CAP Audi 3.0T Cast V3 Catless Downpipe - B9/B9.5 2018-2025 Audi S4/S5 V3

CAP B9/B9.5 Catless 3.0T Downpipe 

Introducing the long awaited V3 Cast Catless Downpipe from Canadian Auto Performance! The most refined and powerful evolution of our high-flow downpipe lineup for the B9 S4/S5 3.0T platform.

For 2025, we’ve taken everything that made our V1 and V2 downpipes great and raised the bar even higher. This all-new V3 version features a cast stainless steel construction, allowing for smoother flow transitions and enhanced durability.
We also offer a heatshielded variant, which help reduce engine bay temperatures.

Designed for enthusiasts who demand both performance and precision, this downpipe doesn’t just look the part, it delivers results.

It's time to increase your B9 Audi S4/S5's power, by increasing exhaust flow with this Cast downpipe.

Experience increased horsepower, faster turbo response, and a meaner exhaust note. Easy to install and built to last your car's lifetime.

We have to thank Audi for the design of the OEM cat, compared to the B8/B8.5 S4/S5 platform, replacing cats was a total nightmare on those cars. Although professional install is always recommended, the install time of this downpipe generally only takes around the 2 hour mark.

Key Features Of Our 3.0T Downpipe For B9/B9.5 Platform:

• Cast 304 Stainless Steel Construction – Stronger, smoother, and more thermally stable
• Integrated Heatshield – Keeps under-hood temps in check and protects nearby components
• TIG Welded & Back-Purged – Ensures strength and durability where it matters
• Precision-Cut CNC Flanges – OEM-like fitment, no cutting or welding required
• Bolt-On Installation – Includes all necessary hardware, gaskets & bolts
• Enhanced Flow – For increased HP, torque, and turbo response
• Aggressive Exhaust Note – Deep tone without drone on stock exhaust
• Tuned Aesthetic – Clean, robust, and designed to impress at first glance

Important Note: The removal of factory catalytic converters will trigger a check engine light. Software tunes are recommended to maximize the power gains.

Heat Shielded vs. Non-Heat Shielded Downpipes - What to Choose? 

When it comes to choosing between heat shielded and non-heat shielded downpipes for your Audi B9/B9.5 S4/S5, understanding the pros and cons of each option will help you maximize performance and protect your engine components.

Here’s a quick overview to make things easy: 

Benefits of Heat-Shielded Downpipes for your B9/B9.5 Audi S4/S5

Heat shielded downpipes offer several advantages that can significantly improve your Audi's performance and longevity:

1. Reduced Heat Soak: By effectively managing exhaust heat, heat shields prevent excessive temperatures from affecting nearby components, reducing the risk of heat soak and maintaining optimal engine performance.
   

2. Enhanced Engine Bay Protection: Heat shields act as a barrier, protecting sensitive components such as electrical systems, fuel lines, and wiring harnesses from heat-related damage.
   

3. Improved Air Intake Temperature: By keeping engine bay temperatures lower, heat shields help maintain cooler air intake temperatures, leading to better combustion and increased power output.
   

4. Optimized Exhaust Flow: Heat shielding helps maintain higher exhaust gas temperatures, which can improve exhaust flow and scavenging, potentially leading to better turbocharger performance and faster spool times.
   

5. Noise and Vibration Reduction: Heat shields can also help dampen noise and vibrations, contributing to a more refined driving experience.
   

For performance enthusiasts looking to maximize their Audi's potential, the benefits of heat shielded downpipes often outweigh the negligible increase in weight and cost.

Does a Catless Downpipe Damage an Audi 3.0T Engine?

Let’s cut through the myths: A catless downpipe won’t harm your Audi’s 3.0T engine if properly paired with CAP’s intercooler & performance tune. While generic catless setups risk issues like elevated exhaust temps or lean fuel trims, CAP’s 3.0T downpipes are precision-built to enhance reliability.

Our V2 design uses aerospace-grade 304 stainless steel and mandrel-bent piping to reduce back pressure without overheating turbos or stressing engine components.

Key safeguards include:

• Optimized airflow that maintains safe EGTs (exhaust gas temperatures), unlike cheap aftermarket pipes causing thermal runaway.
• OEM+ compatibility with factory sensors and CAP’s O2 spacers (use code SPACER50) to prevent check-engine lights and fuel trim errors.
• Heat-shielded options (available as add-ons) to protect nearby wiring and components from radiant heat.

The real danger lies in failing factory catalytic converters, which fragment and damage turbos – a problem our downpipes eliminate entirely. 

Is a Catless Downpipe Worth It for Your Audi 3.0T?

For Audi 3.0T owners chasing max power and turbo response, CAP’s catless downpipe is the single most impactful bolt-on mod. Here’s why:

Pair it with our 3.0T Intercooler to unlock the full performance potential of your Audi.

Still hesitant? Check our Ultimate Audi Mod Guide for dyno-backed proof why this is the enthusiast’s first mandatory upgrade.

Important Notice:
This product is for Racing Competition only and is not legal for use in highway or street vehicles or other non-racing competition off-road vehicles. By purchasing this product you acknowledge its intended use and represent that you understand and agree that the product is not designed to meet any applicable emissions standards, the product is not C.A.R.B. complaint. Canadian Auto Performance makes no representations, warranties or claims that this product complies with any applicable emissions laws and expressly disclaims any and all such representations, warranties and claims, whether express or implied. By purchasing this product, you represent, warrant and agree that it is your responsibility to inform yourself of any laws or regulations that may apply to your purchase and/or use of the product.