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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://www.design91.uk/images/schemaLogo.png https://www.design91.uk/images/schemaLogo.png +443456003478 https://www.design91.uk Facebook Instagram

Catalyst / Bypass

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DISPLAYING 1 to 7 (of 7 products)
9M96411104205KIT
Product Information
Product Information
Catalytic converter repair flanges and mounting hardware kit


Fits:
Porsche 964 (911) C2 1989-93
Porsche 964 (911) C4 1989-93
Porsche 964 (911) RS 3.6L 1991-93
Porsche 964 (911) RS 3.8L 1991-93

Kit Includes
2 x Catalytic converter / heat exchanger cross over flange
1 x Catalytic converter gasket
1 x Heat exchanger gasket
6 x Heat exchanger to cylinder head seal ring
4 x Heat exchanger barrel nut
16 x Exhaust lock nut
8 x Exhaust bolt M8 x 40

Ninemeister Converter Repair Flange 

Over time, age, heat cycles, and corrosion take their toll on Porsche exhaust systems. A common weak point is the catalytic converter flange, which can corrode and eventually disintegrate. When this happens, it compromises the seal in your exhaust system, leading to exhaust leaks, loss of performance, and increased noise.

The Ninemeister repair flange is a high-quality replacement solution designed specifically to restore your Porsche’s exhaust integrity.

Key Features

  • Direct Repair Solution – allows you to remove the corroded flange and re-weld this precision-machined replacement in place.
  • Durable Construction – built to withstand the extreme heat and corrosive conditions of Porsche exhaust systems.
  • Restores Exhaust Sealing – eliminates leaks, restores back pressure, and ensures smooth engine performance.
  • Cost-Effective Repair – no need to replace the entire catalytic converter when only the flange is damaged.
  • Tailored Fitment – engineered to match Porsche specifications for proper alignment and fit.

Why Replace a Corroded Converter Flange?

  • Eliminate Exhaust Leaks prevent harmful gases from escaping and affecting cabin safety.
  • Restore Performance – exhaust leaks reduce back pressure, causing poor throttle response and reduced efficiency.
  • Prevent Further Damage – corrosion at the flange can spread, leading to costly catalytic converter or exhaust system replacements.
  • Long-Term Reliability – a fresh flange ensures your exhaust remains structurally sound for years to come.

The Ninemeister catalytic converter repair flange provides a reliable, cost-effective fix for corroded catalytic converter flanges, helping you keep your Porsche exhaust system safe, efficient, and true to factory performance.

Section of diagram ref no 1, 3, 4, 5, 6, 7, 8 and 12.



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

9M96411104205KIT
96411104205
96411321310
96411321306
96411321316
96411321317
96421103905
96421103932

The product you are viewing cross references to these numbers
9M96411104205
Product Information
Product Information
Catalytic converter repair flange


Fits:
Porsche 964 (911) C2 1989-93
Porsche 964 (911) C4 1989-93
Porsche 964 (911) RS 3.6L 1991-93
Porsche 964 (911) RS 3.8L 1991-93

Ninemeister Converter Repair Flange 

Over time, age, heat cycles, and corrosion take their toll on Porsche exhaust systems. A common weak point is the catalytic converter flange, which can corrode and eventually disintegrate. When this happens, it compromises the seal in your exhaust system, leading to exhaust leaks, loss of performance, and increased noise.

The Ninemeister repair flange is a high-quality replacement solution designed specifically to restore your Porsche’s exhaust integrity.

Key Features

  • Direct Repair Solution – allows you to remove the corroded flange and re-weld this precision-machined replacement in place.
  • Durable Construction – built to withstand the extreme heat and corrosive conditions of Porsche exhaust systems.
  • Restores Exhaust Sealing – eliminates leaks, restores back pressure, and ensures smooth engine performance.
  • Cost-Effective Repair – no need to replace the entire catalytic converter when only the flange is damaged.
  • Tailored Fitment – engineered to match Porsche specifications for proper alignment and fit.

Why Replace a Corroded Converter Flange?

  • Eliminate Exhaust Leaks prevent harmful gases from escaping and affecting cabin safety.
  • Restore Performance – exhaust leaks reduce back pressure, causing poor throttle response and reduced efficiency.
  • Prevent Further Damage – corrosion at the flange can spread, leading to costly catalytic converter or exhaust system replacements.
  • Long-Term Reliability – a fresh flange ensures your exhaust remains structurally sound for years to come.

The Ninemeister catalytic converter repair flange provides a reliable, cost-effective fix for corroded catalytic converter flanges, helping you keep your Porsche exhaust system safe, efficient, and true to factory performance.

Section of diagram ref no 1






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

9M96411104205
96411104205
96411321310
96411321306
96411321316
96411321317
96421103905
96421103932

The product you are viewing cross references to these numbers
3606209641
Product Information
Product Information
Exhaust Catalytic Converter Bypass Pipes

designtek

DesignTek stainless steel catalyst by-pass produces more air flow which in turn produces more power. Designed to give a deeper more sporter sound.

This product comes with the hole to re-fit the lambda sensor.

Fits:
Porsche 964 C2 / C4 1989-94

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.

Design 911 Recommends this product best value and best quality

NOTE: In the United Kingdom, 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. They are not MOT compliant and cannot be used on public roads. These components are intended solely for race and track use.

For vehicles manufactured before 1st March 2001, a non-type approved sports catalytic converter may be fitted, provided it offers comparable performance to the original and the vehicle continues to meet the applicable emissions standards for its age. The vehicle must still pass an MOT test.

If you are located outside the UK, please check your local laws and regulations to ensure compliance.

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

3606209641
96411321306
96411321310
96411321316
96411321317
96411104205

The product you are viewing cross references to these numbers
3606109641
Product Information
Product Information
Exhaust Catalytic Converter Pipes 100 Cell

designtek

DesignTek stainless steel sports 100 cell catalyst, with German hi-flow catalyst. Produces more air flow which in turn produces more power. Designed to give a deeper more sporter sound.

This product comes with the hole to re-fit the lambda sensor.

Fits:
Porsche 964 C2 / C4 1989-94

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.

Design 911 Recommends this product best value and best quality

NOTE: In the United Kingdom, 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. They are not MOT compliant and cannot be used on public roads. These components are intended solely for race and track use.

For vehicles manufactured before 1st March 2001, a non-type approved sports catalytic converter may be fitted, provided it offers comparable performance to the original and the vehicle continues to meet the applicable emissions standards for its age. The vehicle must still pass an MOT test.

If you are located outside the UK, please check your local laws and regulations to ensure compliance.

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

3606109641
96411321306
96411321310
96411321316
96411321317
96411104205

The product you are viewing cross references to these numbers
1620301400
Product Information
Product Information
Sports Catalytic Converter with catalytic ceramic insert, 100 cell. With Lambda sensor hole and plug. Polished stainless steel.

danskmotorsport

Fits:
Porsche 964 C2 / C4 1990-94

NOTE: In the United Kingdom, 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. They are not MOT compliant and cannot be used on public roads. These components are intended solely for race and track use.

For vehicles manufactured before 1st March 2001, a non-type approved sports catalytic converter may be fitted, provided it offers comparable performance to the original and the vehicle continues to meet the applicable emissions standards for its age. The vehicle must still pass an MOT test.

If you are located outside the UK, please check your local laws and regulations to ensure compliance.

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

1620301400
PO-96260S
PO92260S
1620301400
96411321316
96411321306
96411321310
96411321317
PO-92260S
96411104205
96411104206
96411104217

The product you are viewing cross references to these numbers
96421100391
Product Information
Product Information
Sports Catalytic Converter without catalytic ceramic insert. With Lambda sensor hole and plug. Polished stainless steel. This is a Cat bypass product.


danskmotorsport

Fits:
Porsche 964 C2 / C4 1990-94

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: In the United Kingdom, 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. They are not MOT compliant and cannot be used on public roads. These components are intended solely for race and track use.

For vehicles manufactured before 1st March 2001, a non-type approved sports catalytic converter may be fitted, provided it offers comparable performance to the original and the vehicle continues to meet the applicable emissions standards for its age. The vehicle must still pass an MOT test.

If you are located outside the UK, please check your local laws and regulations to ensure compliance.



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

96421100391
92260S
1620801000
96411104205
96411321306
96411321310
96411321316
96411321317
92.260S

The product you are viewing cross references to these numbers
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 7 (of 7 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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