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Design 911 Design 911 supply Porsche parts, Porsche spares and Porsche accessories, to both retail and to the trade. Our Porsche product and accessory range includes brakes, exhausts, tyres, wheels and Porsche panels and interiors. https://design91.uk/images/schemaLogo.png https://design91.uk/images/schemaLogo.png +443456003478 https://design91.uk Facebook Instagram

Catalyst / Bypass

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DISPLAYING 1 to 8 (of 8 products)
3606109876
Product Information
Product Information
A Voucher for £100 available when you buy this product. For more information CLICK HERE

DesignTek Exhaust manifold / header with catalyst bypass.
Price is for PAIR.

designtek

Fits:
Porsche 987.2 Boxster 2.9L / 3.4L 2009-12
Porsche 987C.2 Cayman 2.9L / 3.4L 2009-12

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Related, superseded, cross reference or alternative numbers for comparison.

3606109876
3606109875
98711310133
987113101AX
98711310233
987113102AX

The product you are viewing cross references to these numbers
9M81113211
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Product Information
9m Equal length exhaust manifold with catalytic converter. 
Sold as a pair - left and right

Fits:
Porsche 981 Boxster - 2012 to 2016
Porsche 981 Boxster S - 2012 to 2016

Porsche 981 Boxster GTS -  2012 to 2016
Porsche 981 Boxster Spyder - 2016
Porsche 981 Cayman - 2013 to 2016
Porsche 981 Cayman S - 2013 to 2016
Porsche 981 Cayman GTS - 2013 to 2016
Porsche 981 Cayman GT4 - 2016

Made from SS304L lightweight stainless steel these exhaust manifolds offer reduced back pressure with higher flow

  • Performance gains of 20hp minimum and 20nm
  • Improved throttle response
  • Improved exhaust note with no drone, resonation or vibration
  • Direct fit no remap required but recommended
  • No CEL
  • Heat shielded to reduce radiant heat and speeds up exhaust gas velocity



Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

9M81113211
98111321101
98111321102
98111321103
98111321104
98111321105
981113211EX
98111321106
981113211FX
98111321201
98111321202
98111321203
98111321204
98111321205
981113212EX
98111321206
981113212FX

The product you are viewing cross references to these numbers
9M87113101
Product Information
Product Information
Equal length exhaust manifold with catalytic converter. 

Fits:
Porsche 987.2 Boxster / Boxster S - 2009 to 2012
Porsche 987.2 Boxster Spyder - 2009 to 2012
Porsche 987.2 Cayman / Cayman S  - 2009 to 2012
Porsche 987.2 Cayman R - 2009 to 2012

987.2 Equal length exhaust manifold with catalytic converter.

  • Reduced back pressure with higher flow
  • Made from SS304L lightweight stainless steel
  • Performance gains of 15hp minimum and 20nm
  • Improved throttle response
  • Improved exhaust note with no drone, resonation or vibration
  • Direct fit no remap required but recommended
  • No CEL (Check Engine Light)
  • Heatshieded to reduce radiant heat and speeds up exhaust gas velocity




Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

9M87113101
98711310133
987113101AX
98711310233
987113102AX

The product you are viewing cross references to these numbers
3606109874
Product Information
Product Information
Exhaust Manifold / Header

designtek

Fits:
Porsche 987 Boxster 2005- 08/2008
Porsche 987C Cayman 2006- 08/2008

DesignTek sports headers and 200 cell high flow cats for throaty sports car sound, but not too loud for every day driving, manufactured from extra heavy duty stainless steel, which eliminates the splitting, cracking and annoying resonance.

Coating: 40g
Cells: 200cpsi

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.

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.

3606109874
3606109874
98711310407
98711310408
98711310410
987113104AX
98711310805
987113108AX
98711310605
98711310606
987113106AX
98711310307
98711310310
987113103AX
98711310705
987113107AX
98711310505
98711310506
987113105AX

The product you are viewing cross references to these numbers
3606109875
Product Information
Product Information
Exhaust Manifold / Header with Cat Bypass

Fits:
Porsche 987 Boxster 2005- 08/2008
Porsche 987C Cayman 2006- 08/2008

Please note: This is a set of headers with catalyst bypass. After the installation of this product the emission light might come on your dash. To remove it you might need to install the lambda sensor extensions.

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.

Please note:
On the video below customer has fitted our headers and sport silencer with secondary cat bypasses. The car on the video has no cats at all!



Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

3606109875
3606109875
98711310407
98711310408
98711310410
987113104AX
98711310805
987113108AX
98711310605
98711310606
987113106AX
98711310307
98711310310
987113103AX
98711310705
987113107AX
98711310505
98711310506
987113105AX

The product you are viewing cross references to these numbers
Special Order item
98711310
Product Information
Product Information
exchange
Reconditioned exhaust manifold with catalytic converter.

Please note:
Reconditioned units are sold on an exchange basis, A surcharge of £1120.80 will be held and then refunded when the old one is returned.

porsche

Fits:
Porsche 987 2.7L Boxster M96.25 Engines
Porsche 987 2.7L Cayman M96.25 Engines

Click 'Zoom in' for large parts diagram.
Diagram ref no 2

Please note:
Reconditioned exhaust manifolds are sold on an exchange basis, A surcharge of £477.00 will be held and then refunded when the old one is returned.



    PLEASE NOTE:
  • The surcharge for this reconditioned part will be refunded when the exchange unit is received and approved by us and the relevant manufacturer.
  • Please note, surcharge refunds often take an average of 6 to 8 weeks to be approved by the manufacturer.
  • Acceptance of the exchange part is at the manufacturer's discretion, based on the part being fit for reconditioning.
  • All surcharges and exchanges are subject to our terms and conditions.




Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

98711310
98711310305
98711310306
987113103AX
98711310405
98711310406
987113104AX

The product you are viewing cross references to these numbers
Special Order item
98711310
Product Information
Product Information
exchange
Exhaust manifold with catalytic converter. Reconditioned unit with deposit charge. Refundable on return of old unit.

porsche

Fits:
Porsche 987 Boxster 2007-08 M97.20 Engines
Porsche 987 Boxster S 2005-08 M97.21 / M97.22 Engines
Porsche 987C Cayman / Cayman S 2006-08 M97.21 / M97.22 Engines

Click 'Zoom in' for large parts diagram.
Diagram ref no 2
100390100392
Product Information
Product Information
Lambda Sensor Blanking Plug and Receiver Socket Set.
In case you need to relocate your existing lambda probe because it's not in the right location. Welding and cutting specialist required.


Fits:
Many Porsche vehicles. Universal kit.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

100390100392
100390
100392

The product you are viewing cross references to these numbers
DISPLAYING 1 to 8 (of 8 products)
Also found on these pages
About Catalyst / Bypass

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.

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