Catalyst / Bypass
The Catalysts Premium range of DPFs is made using silicon carbide as opposed to cordierite which is used in the standard range of DPFs. Also known as carborundum, it is a material widely used in applications that require a high thermal or strength endurance.

Fits:
Porsche 957 Cayenne 3.0 DIESEL Tiptronic S 1/2009-02/2010
M059D engine (Euro 4 DPF only)
Length*: 680mm
Weight: 6kg
* Lengths are measured flange to flange in a straight line (shortest distance) and should only be used as a guide
Warranty: 3 years manufacturer's warranty
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
955113023GX
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06
- Porsche 957 Cayenne 3.0L Diesel 2007-10
This is standard replacement secondary Catalytic Converter made out of cordierite.

Fits:
Porsche 957 Cayenne 3.0 DIESEL Tiptronic S 1/2009-02/2010
M059D engine (Euro 4 DPF only)
Length*: 680mm
Weight: 4.6kg
* Lengths are measured flange to flange in a straight line (shortest distance) and should only be used as a guide
Warranty: 2 years manufacturer's warranty
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
955113023GX
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06
- Porsche 957 Cayenne 3.0L Diesel 2007-10

Replaces the restrictive factory catalytic converters with much less restrictive straight-through pipes for maximum flow and performance.
Cayenne S models have 4 catalytic converters.
The 2nd set is only to make to car extremely quiet - unnecessarily quiet. Catalytic converters are great small easily placed mufflers.
FEATURES:
• Fits: all Porsche 955 Cayenne S vehicles (2002-2007)
• Adds 15 wheel horsepower increasing throttle response
• Saves 24 lbs from the vehicle versus bulky Catalytic Converters
• Fabspeed's Secondary Cat bypass Pipes replace the restrictive factory catalytic converters with much less restrictive straight-through pipes for maximum flow and performance.
• Direct bolt-on replacement for the heavy factory catalytic converters
• Adds an aggressive exhaust note for exotic high-performance sound
• Constructed from polished T304L stainless steel
• All Fabspeed performance products are backed by the Fabspeed Lifetime Limited Warranty.
Please note: These sport cats will make your car sound louder than with stock cats. If you have ,or intend to install sport silencers, you may find the car is a bit loo loud. We recommend to use one sport exhaust component if you are concerned about decibel levels.
Please note: This is a special-order item manufactured to order. In some cases, please allow 4 – 5 weeks for the delivery. Special order items cannot be cancelled from this supplier once your order has been placed.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
FSPOR955V8CB
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06

Replaces the restrictive factory catalytic converters with much less restrictive straight-through pipes for maximum flow and performance.
FEATURES:
• Fits: all Porsche 955 Cayenne Turbo / Turbo S vehicles (2002-2007)
• Increases horsepower and torque by 27 whp and 22 ft-lbs
• Saves 24 lbs from the vehicle versus bulky and restrictive factory catalytic converters
• Fabspeed's Secondary Catbypass Pipes replace the restrictive factory catalytic converters with much less restrictive straight-through pipes for maximum flow and performance.
• Direct bolt-on replacement for the heavy factory catalytic converters
• Adds an aggressive exhaust note for exotic high-performance sound
• Constructed from polished T304L stainless steel
• All Fabspeed performance products are backed by the Fabspeed Lifetime Limited Warranty.
Please note: These sport cats will make your car sound louder than with stock cats. If you have ,or intend to install sport silencers, you may find the car is a bit loo loud. We recommend to use one sport exhaust component if you are concerned about decibel levels.
Please note: This is a special-order item manufactured to order. In some cases, please allow 4 – 5 weeks for the delivery. Special order items cannot be cancelled from this supplier once your order has been placed.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
FSPOR955TCB
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne Turbo 4.5L 2003-06
- Porsche 955 Cayenne Turbo S 4.5L 2006>>

Porsche Cayenne (955) Turbo 2002-2006
RACETRACK USE ONLY
These components are designed and developed for racetrack use and to maximise the car's performance. They are not street legal and must be installed by professionals in the sector.
The component is perfectly interchangeable with the original components, following the instructions in the constructor's workshop manual.
CATALYTIC CONVERTER REMOVAL
Complete removal of the catalytic converter minimises exhaust back pressure and delivers optimum results in terms of performance and weight reduction.
ECU REMAPPING
ENGINE LIGHT
Replacement or removal of components such as catalytic converters, GPFs and electric actuators may cause the engine warning light to come on. In this case, the installer must reprogram the software to eliminate the light.
MATERIAL
AISI 304 STAINLESS STEEL
A choice stainless steel ideal for aggressive environments where combustion emissions can cause serious chemical corrosion on other types of metal.
MAIN PIPE DIMENSION - 65mm
This is the diameter of the main pipe of the exhaust system.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
04090571307
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne Turbo 4.5L 2003-06
- Porsche 955 Cayenne Turbo S 4.5L 2006>>

Fits:
Porsche 955 3.2i V6 8/03-4/07 (2nd cat)
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
95511302411
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne 3.2L V6 2003-06
These are standard replacement secondary Catalytic Converters

Fits:
Porsche 955 S 4.5L M48.00 Engine
Our cat is made up of the following components:
- Ceramic monolith of a honeycomb design to allow free air flow and maximum surface area, coated with precious metals to enable the conversion of gasses that pass through it
- Interam matting to hold the monolith in place. The matting expands when exposed to heat to supply the pressure needed to keep the monolith secure
- A grade 409 stainless steel can (or housing) to provide protection and enable the cat to be built into the exhaust system. 409 grade can contain upto 90% iron and will be prone to rust. It still has higher rust-resistant properties than mild steel.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
95511302
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06

Fabspeed's Sport Cats include a high performance stainless steel flex bellow section for optimal fit.
Direct replacement for factory OEM catalytic converter; Fabspeed's Sport Cats are lighter, higher flowing, and more durable for increased performance and longevity.
FEATURES:
• Fits: all Porsche 955 Cayenne Turbo / Turbo S vehicles (2002-2007)
• Adds 15 whp for noticably improved throttle response
• Saves 18 lbs versus the factory bulky catayltic converters
• Includes 200-cell HJS Sportcats imported from Germany for maximum flow
• Constructed from high-quality 14-16 gauge C.N.C. mandrel-bent T304L stainless steel for optimum flow and maximum durability
• Direct replacement for factory catalytic converters
• All Fabspeed performance products are backed by the Fabspeed Lifetime Limited Warranty
Please note: This is a special-order item manufactured to order. In some cases, please allow 4 – 5 weeks for the delivery. Special order items cannot be cancelled from this supplier once your order has been placed.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
FSPOR955TPSC
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne Turbo 4.5L 2003-06
- Porsche 955 Cayenne Turbo S 4.5L 2006>>

Increase power and sound with a free-flowing x-pipe section that replaces the restrictive and redundant factory secondary catalytic converters for increased exhaust flow.
FEATURES:
• Fits: all Porsche 955 Cayenne V6 vehicles (2002-2007)
• Adds 10 horsepower for improved throttle response
• Dramatic improvement in exhaust tone and noticeable power gains!
• Direct replacement for restrictive and redundant OEM secondary catalytic converters
• Constructed from 14-16ga CNC mandrel-bent T304L stainless steel
• Simple bolt-on installation
• All Fabspeed performance products are backed by the Fabspeed Lifetime Limited Warranty
Please note: This is a special-order item manufactured to order. In some cases, please allow 4 – 5 weeks for the delivery. Special order items cannot be cancelled from this supplier once your order has been placed.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
FSPOR955V6CB
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne 3.2L V6 2003-06

Porsche Cayenne S (955) 4.5ltr 2002-2006
RACETRACK USE ONLY
These components are designed and developed for racetrack use and to maximise the car's performance. They are not street legal and must be installed by professionals in the sector.
The component is perfectly interchangeable with the original components, following the instructions in the constructor's workshop manual.
CATALYTIC CONVERTER REMOVAL
Complete removal of the catalytic converter minimises exhaust back pressure and delivers optimum results in terms of performance and weight reduction.
ECU REMAPPING
ENGINE LIGHT
Replacement or removal of components such as catalytic converters, GPFs and electric actuators may cause the engine warning light to come on. In this case, the installer must reprogram the software to eliminate the light.
MATERIAL
AISI 304 STAINLESS STEEL
A choice stainless steel ideal for aggressive environments where combustion emissions can cause serious chemical corrosion on other types of metal.
MAIN PIPE DIMENSION - 60mm
This is the diameter of the main pipe of the exhaust system.
NOTE: Sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001 in the United Kingdom. They are not MOT compliant and must not be used on public roads. These components are intended for race and track use only. If you are located outside the UK, please consult your local laws and regulations to ensure compliance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
04090581307
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06
3 needed for each catalyst, Sold individually.

Fits:
Porsche 955 Cayenne S 2003-06
* PR:T91 - Units for engine PR no. D9K
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
N10444501
The product you are viewing cross references to these numbers
- Porsche 955 Cayenne S 4.5L V8 2003-06
Exhaust Catalytic Converters & Bypass Pipes – Performance, Efficiency & Flow Control
The catalytic converter plays a crucial role in your Porsche’s exhaust system, reducing harmful emissions while maintaining optimal exhaust flow. Positioned between the exhaust manifold and silencer, it converts toxic gases such as carbon monoxide, hydrocarbons, and nitrogen oxides into less harmful emissions before they exit the tailpipe.
At Design911, we offer a complete range of catalytic converters and bypass pipes for Porsche vehicles. Our manufacturer-quality converters ensure reliable emission control and long-term performance, while our bypass options are designed for track or performance use, optimising exhaust flow for maximum power and throttle response.
Whether you’re maintaining your Porsche to meet emissions standards or upgrading for improved exhaust performance, our selection includes both direct-fit converters and performance bypass kits built from high-grade stainless steel for strength, corrosion resistance, and durability.
What Do Catalytic Converters & Bypass Pipes Do?
A catalytic converter uses a fine mesh of precious metals to trigger chemical reactions that break down pollutants. The bypass alternative eliminates restriction in the exhaust flow, improving performance in non-emissions-controlled environments such as track driving.
Core Functions:
- Converts
toxic exhaust gases into environmentally friendly emissions.
- Maintains
exhaust back pressure for engine efficiency.
- Reduces harmful NOx, CO, and HC emissions.
- Supports smoother engine performance and throttle control.
- Bypass versions enhance exhaust flow and improve power output for track cars.
Upgrading to a performance-grade system ensures your Porsche continues to meet emission requirements — or achieves greater flow and responsiveness for motorsport applications.
Why Do Catalytic Converters Fail?
Catalytic converters are exposed to extreme heat, unburnt fuel, and contaminants — all of which can degrade their performance over time.
Common Causes of Failure Include:
- Carbon
or oil buildup blocking the internal honeycomb.
- Thermal
damage from overheating or rich fuel mixtures.
- Physical
damage from road debris or misfiring engines.
- Corrosion
due to moisture and exhaust condensation.
- Age-related wear reducing catalytic efficiency.
A failing converter can cause reduced engine power, poor
fuel economy, rattling sounds, or a check-engine light. Replacing it
restores emissions compliance, performance, and exhaust efficiency.
Why Replace or Upgrade
with Precision-Engineered Components?
Replacing a failing converter or upgrading to a bypass pipe ensures your Porsche maintains peak performance and reliability.
Key Benefits:
- Restores optimal emissions performance and efficiency.
- Improves exhaust flow and throttle response.
- Reduces engine stress and fuel consumption.
- Durable stainless-steel construction for longevity.
- Direct-fit
compatibility for Porsche 911, Cayman, Boxster, Panamera, Macan
and more.
- Performance bypass options available for track and tuning applications.
Whether you want emissions compliance or maximum flow for competition use, our parts deliver reliability, precision, and performance.
Highlights:
- Direct-fit catalytic converters and bypass pipes for Porsche models.
- Precision-engineered for optimal flow and reduced emissions.
- Built from heat-resistant stainless steel for durability.
- Bypass pipes for performance tuning and track applications.
- Restores power, efficiency, and exhaust sound balance.
- Available for classic and modern Porsche vehicles.