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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 16 (of 18 products)
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L-PO991T/2
Product Information
Product Information
The next step from Akrapovič for the Porsche 911 Turbo / Turbo S is the optional titanium link pipe set without cats, perfectly finished with a coating to offer greater durability without altering the look. Designed to create the best exhaust flow and offering a huge weight saving over stock—when used in conjunction with the Slip-On—the link pipes increase power and give the car a sporty racing sound. Enhancing the tuning opportunities of this superb car, the link pipes without cats are an easy-to-install performance upgrade.

Fits:
Porsche 991 (911) Turbo/Turbo S 2014>>

TECHNICAL DATA
** measured with: Porsche 911 Turbo/Turbo S (991) 2014

Maximum power:
- kW: plus 7.1 / 5400 rpm
- HP (m): plus 9.7 / 5400 rpm
- HP (i): plus 9.6 / 5400 rpm

Maximum torque:
- Nm: plus 50.0 / 2300 rpm
- lb-ft: plus 36.9 / 2300 rpm

Weight:
- minus 5.6 kg / 12.4 lb

Please note: When installing Akrapovič aftermarket optional link pipes without catalytic converters, which are developed for use on closed tracks only, remapping the ECU is mandatory. Akrapovic Delete-R will not eliminate possible engine check errors codes caused by increasing emissions flow.

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Related, superseded, cross reference or alternative numbers for comparison.

L-PO991T
99711300930
997113009AX
99711301030
997113010AX

The product you are viewing cross references to these numbers
3606109915
Product Information
Product Information
A Voucher for £100 available when you buy this product. For more information CLICK HERE

DesignTek Exhaust manifold / header with 200 Cell Euro 4 coating substrate.
Price is for PAIR.

designtek

Fits:
Porsche 991.1 Carrera / S

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.

3606109915
3606109875
99111341104
991113411AX
99111341202
99111341204
991113412AX

The product you are viewing cross references to these numbers
3606109918
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 991.1 Carrera / S

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.

3606109918
99111341104
991113411AX
99111341202
99111341204
991113412AX

The product you are viewing cross references to these numbers
3606109919
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 991.1 Carrera 3.4L 2012-2015
Porsche 991.1 Carrera S 3.82012-2015


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.

3606109919
99111341104
991113411AX
99111341202
99111341204
991113412AX

The product you are viewing cross references to these numbers
3606109916
Product Information
Product Information
Exhaust cat bypass pipes with gaskets.

designtek

Fits:
Porsche 991.1 Turbo / Turbo S

Porsche 991.2 Turbo / Turbo S

Free-flowing straight pipes replace the bulky & restrictive factory catalytic converters; designed specifically for maximum flow during racing or competition.

FEATURES:
• Maximizes power and throttle response while decreasing back pressure.
• Completely removes the catalytic converters for maximum exhaust flow and performance.
• Constructed from high-quality stainless steel for optimum flow and maximum durability.
• Direct replacement bolt-on for stock cat or Sport Cats

DISCLAIMER: This product removes the OEM catalytic converters from the vehicle, and as such, is strictly intended for closed track events and off-road use only. This product is or contains a Racing Cat Bypass Pipe, which will give you check engine lights on OBD2 cars. We suggest pairing this product with racing software to prevent fault codes and check engine lights. Racing Cat Bypass Pipes are solely intended for track and race cars as they are NOT California Air Resources Board Certified and not EPA certified. You are hereby informed and warned to check your local, state, and federals laws before buying and installing these or any aftermarket parts to be sure whether usage is in violation. All installation-risk and use-risk is borne by the end-user and installer of these parts.

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.

3606109916
99711301030
99711300930
997113010AX
997113009AX

The product you are viewing cross references to these numbers
FSPOR991TCB
Product Information
Product Information
Fabspeed Exhaust Cat bypass Pipes.

fabspeed

Increase exhaust flow from the headers to the mufflers and improving power and sound by removing the bulky and restrictive factory catalytic converter.

FEATURES:
Fits all 991 Turbo vehicles (2013+)
• Fabspeed's Cat bypass Pipes replace the restrictive factory catalytic converters with much less restrictive straight-through pipes for maximum flow and performance
• Noticeable increase in power and improved throttle response
• Saves 10 lbs in the rear of the vehicle versus the bulky factory catalytic converters
• Adds aggressive exhaust note for high performance sound
• Constructed from high-quality 14-16 gauge C.N.C. mandrel-bent T304L stainless steel for optimum flow and maximum durability
• Direct bolt-on replacement
• 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.

FSPOR991TCB
99711300930
997113009AX
99711301030
997113010AX

The product you are viewing cross references to these numbers
FSPOR991GT3CRX
Product Information
Product Information
Fabspeed Exhaust Catback Competition Race X-Pipe. 

The ultimate lightweight cat-back exhaust system for the 991 GT3 / GT3 RS saves 54lbs (24kg) off the rear of the vehicle and is perfect for competitive track use, high performance drivers education events, or aggressive street sound.

FEATURES:
• Fits all Porsche 991 GT3 / GT3 RS models (2014-2016)
 Perfect exhaust solution for maximum performance and sound during competitive track use, high performance drivers education events, or simply achieving an aggressive and exciting street sound.
   Saves over 54lbs (24kg) from the rear of the 991 GT3 which improves handling and acceleration by replacing the bulky factory center muffler and side mufflers
   Engineered and manufactured with 3" (76mm) T304L stainless steel tubing with integral tuned center X-Pipe to 70mm outlets.
   Bolt-on installation' no cutting or welding required
   Includes two (2) 90 degree Turndown Tips for track use.
   All Fabspeed performance products are backed by Fabspeed's Lifetime Warranty

NOTE: 
This is a straight pipe, racing oriented exhaust system built to be light and make power. As a result, the volume level will be very high inside the vehicle. 

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.

Please note: sports catalytic converters or bypass pipes do have type approval and may not be legally installed on vehicles manufactured after 1st March 2001. They can not be used on a public road and are not MOT compliant, they are designed for race and track cars only.


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

FSPOR991GT3CRX
FS.POR.991GT3.CRX
FS.POR.991GT3.CRX.BR
FS.POR.991GT3.CRX.CF

The product you are viewing cross references to these numbers
3606009130
Product Information
Product Information
Exhaust Muffler / Sport Switchable Race Exhaust System in Titanium DesignTek. With Cat bypass pipes.

designtek

Fits:
Porsche 991.1 S 3.8L

High quality titanium exhaust system for the Porsche 991.1. Manifold back exhaust that includes Catalytic converter bypass and tailpipes.

The silencers in this exhaust are linked to one another, creating a greater balance between the two silencers which improves flow, performance and provides a sports sound. It is a performance exhaust with a louder note and boasts significant power gains over OE system. This is race / offroad use only.

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.
99711152000/1
Product Information
Product Information
Exhaust sleeve catalytic converter to silencer.
Connecting sleeve from cat to rear silencer.
Price is for each sleeve.

oematch

Fits:
Porsche 996 1998-05 (not Turbo and GT2)

Porsche 997 2005>> (not Turbo and GT2)

Porsche 991 Carrera C2 3.4L (350Bhp)
Porsche 991 Carrera C2S 3.8L (400Bhp)
Porsche 991 Carrera C4 3.4L (350Bhp)
Porsche 991 Carrera C4S 3.8L (400Bhp)
   Fits cars with and without sport exhaust

Click 'Zoom in' for large parts diagram.
Diagram ref no 13



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

99711152000
99711152000
99611122002

The product you are viewing cross references to these numbers
Special Order item
99711152000
Product Information
Product Information
Exhaust sleeve catalytic converter to silencer.
Price is for each sleeve.

porsche

Original Porsche connecting sleeve from cat to rear silencer.

Fits:
Porsche 997 2005>> (not Turbo and GT2)
    Fits cars with and without sport exhaust

Porsche 991 Carrera C2 3.4L (350Bhp)
Porsche 991 Carrera C2S 3.8L (400Bhp)
Porsche 991 Carrera C4 3.4L (350Bhp)
Porsche 991 Carrera C4S 3.8L (400Bhp)

Click 'Zoom in' for large parts diagram.
Diagram ref no 13



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

99711152000
99711152000

The product you are viewing cross references to these numbers
99711152000/2
Product Information
Product Information
Titanium (grade 5) Exhaust sleeve catalytic converter to silencer.
Connecting sleeve from cat to rear silencer. Price is for each sleeve.

rohler

Fits:
Porsche 996 1998-05 (not Turbo and GT2)
Porsche 997 2005>> (not Turbo and GT2)
Porsche 991 Carrera C2 3.4L (350Bhp)
Porsche 991 Carrera C2S 3.8L (400Bhp)
Porsche 991 Carrera C4 3.4L (350Bhp)
Porsche 991 Carrera C4S 3.8L (400Bhp)

Fits cars with and without sport exhaust
Grade 5 titanium is resistant to salt water and variety of corrosive media temperatures below 300°C

Click 'Zoom in' for large parts diagram.
Diagram ref no 13



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

99711152000
99711152000

The product you are viewing cross references to these numbers
FSPOR991TSC
Product Information
Product Information
Fabspeed Exhaust Sport Catalytic Converters.

fabspeed

High-flowing, direct bolt-on replacement for the bulky & restrictive factory catalytic converters.

FEATURES:
Fits all 991 Turbo vehicles (2013+)
• Improves power and throttle response while decreasing back pressure
• High flow sport race cat for maximum flow and power.
• Constructed from high-quality 14-16 gauge T304L stainless steel for optimum flow and maximum durability
• Includes integrated O2 sensor bung for fuel-injected cars
• Direct replacement bolt-on for stock cat or cat bypass pipe

NOTE: Fabspeed's 200-cell high-flow catalytic converters are not C.A.R.B. certified and are for Off-Road Use ONLY in the state of California

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.

FSPOR991TSC
99711300930
997113009AX
99711301030
997113010AX

The product you are viewing cross references to these numbers
3606309105
Product Information
Product Information
Headers with 300 Cell Race Cats

designtek

High quality T304 Stainless steel equal length primary tubes. C.N.C. mandrel bent.

Designed for maximum flow and no restriction.

Reduced back pressure and better scavenging. More torque and horsepower across the RPM band.

Fits:
Porsche 991 GT3 3.8L 476 Bhp 2013 - 2017 (A175 engine)
Porsche 991 GT3 RS 4.0L 507 Bhp 2013 - 2017 (A175 engine)
Porsche 911 R 4.0L 507Bhp 2014-2017 (A176 engine)

Please note: This will not fit cars:
- with engine codes DNSA / DNSB - 4.0L with 520 Bhp
- released after 06/2017 with engine codes DGG / DGGA / DGGB

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.

3606309105
9A111302190
9A1113021CX
9A111302191
9A1113021AX
9A111302290
9A1113022CX
9A111302291
9A1113022AX

The product you are viewing cross references to these numbers
3606309106
Product Information
Product Information
Headers with Race Cat bypass

designtek

High quality T304 Stainless steel equal length primary tubes. C.N.C. mandrel bent.

Designed for maximum flow and no restriction.

Reduced back pressure and better scavenging. More torque and horsepower across the RPM band.

Fits:
Porsche 991.2 GT3 4.0L 500 Bhp 2017-2020 (DGG / DGGA engine)
Porsche 991.2 GT3 RS 4.0L 520 Bhp 2017 - 2020 (DGGB engine)

Please note: This will not fit cars:
- with engine codes DNSA / DNSB - 4.0L with 520 Bhp

Please note: These race cats will make your car sound significantly louder than with stock cats. Race track and off road use only.
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.

3606309106
9A111302195
9A1113021FX
9A111302295
9A1113022FX

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
TSPO991T13.403.ANK
Product Information
Product Information
Sports exhaust catalytic converter delete pipes Porsche 911 turbo and 911 turbo S 2013-2019
Fits both 991.1 and 991.2

tubi

Fits 2013-2019
Porsche 911 turbo 991.1
Porsche 911 turbo S 991.1
Porsche 911 turbo 991.2
Porsche 911 turbo S 991.2


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.

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.
DISPLAYING 1 to 16 (of 18 products)
1 2
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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