GV / VA / VB Subaru Catback


GV / VA / VB Subaru Catback

WRX Sedan 2008 - 2023
WRX STi Sedan 2008 - 2021

Congratulations on your purchase of the COBB Tuning Subaru STI Catback. The following instructions will assist you through your installation process. Please read them first BEFORE beginning the install and familiarize yourself with the steps and tools needed. If you feel that you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.

Part List

  • Straight Pipe
  • Y-Pipe
  • Driver's Side Muffler
  • Passenger's Side Muffler
  • 2x M8 x 25mm Flange Bolt
  • 6x M10 Bolts
  • 6x M10 Nuts
  • 3" Flange Gasket
  • 2x 2.5" Flange Gasket
  • 4x 63-68mm exhaust clamp

Tools Needed

  • Ratchet
  • Sockets: 14mm, 13mm, 12mm
  • Optional: Exhaust Hanger Removal Tool, Silicone Lubricant, anti seize

Removal of Stock Catback

  1. Begin the removal process by loosening and removing the spring bolts holding the stock catback to the downpipe. Use a 14mm and 12mm to do so. NOTE: Keep this hardware, it will be used during the installation of the COBB Catback.

  2. Go ahead and take the donut gasket off of the end of the downpipe so that it is not damaged by potentially falling to the ground. 

  3. There are 5 exhaust hangers that need to be removed from grommets so that the stock catback can be uninstalled. Remove the 4 hangers in the back that support the two mufflers first and then remove the hanger that is supporting the center of the catback. It is recommended that two people are used for this job!


  4. Once the exhaust hangers are removed from the grommets, the catback should fall out of place. 

Installation of COBB STI/WRX Catback

  1. To install the COBB Catback, it is easiest to install on the car as an assembled piece rather than part by part. 

  2. Use the hardware provided to bolt the catback together. Be sure that you place a flange gasket between each flange! The 3" gasket connects the straight pipe to the Y-pipe and the two 2.5" gaskets are used to connect the Y-pipe to the two muffler sections. Use a 14mm wrench or socket to tighten all of the hardware, and make sure that the flanges line up when you are tightening.

  3. Install the COBB Catback by first placing the middle hanger in the grommet.

  4. Now place the remaining 4 hangers near the mufflers in the stock grommets.

  5. With the catback being supported by the hangers, you can now place the donut gasket onto the downpipe. Next use the supplied nuts that slot neatly inside the cast flange on the engine side of the exhaust then slip the two m8x25mm bolts (with a small dab of anti-seize) to loosely fit the two flanges together for now.

  6. Examine the fitment of your exhaust and adjust the flanges where needed so that it sits cleanly without hitting anything.  Then tighten down starting in the back and moving forward.

  7. Slip the 4 supplied exhaust clamps over the muffler section.  You may want to add a little of the provided anti-seize to prevent stripping them out.

  8. Push the exhaust tips on.  You can line them up in whatever configuration and distance you want! Once you're happy with the look, tighten the 4 clamps down with your 10mm socket.  Make sure the hardware of the clamps isn't facing somewhere it will rub on the bumper or other clamp.

  9. Double check to make sure that all of the nuts and bolts are nice and tight!  Enjoy your new COBB Catback!
    Y-Pipe Flange 35ft-lbs
    Spring Bolt 13 ft-lbs


COBB Product Install Instructions for Subaru Vehicles 

Main Installation Instruction Repository for Subaru Parts

Calibration Map Notes for Subaru Vehicles

Link to Subaru Map Notes to see what map you should be on given the parts you've added

Contact Us:

COBB Customer Support

Web Support and Tech Articles: COBB Tuning Customer Support Center

Email: support@cobbtuning.com

Phone support available 9am to 6pm Monday-Thursday. 9am to 4pm Friday (CST)


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