Of World (ROW) models may have incompatible exhaust systems. Please verify factory part number compatibility with US models before ordering or contact us for support with any fitment questions.

More Information
Brand Integrated Engineering
Stock Type N/A
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