COBB Downpipe Updates

 

One of the first modifications generally made to a turbocharged car is an upgraded downpipe.  For over a decade, COBB downpipes have been the status quo when it comes time to upgrade your Subaru, Mazda, Mitsubishi, Ford, and more.  Featuring quality stainless tubing and CAD-designed cast bellmouths, our downpipes are the best fitting and most proven on the market.  This year, we set out to make the best downpipes available even better.  Our most popular downpipes are receiving updates to improve overall fitment, ease installation, and maximize durability.

What’s Changing?

GESi High Flow Catalytic Converters
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G-Sport by GESi prides itself on building the highest quality emissions solutions. To address the needs of performance enthusiasts all of their G-Sport models incorporate the company’s C3 Process in constructing each catalytic converter with high-grade stainless steel inside and out. Their metallic core is furnace-brazed and held in place with a Double-lock technology to ensure it will not telescope like lower-quality solutions on the market.  We have been working in partnership with GESi to create a proprietary catalyst for a number of our applications and will have more in-depth information regarding that process in an upcoming blog post and video.

Typical catalytic converters include ceramic substrates that have a higher rate of cracking, degradation or cause too much back pressure in a car’s exhaust. G-Sport Emissions Systems High Performance GEN1 Catalytic Converters are designed with a 304 stainless steel substrate for added durability. The substrate is then lined with nickel strips, and furnace-brazed to provide a solid bond throughout the core and to its mantle. This process, and our ‘Double-Lock’ transition cone application, ensure the core will not telescope or fail in high performance environments.

For best emissions control capabilities without performance degradation, G-Sport designed their high flow catalytic converters with 300 or 400 cells per square inch (CPSI). Their advanced substrate design, combined with a proprietary wash coat nano-technology, ensures the highest level of emissions reduction with comparable flow rates of similar 200 CPSI converters on the market.

3″ Cast Flange

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Introducing an all new cast stainless 2-bolt 3″ flange aids in both more precise assembly and also reduces stress during installation of the part.  Many downpipes utilize a laser cut plate flange at the termination point to the cat-back exhaust.  These plates are susceptible to minor warping while they are being welded to the tubing.  A cast flange is much more rigid and reduces the possibility of flex while exposed to extreme heat during assembly.  This rigidity also comes into play during installation of the downpipe.  In the past, we have received reports of warped flanges during installation due to over tightening of the hardware.  Over time, this deflection can lead to exhaust leaks.  The new cast version, combined with hardware improvements outline below, will not bend during installation and will allow for a much more reliable seal.

Improved Hardware

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Since their inception, our Subaru downpipes have necked down at the junction to the cat-back to allow for the use of the Subaru OE donut gasket.  There has long been a perception that this neck-down would create a significant reduction in airflow and limit power output.  Luckily, that is not true for an overwhelming majority of customers who retain the factory turbocharger or use a small frame bolt-on turbocharger.  In an effort to appease those who would like to take modifications beyond the basic bolt-on level, we have now utilized full 3″ tubing all of the way to the new 3″ cast flange described above.  This allows for direct compatibility of exhaust systems that use a 3″ flat flange.  For those who would rather continue to use the factory or factory-replacement cat-back exhaust systems, such as the COBB 3″ Stainless Steel Cat-Back, an adapter will now be included that allows for utilization of the OE donut gasket.  All new robust multi-layered steel gaskets are now included and provide a superior seal between the adapter and downpipe or to your 3″ flanged cat-back.

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We all know the struggle with factory spring bolts.  It’s a ballet of the fingers to get everything aligned, gasket in place, and apply just enough pressure to the spring to get the bolt threaded. An all new set of machined shoulder nuts, dubbed “B’s Nuts” internally, allow for trouble-free installation when utilizing factory spring bolts.  These nuts allow you to start threading the bolt prior to adding tension by compressing the spring.


Updated Downpipes

The following downpipes have received updates and are available for purchase at cobbtuning.com.

Mazda GESi Catted 3″ Downpipe – Mazdaspeed3 2007-2013

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The COBB GESi Catted 3″ Downpipe is one of the key upgrades for the MAZDASPEED3 to unluck a huge amount of torque hidden away within the MZR 2.3 DISI Turbo engine from the factory. Considerable effort was spent designing a flow path with the fewest number of directional changes and minimal degrees of bend in order to eliminate restrictions that have been found in the stock system. The COBB downpipe delivers significantly improved exhaust flow, resulting in faster turbo response time and power gains across the entire rev range.  This new version includes a GESi high flow catalytic converter that allows our Calibration Team to leave efficiency codes enabled in COBB created Off The Shelf Maps.


Subaru GESi Catted 3″ Downpipe STI 2008-2018, WRX 2008-2014, FXT 2009-2013

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The COBB Tuning GESi Catted 3″ Downpipe begins with a CAD designed cast bellmouth that smoothly blends air exiting the turbocharger’s turbine housing. Minimizing turbulence when exhaust gasses from the wastegate join into those flowing through the turbine helps to prevent excessive back-pressure. The cast housing is capped off with a COBB logo and auxiliary O2 bung for those wanting to install a wideband sensor early in the exhaust path.

A welded bracket utilizes the factory hard mount near the transmission reducing stress on the turbocharger mounting bolts and studs.

Corrosion resistant and mandrel bent 3″ 304 Stainless Steel tubing carries exhaust gasses down stream into a COBB-exclusive GESi 300 cell high flow catalytic converter. A second O2 bung is located directly after the catalytic converter and is to be used by the OEM Rear O2 sensor.

A CAD designed, cast 304 stainless steel, flange finishes off the tail section of the downpipe. The reinforced cast flange is less susceptible to warp during assembly and for those of you installing with the strength of The Hulk. A stainless adapter flange and included MLS gasket allows direct fit with the factory exhaust or COBB Cat-Back Exhaust utilizing the OEM donut gasket. Included COBB proprietary shoulder nuts allow for installation of the factory spring bolts without fuss.


Ford GESi Catted 3″ Downpipe Focus ST 2013-2018

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Free up your Focus ST’s exhaust flow with the COBB 3″ GESi Catted Downpipe!

This direct replacement for the factory downpipe features a 300 cell high flow catalytic converter and 304 stainless steel tubing. The CNC machined v-band flange and 4″ flex section ensure perfect OEM-like fitment at the turbocharger. We’ve added adjustability to the lower downpipe mount by slotting the attachment points.  This allows installers to custom-fit each downpipe to a specific car where tolerances may be slightly off.  Doing this reduces strain on the rubber isolaters, improving long-term reliability.  An all new cast stainless 2-bolt 3″ flange aids in both more precise assembly and also reduces stress during installation of the part. Many downpipes utilize a laser cut plate flange at the termination point to the cat-back exhaust. These plates are susceptible to minor warping while they are being welded to the tubing. A cast flange is much more rigid and reduces the possibility of flex while exposed to extreme heat during assembly. This rigidity also comes into play during installation of the downpipe. In the past, we have received reports of warped flanges during installation due to over tightening of the hardware. Over time, this deflection can lead to exhaust leaks. The new cast version will not bend during installation and will allow for a much more reliable seal. To cap it off, a multi-layer steel gasket is used between the downpipe and cat-back exhaust to make for a leak-free junction.

All of these features combine to provide a free flowing exhaust outlet for high energy exhaust gases to reduce turbo back pressure and increase turbo efficiency.

This downpipe is the perfect step towards Stage 3 power! Stage 3 off-the-shelf maps are available for the Focus ST Accessport for a perfectly tuned out-of-the-box experience.


Ford GESi Catted 3″ Downpipe Focus RS 2016-2018

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The COBB GESi Catted 3″ Downpipe is a direct replacement for the Focus RS’s factory downpipe. It features 3″ 304 stainless steel tubing, a 4’5″ diameter GESi catalytic converter, and high quality flanges on either end. A replacement Ford OE clamp is included for the flange at the cat-back junction.

This will probably be the only downpipe you will ever need for your Focus RS. It is compatible with our Stage2+ Off The Shelf maps but will also be the perfect starting point for big power builds with upgraded turbos!


Subaru GESi Catted 3″ Downpipe 2005-2009 Legacy GT / Outback XT Automatic

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The COBB Tuning GESi Catted 3″ Downpipe is one of the premier modifications most owners look to upgrade on their turbocharged Subaru. By increasing exhaust flow coming out of the turbocharger, an upgraded downpipe provides substantial power gains when combined with appropriate tuning.

The COBB Tuning GESi Catted 3″ Downpipe begins with a CAD designed cast bellmouth that smoothly blends air exiting the turbocharger’s turbine housing. Minimizing turbulence when exhaust gasses from the wastegate join into those flowing through the turbine helps to prevent excessive back-pressure. The cast housing is capped off with a COBB logo and auxiliary O2 bung for those wanting to install a wideband sensor early in the exhaust path.

A welded bracket utilizes the factory hard mount near the transmission reducing stress on the turbocharger mounting bolts and studs.

Corrosion resistant and mandrel bent 3″ 304 Stainless Steel tubing carries exhaust gasses down stream into a COBB-exclusive GESi 300 cell high flow catalytic converter. A second O2 bung is located directly after the catalytic converter and is to be used by the OEM Rear O2 sensor.

A CAD designed, cast 304 stainless steel, flange finishes off the tail section of the downpipe. The reinforced cast flange is less susceptible to warp during assembly and for those of you installing with the strength of Hulk. A stainless adapter flange and included MLS gasket allows direct fit with the factory exhaust or COBB Cat-Back Exhaust utilizing the OEM donut gasket. Included COBB proprietary shoulder nuts allow installation of the factory spring bolts without fuss.


Subaru GESi Catted 3″ Downpipe 2002-2007 WRX/STI, 2004-2008 Forester XT

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The COBB Tuning GESi Catted 3″ Downpipe is one of the premier modifications most owners look to upgrade on their turbocharged Subaru. By increasing exhaust flow coming out of the turbocharger, an upgraded downpipe provides substantial power gains when combined with appropriate tuning.

The COBB Tuning GESi Catted 3″ Downpipe begins with a CAD designed cast bellmouth that smoothly blends air exiting the turbocharger’s turbine housing. Minimizing turbulence when exhaust gasses from the wastegate join into those flowing through the turbine helps to prevent excessive back-pressure. The cast housing is capped off with a COBB logo and auxiliary O2 bung for those wanting to install a wideband sensor early in the exhaust path.

A welded bracket utilizes the factory hard mount near the transmission reducing stress on the turbocharger mounting bolts and studs.

Corrosion resistant and mandrel bent 3″ 304 Stainless Steel tubing carries exhaust gasses down stream into a COBB-exclusive GESi 300 cell high flow catalytic converter. A second O2 bung is located directly after the catalytic converter and is to be used by the OEM Rear O2 sensor.

A CAD designed, cast 304 stainless steel, flange finishes off the tail section of the downpipe. The reinforced cast flange is less susceptible to warp during assembly and for those of you installing with the strength of Hulk. A stainless adapter flange and included MLS gasket allows direct fit with the factory exhaust or COBB Cat-Back Exhaust utilizing the OEM donut gasket. Included COBB proprietary shoulder nuts allow installation of the factory spring bolts without fuss.

 


Subaru GESi Catted 3″ J-Pipe WRX 6MT 2015-2020 (Resonated and Non-Resonated)

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The COBB Tuning GESi Catted 3″ J-Pipe begins with a CAD designed 4″ cast bellmouth that smoothly blends air exiting the turbocharger’s turbine housing straight into the GESi High Flow Catalytic Converter. Minimizing turbulence when exhaust gasses from the wastegate join into those flowing through the turbine helps to prevent excessive back-pressure.

A welded bracket utilizes the factory hard mount near the transmission reducing stress on the turbocharger mounting bolts and studs.

Corrosion resistant and mandrel bent 3″ 304 Stainless Steel tubing carries exhaust gasses down stream into a COBB-exclusive GESi 300 cell high flow catalytic converter. A second O2 bung is located directly after the catalytic converter and is to be used by the OEM Rear O2 sensor.

A CAD designed, cast 304 stainless steel, flange finishes off the tail section of the J-Pipe. The reinforced cast flange is less susceptible to warp during assembly and for those of you installing with the strength of Hulk. A stainless adapter flange and included MLS gasket allows direct fit with the factory exhaust or COBB Cat-Back Exhaust utilizing the OEM donut gasket. Included COBB proprietary shoulder nuts allow installation of the factory spring bolts without fuss.

Available in both resonated and non-resonated.


Subaru GESi Catted 3″ J-Pipe WRX CVT 2015-2020, Forester XT 2014-2018

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The COBB Tuning GESi Catted 3″ J-Pipe for CVT WRX and Forester XT begins with a CAD designed 4″ cast bellmouth that smoothly blends air exiting the turbocharger’s turbine housing straight into the GESi High Flow Catalytic Converter. Minimizing turbulence when exhaust gasses from the wastegate join into those flowing through the turbine helps to prevent excessive back-pressure.

A welded bracket utilizes the factory hard mount near the transmission reducing stress on the turbocharger mounting bolts and studs.

Corrosion resistant and mandrel bent 3″ 304 Stainless Steel tubing carries exhaust gasses down stream into a COBB-exclusive GESi 300 cell high flow catalytic converter. A second O2 bung is located directly after the catalytic converter and is to be used by the OEM Rear O2 sensor.

A CAD designed, cast 304 stainless steel, flange finishes off the tail section of the J-Pipe. The reinforced cast flange is less susceptible to warp during assembly and for those of you installing with the strength of Hulk. A stainless adapter flange and included MLS gasket allows direct fit with the factory exhaust or COBB Cat-Back Exhaust utilizing the OEM donut gasket. Included COBB proprietary shoulder nuts allow installation of the factory spring bolts without fuss.

CUSTOM TUNING REQUIRED


Ford GESi Catted 3″ Downpipe Fiesta ST 2014-2019

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The COBB GESi Catted Downpipe for the Ford Fiesta ST is a direct replacement unit which features full 304 stainless steel construction, cast/machined turbo flange and a high quality GESi 400 cell catalytic converter. All of these features combine into an excellent replacement for the power robbing factory unit!


Coming Soon

Updated versions of COBB Downpipes for the following vehicles are currently being worked on and will be available in the near future.

  • 2015-2020 VW GTI/Audi A3 FWD
  • 2015-2020 VW Golf R/Audi S3, A3 AWD


COMMENTS
Jason Cheong on September 24, 2020 says:

do you have a rough ETA on when you’ll have the FocusRS DP updated? Keen for a DP as the next mod but don’t want to get one now and miss out on ‘new and improved’

Reply
    Marshall
    Marshall on September 30, 2020 says:

    We are hoping to have that one updated by the end of this year.

    Marshall@COBB

    Reply
Hristos Dalavikas on October 30, 2020 says:

Will You be producing downpipes for the BMW N54 e8x e9x in the foreseeable future?

Reply
    Marshall
    Marshall on November 2, 2020 says:

    We will no longer be offering BMW N54 downpipes.

    Marshall@COBB

    Reply
Brandon Vuong on November 5, 2020 says:

Any ETA on when the downpipes for WRX 2015-2020(6MT) will be released? Thanks

Reply
    Marshall
    Marshall on November 6, 2020 says:

    Hey Brandon, the J-pipes for 2015-2020 WRX are receiving some more significant changes and thus the timeline on them is a bit longer. We are hoping to have production runs of those in Spring of 2021.

    Marshall@COBB

    Reply
      Brad Smith on March 2, 2021 says:

      Checking in on the 2015-2020 MT WRX timeframe – still looking like spring? Itching to acquire one :)

      Reply
        Marshall
        Marshall on March 3, 2021 says:

        Hey Brad! Yeah, we’re still on track for a spring release – looks like we’re tracking toward late April/early May. – Marshall@COBB

        Reply
Stanislav Belchuk on November 6, 2020 says:

Any chance you’d be able to give me an ETA on the downpipe for the 2019 model year STI? Would love to go stage 2 without having to settle for another make.

Reply
    Marshall
    Marshall on November 16, 2020 says:

    The 2019 STI is going to require a different catalytic converter configuration (say that 5 times fast, haha) as it has to adhere to the updated CARB LEV III standards. We do not yet have an ETA for those downpipes and are continuing to test. Utilizing a downpipe that does not meet those standards may lead to a CEL when using our off the shelf maps.

    Marshall@COBB

    Reply
      Jasper Horng on November 27, 2020 says:

      If the 2019+ STi requires a “different cat configuration”, will a 2018 Cobb downpipe fit and thus can be tuned for?

      Reply
        Marshall
        Marshall on November 30, 2020 says:

        Will it fit? – Yes, it will physically bolt onto the car as the mechanical configuration is the same. Tuning is currently possible with the downpipe offered, but we’ll recommend changing to the 2019+ version once it is available as it will have superior emissions performance.

        Marshall@COBB

        Reply
      Dason Fernandez on March 12, 2021 says:

      Good afternoon,

      Is this updated downpipe expected to release for the 2019-2020 STI sometime this year?

      Thanks

      Reply
        Marshall
        Marshall on March 12, 2021 says:

        Hey Dason, we do not have an ETA for the 2019-2020 compatible downpipe at this time. I can tell you that we are continuing to work on it and are moving in the right direction, though!

        Marshall@COBB

        Reply
          Dason Fernandez on March 12, 2021 says:

          Thanks for the update Marshall. Last question:

          I read in the comments that the 2018 STI downpipe can physically bolt on to the 2019-2020 STI. Besides the CEL, would running this and the Stage 2 OTS map still work properly?

          Thanks

          Marshall
          Marshall on March 17, 2021 says:

          Hi Dason,

          It’s no secret that the downpipe configuration has not changed on the EJ powered WRX and STI since 2008. What HAVE changed, are emissions standards. Newer cars, such as the 2019-2020 STI, are held to a higher standard than previous MY cars utilizing the same mechanical configuration. We cannot recommend using our currently available downpipe for those specific vehicles and are hard at work developing a full solution.

          Marshall@COBB

Tyler Andrews on November 13, 2020 says:

Great news! Any idea when the ’07 WRX downpipes will be available?

Reply
    Marshall
    Marshall on November 16, 2020 says:

    We are aiming to have updated Subaru GD downpipes in early 2021, ideally Jan/Feb.

    Marshall@COBB

    Reply
      Peter Stasik on January 12, 2021 says:

      Is the ETA for the GD GESI catted DP still Jan/Feb?

      Reply
        Marshall
        Marshall on January 12, 2021 says:

        Yes, we are on track for early February.

        Marshall@COBB

        Reply
Akira Kumagai on March 17, 2021 says:

Would the current Stage 2 OTS tune from Cobb work with the new j-pipe for a 2018 WRX?

Reply
    Marshall
    Marshall on March 22, 2021 says:

    Hi Akira,

    We always recommend using the most up-to-date map file available for your vehicle and configuration.

    Marshall@COBB

    Reply
SEBASTIAN LAGANA on April 14, 2021 says:

Apologies for the potentially silly question, but as of today the best course of action for a 2019 STI seems to be catback for now and keep an eye out for the downpipe when available?

Reply
    Marshall
    Marshall on April 15, 2021 says:

    Yes, that would be our recommendation. Our upgraded cat-back (and some other options) are compatible with both the factory downpipe and would adapt well to an upgraded version in the future.

    Marshall@COBB

    Reply
Harry Taylor on June 10, 2021 says:

Hi, it’s been a while, so I’d like to ask – any updates on availability for a downpipe/stage 2 OTS option for the 2019+ STI?

And for that matter, I see that you recently released tunes for the 2021 WRX. Do you expect the Stage 1 tune for the 2021 STI to be available soon?

Thanks!

Reply
    Adam Hill
    Adam Hill on June 14, 2021 says:

    Hi Harry,

    The 21 STI updates is coming soon, hang in there!
    As for the revised downpipe, still undergoing testing. No specific ETA yet.

    Adam@COBB

    Reply
kieran gibson on July 18, 2021 says:

I live in Australia so wanting to run the aud stage 2 tune for a 2016 wrx. I have to option to buy the old 200 cell version or this new one with the gesi 300 cell. would either of these be suited for the most up to date cobb stage 2 tune? which to pick?

Reply
    Marshall
    Marshall on July 19, 2021 says:

    Hey Kieran,

    You would be able to use either J-pipe configuration in conjunction with the ADM version of our Stage 2 OTS file without issue.

    Marshall@COBB

    Reply