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Catalyst / Bypass
The Fabspeed Porsche 964 Turbo / 965 / C2 Turbo Secondary Muffler Bypass Pipe is a performance exhaust upgrade designed to replace the factory secondary rear muffler with a freer-flowing stainless-steel pipe.
Fits:
- Porsche 964 (911) TURBO 3.3L 1990-94
- Porsche 964 (911) TURBO 3.6L 1990-94
Designed for both 3.3L and 3.6L Porsche 964 Turbo / 965 models, the bypass pipe reduces restriction in the rear exhaust system while retaining the vehicle's catalytic converter. This provides improved exhaust flow, sharper throttle response, reduced rear-end weight and a more pronounced turbocharged flat-six exhaust note.
Manufactured from 14–16 gauge CNC mandrel-bent T304L stainless steel, the pipe is a direct replacement for the original Porsche secondary muffler.
Fabspeed lists 12 HP and 10 lb-ft for this product and states that removing the factory secondary muffler saves approximately 25 lb / 11.4 kg from the rear of the vehicle. Performance figures are manufacturer-reported and actual results will vary according to vehicle specification, condition and testing environment.
What This Product Does:
The secondary muffler is positioned downstream of the catalytic converter and is primarily responsible for reducing exhaust noise before gases exit through the rear exhaust tip.
While effective at controlling sound, the internal chambers and passages of a conventional muffler can also create resistance to exhaust flow.
The Fabspeed Secondary Muffler Bypass Pipe removes this muffler and replaces it with a freer-flowing pipe.
The upgrade is designed to provide:
- Improved exhaust-gas flow
- Reduced rear exhaust restriction
- Improved throttle response
- Increased performance potential
- Reduced rear-end weight
- Stronger turbocharged flat-six exhaust sound
- More pronounced turbo whistle
- More direct exhaust path
Improved Exhaust Flow:
Replacing the factory secondary muffler removes internal chambers and sound-control structures from this section of the exhaust.
The resulting straighter exhaust route is designed to reduce restriction.
Potential benefits include:
- Faster exhaust-gas evacuation
- Reduced backpressure
- Improved turbo exhaust flow
- Sharper throttle response
- Improved performance throughout the RPM range
The exact difference will depend on the condition and specification of the complete engine and exhaust system.
Enhanced Turbocharged Flat-Six Sound:
Removing the secondary muffler allows considerably more of the 964 Turbo's natural exhaust character to be heard.
The result is a deeper and more pronounced turbocharged flat-six sound, accompanied by increased turbo whistle.
Drivers can expect:
- Deeper exhaust tone
- Increased exhaust presence
- Stronger sound under acceleration
- More noticeable turbo whistle
- More pronounced flat-six character
- Sportier overall exhaust note
The final sound will depend on the rest of the exhaust system fitted to the vehicle.
Why Upgrading Matters:
The original secondary muffler does not need to have failed before this component is installed.
This product is primarily a performance, sound and weight-reduction upgrade.
Reasons for upgrading include:
- Removes the restrictive factory secondary muffler
- Improves exhaust flow
- Improves throttle response potential
- Manufacturer-listed 12 HP / 10 lb-ft
- Approx. 25 lb / 11.4 kg rear weight saving
- Stronger turbocharged flat-six sound
- More noticeable turbo whistle
- Retains the catalytic converter
- T304L stainless-steel construction
- CNC mandrel-bent tubing
- Direct replacement for the factory secondary muffler
- Suitable for both 3.3L and 3.6L 964 Turbo applications
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.
FSPOR964TSMB
The product you are viewing cross references to these numbers
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
Fits:
Porsche 930 3.0L Turbo 1975-77
Porsche 930 3.3L Turbo 1978-89
Porsche 964 Turbo 3.3L-3.6L 06/1991-07/1993
Please note:
This part will fit most of cars straight away but some may require alteration.
Porsche made a few different versions of the pipe over the years which all had a slightly different shape. (although Porsche used one number)
If this pipe is out you would need to loosen all the bolts on the exhaust system (Including the turbo) and mount the pipe into place afterwards.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011100304
The product you are viewing cross references to these numbers
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
Fits:
Porsche 930 3.0L Turbo 1975-77
Porsche 930 3.3L Turbo 1978-89
Porsche 964 Turbo 3.3L-3.6L 06/1991-07/1993
Please note:
This part will fit most of cars straight away but some may require alteration.
Porsche made a few different versions of the pipe over the years which all had a slightly different shape. (although Porsche used one number)
If this pipe is out you would need to loosen all the bolts on the exhaust system (Including the turbo) and mount the pipe into place afterwards.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93011100304SS
The product you are viewing cross references to these numbers
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
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
- 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 / GT3 RS 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 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
- Porsche 991.1 Carrera C2 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
- Porsche 991.1 R 4.0L (500 Bhp) 2016
- Porsche 991.1 GT3 3.8L (475 Bhp) 2014-16
- Porsche 991.1 GT3 RS 4.0L (500 Bhp) 2015-16
- Porsche 991.2 Carrera 2 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Carrera 2S / GTS 3.0L (420/450 Bhp) 2016-19
- Porsche 991.2 Carrera 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Carrera 4S / GTS 3.0L (420/450 Bhp) 2016-19
- Porsche 991.2 Cabriolet 2 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Cabriolet 2S / GTS 3.0L (420/450 Bhp) 2016-19
- Porsche 991.2 Cabriolet 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Cabriolet 4S / GTS 3.0L (420/450 Bhp) 2016-19
- Porsche 991.2 Targa 4 3.0L (370 Bhp) 2016-19
- Porsche 991.2 Targa 4S / GTS 3.0L (420/450 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 / GTS 3.0L 2019-24
- Porsche 992.1 Carrera 4S / GTS 3.0L 2019-24
- Porsche 992.1 Carrera 2S / GTS Cabriolet 3.0L 2019-24
- Porsche 992.1 Carrera 4S / GTS Cabriolet 3.0L 2019-24
- Porsche 992.1 Targa 4 3.0L 2020-24
- Porsche 992.1 Targa 4S / GTS 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 (300 Bhp)
- Porsche Cayman 718 2.0L PDK (300 Bhp)
- Porsche Cayman S 718 2.5L Manual (350 Bhp)
- Porsche Cayman S 718 2.5L PDK (350 Bhp)
- Porsche Cayman T 718 2.0L Manual (300 Bhp)
- 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
Fits:
Porsche 964 Turbo (965) 1991-92
Porsche 964 Turbo (965) 1993-94
Kit Contents:
Fabspeed’s high-flow sport headers are designed to retain full cabin heat functionality while unlocking noticeable performance gains. Thanks to a shorter exhaust gas path and smooth mandrel bends, these headers dramatically improve exhaust flow - boosting power, sharpening throttle response, and reducing turbo lag, with boost onset up to 1500 RPM earlier than stock. They also deliver a mild increase in volume, a more pronounced turbo spool sound, and a deeper, more aggressive exhaust tone.
- Constructed from 14-16ga CNC mandrel-bent T304L stainless steel with high velocity F1-style merge collectors for optimum exhaust flow.
- This system will include a drip accumulator with double swivels and Aeroquip lines with adaptors, plus graphite steel layered gasket for a leak proof seal.
- 7/8"custom braided oil lines with correct 30mm radius Porsche style ball end with OEM fittings will be included to replace the stock oil lines.
- Retains the stock cabin cockpit heat functionality.
- Simple DIY (Do-It-Yourself) bolt-on installation, no cutting or welding required.
- Backed by Fabspeed's Lifetime Warranty.
Fabspeed's Maxflo dual outlet muffler delivers a deep, aggressive exhaust note along with a significantly enhanced turbo spool sound—bringing out the true character of your 964 Turbo.
- Includes Fabspeed's Deluxe Outlet Tips; polished angle-cut ovals.
- Maxflo Mufflers are radius stress relieved, hydro-formed cases that are pulse TIG welded with 2000 degree ceramic fiber and stainless steel wool packing.
- Constructed from high-quality 14-16 gauge C.N.C. mandrel-bent T304L stainless steel for optimum flow and maximum durability.
- Complete 3.0" tubing for maximum flow.
- Includes 4.5" wastegate tip and all required hardware.
- Simple DIY (Do-It-Yourself) bolt-on installation, no cutting or welding required.
- Backed by Fabspeed's Lifetime Warranty.
Fabspeed’s high-performance intake system replaces the outdated, heavy steel factory airbox found on 930 and 964 Turbo (965) models - a design originally from the 1970s and '80s that traps heat like a Dutch oven and severely limits airflow. This factory setup bakes the intake air, reducing performance and efficiency. In contrast, Fabspeed’s Cold Air Intake is engineered to reduce weight and deliver significantly cooler, denser air directly to the engine - resulting in dyno-proven horsepower and torque gains.
- Saves maintenance time, and weighs much less, for better handling and cooler engine temperatures.- Increases horsepower and torque by +17.5 HP and +26 ft-lbs.
- Significant weight savings along with finally an uncluttered CLEAN to BE SEEN awesome engine bay.
- Cleans up engine bay for easier access for maintenance and car shows!
- Allows fitment of larger intercoolers versus banging into the steel heavy airbox.
- Supports up to 550+ horsepower.
- VIDEO- installation instructions and photos online. Super simple engineered system.
- Used and installed by a WHOs WHO of Porsche Turbo engine builders Worldwide!
- CAD Designed and DYNO developed 100% Guaranteed to be the very best air intake for your 964 Turbo!
- Backed by Fabspeed's Lifetime Warranty.
FITMENT NOTE: After the initial heat cycle, be sure to retighten all exhaust bolts to OEM torque specs to ensure a proper, lasting seal.
NOTE: This system replaces the factory catalytic converter with a high-flow setup and is not MOT compliant, meaning it is intended for race and track use only and must not be used on public roads. If you are located outside the UK, please check your local laws and regulations to ensure compliance before installation.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
FSPOR964TSPKG
The product you are viewing cross references to these numbers
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
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.