Catalyst / Bypass


- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
Replacement heat shield for Cat.

Fits:
Porsche 993 C2/4 1994-98 not turbo
Click 'Zoom in' for large parts diagram.
Diagram Ref No 19
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99321121402
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97

Standard Replacement Exhaust Catalytic Converter
Approved Petrol Cats made in grade T409 stainless steel.
Fits:
Porsche 993 C2 / C4 / C2S / C4S / RS 1994-98
Fits to BISCHOFF heat exchangers with gasket 93011119206
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Related, superseded, cross reference or alternative numbers for comparison.
99311321316
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
Fits:
Porsche 993 C2 / C4 / C2S / C4S / RS 1994-98
DesignTek sports catalytic bypass pipes, manufactured from T304 mandrel bent stainless steel. +15 emissions legal horsepower. Simple installation. Cat-back. Sportier/throatier than motor sound packages and other mufflers. Lightweight -saves 27 lbs. over stock therefore better handling. No cracking, splitting or failures like competitors systems! Greatly improved throttle response with lower engine temperature. System works well with all performance improvements.
Fitting this product might not pass a UK MOT approved.
Fits to BISCHOFF heat exchangers with gasket 93011119206 or GILLET heat exchangers with gasket 92811112702
Select below
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.
360620993
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97

Standard Replacement Exhaust Catalytic Converter
Approved Petrol Cats made in grade T409 stainless steel.
Fits:
Porsche 993 C2 / C4 / C2S / C4S / RS 1994-98
Fits GILLET heat exchangers with gasket 92811112702
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.
99311321343
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97

Fits : all Porsche 993 Carrera vehicles 1994-1998 - 3.6L / 3.8L and engines
Fabspeed's RSR Header Muffler Kit is a full exhaust system developed for track use provides an aggressive exhaust note while adding horsepower, torque, and throttle response; available as single or dual outlet and with or without heat exchange. Works great on street cars too. This Header/Muffler kit is built from the ground up to optimize performance for the Porsche 993 Carrera. Beyond just improving horsepower, torque, and throttle response, this package will also reduce the overall weight of your car by 43 pounds, which improves handling and acceleration.
SOUND:
This kit is designed specifically for use on the track, but works well for street drivers who want an aggressive and track-inspired exhaust note.
POWER:
We developed every inch of it to bring out the aggressive performance that the Carrera is capable of. On our dyno we saw gains of 29whp and 25ft/lbs of tq.
FEATURES:
• Loud and aggressive cup car sound
• 1.75" / 45mm Header tubes, 26" long
• This system can be ordered with single or double outlets
• Maintain your factory in-cabin heat with the optional heat exchange on the headers
• Saves 43lbs from the rear of the vehicle with heat exchange option, and saves 47lbs without heat exchange option
• Constructed from mandrel bent T304L stainless steel
• Simple DIY bolt-on installation, no cutting or welding required
• All Fabspeed performance products are backed by the Fabspeed Lifetime Warranty
NOTE:
This package can be purchased with a heat exchange on the headers that will help maintain the factory in-cabin heat. Without the exchange system, you'll save an additional 4 lbs, for a total of 47 pounds of weight reduction.
PURCHASE DISCLAIMER: Fabspeed Motorsport does not condone the use of emission defeat devices for any vehicles used on public streets or roadways. Fabspeed Motorsport will not tamper, remove, disable, or bypass emissions equipment on a motor vehicle in accordance with 40 CFR Section 86.1854.12(a)(3), Clean Air Act 40 CFR 1068.101(b). This includes software, known as tunes, that reprogram a motor vehicles electronic control module to alter engine performance and enable the removal of filters, catalysts, and other critical emissions controls.
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: 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.
FSPOR993RSRWH
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97

Composite gaskets included.
+8HP and significantly more torque.
Saves 11lbs/5kg over stock catalytic converters.
This new modular system includes a 200 cell German imported sport catalytic converter and cat bypass option in one interchangeable system.
993 Sport Catalytic Converter X-Pipe is different for certain years. 1994-1996 1/2 993's and all 993 SUPERCUP cars (1994 to 1997 993CUP) have Bischoff oval 3 bolt flanges. 1996+1998 993's are all Gillett round 3 bolt flanges. YOU MUST CORRECTLY specify flange type when Ordering.
When in doubt go check especially the late 1995 and early 1996 cars as this was a "cross-over year" and flange style changed during the year.
T304 Stainless steel C.N.C mandrel bent with polished show car mirror shine.
Simple and easy Bolt-on and bolt-off when you need to!.
Best PROVEN performance value on the market.
Might require blanking plug (90012300920) and washer (90021901500). Available separately.
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: 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.
FSPOR993
The product you are viewing cross references to these numbers




- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97

Composite gaskets included.
+8HP and significantly more torque.
Saves 11lbs/5kg over stock catalytic converters.
This new modular system includes a 200 cell German imported sport catalytic converter and cat bypass option in one interchangeable system.
993 Sport Catalytic Converter X-Pipe is different for certain years. 1994-1996 1/2 993's and all 993 SUPERCUP cars (1994 to 1997 993CUP) have Bischoff oval 3 bolt flanges. 1996+1998 993's are all Gillett round 3 bolt flanges. YOU MUST CORRECTLY specify flange type when Ordering.
When in doubt go check especially the late 1995 and early 1996 cars as this was a "cross-over year" and flange style changed during the year.
T304 Stainless steel C.N.C mandrel bent with polished show car mirror shine.
Simple and easy Bolt-on and bolt-off when you need to!.
Best PROVEN performance value on the market.
Might require blanking plug (90012300920) and washer (90021901500). Available separately.
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: 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.
FSPOR993
The product you are viewing cross references to these numbers




- 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
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche 997 MKII Carrera C2 3.6L 2009-12
- Porsche 997 MKII Carrera C4 3.6L 2009-12
- Porsche 997 MKII Carrera C2S 3.8L 2009-12
- Porsche 997 MKII Carrera C4S 3.8L 2009-12
- Porsche 997 MKII GT3 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
- Porsche 991.1 Carrera C2 3.4L (350Bhp) 2012-16
- Porsche 991.1 Carrera C2S 3.8L (400Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350Bhp) 2012-16
- Porsche 991.1 Carrera C4S 3.8L (400Bhp) 2012-16
- Porsche 991.1 Turbo 3.8L (520bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560Bhp) 2014-16
- Porsche 991.1 R 4.0L (500 Bhp) 2016
- Porsche 991.1 GT3 3.8L (475Bhp) 2014-16
- Porsche 991.1 GT3 RS 4.0L (500Bhp) 2015-16
- Porsche 991.2 Carrera 2 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Carrera 2S 3.0L (420 Bhp) 2016-19
- Porsche 991.2 Carrera 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Carrera 4S 3.0L (420 Bhp) 2016-19
- Porsche 991.2 Cabriolet 2 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Cabriolet 2S 3.0L (420 Bhp) 2016-19
- Porsche 991.2 Cabriolet 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Cabriolet 4S 3.0L (420 Bhp) 2016-19
- Porsche 991.2 Targa 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Targa 4S 3.0L (420 Bhp) 2016-19
- Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
- Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19
- Porsche 991.2 Speedster 4.0L (510Bhp) 2019
- Porsche 991.2 GT3 4.0L (500 Bhp) / GT3 RS 4.0L (520 Bhp) 2017-19
- Porsche 991.2 GT2 RS 3.8L PDK (700 bhp) 2018-19
- Porsche 992.1 Carrera 2 3.0L 2019-24
- Porsche 992.1 Carrera 4 3.0L 2019-24
- Porsche 992.1 Carrera 2 Cabriolet 3.0L 2019-24
- Porsche 992.1 Carrera 4 Cabriolet 3.0L 2019-24
- Porsche 992.1 Carrera 2S 3.0L 2019-24
- Porsche 992.1 Carrera 4S 3.0L 2019-24
- Porsche 992.1 Carrera 2S Cabriolet 3.0L 2019-24
- Porsche 992.1 Carrera 4S Cabriolet 3.0L 2019-24
- Porsche 992.1 Targa 4 3.0L 2020-24
- Porsche 992.1 Targa 4S 3.0L 2020-24
- Porsche 992.1 Speedster 4.0L 2019-24
- Porsche 992.1 Turbo 3.8L 2020-24
- Porsche 992.1 Turbo S 3.8L 2020-24
- Porsche 992.1 Turbo Cabriolet 3.8L 2020-24
- Porsche 992.1 Turbo S Cabriolet 3.8L 2020-24
- Porsche 992.1 GT3 4.0L / 992 S/T 4.0L 2021-24
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
- Porsche Cayman 2.7L 981 2013-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
- Porsche Cayman GT4 3.8L 2015-16
- Porsche Cayman 718 2.0L Manual (300Bhp)
- Porsche Cayman 718 2.0L PDK (300Bhp)
- Porsche Cayman S 718 2.5L Manual (350Bhp)
- Porsche Cayman S 718 2.5L PDK (350Bhp)
- Porsche Cayman T 718 2.0L Manual (300Bhp)
- Porsche Cayman T 718 2.0L PDK (300 Bhp)
- Porsche Cayman GTS 718 2.5L Manual (365 Bhp)
- Porsche Cayman GTS 718 2.5L PDK (365 Bhp)
- Porsche Cayman GTS 718 4.0L Manual (400 Bhp)
- Porsche Cayman GTS 718 4.0L PDK (400 Bhp)
- Porsche Cayman GT4 718 4.0L / GT4 RS 718 4.0L
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
The product you are viewing cross references to these numbers



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.