Scope:
The following process is loosely based on the Cobb 2002+ WRX/STI Downpipe, Cat-back Exhaust, and Heatshield Installation Instruction Sets. The following process is intended to help you remove your stock Turbo-back Exhaust, install your Cobb Turbo-back Exhaust w/ Heatshield, and reflash the ECU with the Stage 2 v1.04 map using the Cobb APv2. This write-up assumes that the reader is using Cobb & Subaru OEM parts unless otherwise specified.
Difficulty (4/10):
Removing and installing the exhaust is a straight-forward bolt-on project. However, removing the exhaust can be difficult since the nuts and bolts holding it in place have undergone many heating and cooling cycles. These nuts and bolts can be VERY difficult to loosen. I sprayed these nut and bolt locations with a loosening agent, and I still needed additional leverage (12" pipe) to remove them. It is also possible to shear off bolts when working on an exhaust system which might require drilling them out. The other aspect that makes this project difficult is access. Some of the nuts and bolts are located in very hard to reach locations. A variety of sockets, socket extensions, and wrenches is necessary to reach some of the locations. Depending on how high you jack the car up, you will have limited access to turn and move while working under the vehicle. The last difficulty is trying to remove and mount the exhaust sections while balancing their weight.
Disclaimer:
When in doubt, have a qualified technician or maintenance shop perform the Cobb Stage 2 installation. The following procedure contains guidelines for installing the Cobb Stage 2 Package on a stock 2007 STI and may not accurately reflect your particular car's exhaust system. Read the 'Exhaust' sections of your Service Manual and Cobb's OEM Instruction Set first before you perform the Stage 2 Installation. For the 2007 STI, Cobb recommends using a catted downpipe due to possible boost spiking while running catless. This DIY is designed to assist you with installation. It does not tell you the pros and cons of installing a Stage 2 package. You also should consult federal and state laws concerning the use of an aftermarket catalytic converter on the street. Do your research.
Safety:
Your car's exhaust system becomes very hot during vehicle operation. Allow at least 1 hour for the exhaust system and engine bay to cool before performing any work to avoid getting a burn. If your exhaust system or engine bay components are still hot to the touch after 1 hour, allow the system to cool longer. Avoid spilling any materials on the exhaust system during this process as they could potentially smoke and catch fire. Wipe any residue off of the exhaust system before operating the vehicle. Never operate the vehicle with the exhaust removed or loose. Make sure that the correct vehicle ECU map (Cobb Stage 1, 2, or stock) is installed for the correct exhaust system (Cobb Stage 1, 2, or stock) before operating the vehicle. Using the wrong ECU map for the wrong exhaust system will damage your engine and/or turbo. Only operate your vehicle when the installation is complete. Your vehicle weighs ~3,000+ lbs. Jack it up and secure it properly as outlined in your Subaru Owner's and/or Service Manual. When working on your vehicle, always wear the proper safety equipment (gloves and safety glasses).
What To Wear:
Gloves
Long Sleeve Shirt
Safety Glasses
Note: Wear gloves and long sleeves to avoid getting a sheet metal cut from the stock heat shielding and other sheet metal components found on and around the exhaust system. The nuts and bolts holding the exhaust system together can be very tight due to heat expansion and contraction. One slip of the wrench can mean a hospital visit to get stitches. Wear safety glasses to keep rust, dirt, and other foreign objects from falling into your eyes. A good amount of small particles and flakes will fall down while you work under the vehicle.
Tools:
Low Profile Jack with at least 3,000 lb rating
4 Jackstands with at least 2 ton rating for each pair (and any other supplemental support)
Headlamp or Flashlight
Torque Wrench (3/8" drive recommended)
2 Socket Wrenches (3/8" drive recommended)
Socket Extensions
10mm Socket
12mm Socket
14mm Socket
17mm Socket (optional for securing welded nut on Muffler exhaust hanger)
19mm Socket (optional if you purchased M12 nuts and bolts from Lowes)
10mm Deep Socket
12mm Deep Socket
14mm Deep Socket
19mm Deep Socket (optional if you purchased M12 nuts and bolts from Lowes)
10mm Allen Socket or Allen Wrench (for the bung plug installation on the Cobb Downpipe)
10mm Ratchet-Style/Gear Wrench
12mm Ratchet-Style/Gear Wrench
14mm Ratchet-Style/Gear Wrench
Large Flat-head Screwdriver
Thin-tipped Flat-head Screwdriver
12" Steel or Galvanized Pipe (for adding additional leverage to your Socket Wrench; purchased from Lowes plumbing section)
O2 Sensor Socket (shown below) or a 22mm wrench
Materials:
Penetrating Spray Lubricant (PB Blaster shown on left)
Anti-seize Lubricant (Permatex brand anti-seize shown on right)
Parts:
Here is a link to Cobb's 2004-2007 STI Parts Page for reference:
CobbTuning.com - Power
1 Cobb Accessport v2
1 Cobb Turbo-back Exhaust (TBE) consisting of a Muffler Section (top), a Midpipe Section (middle), and a Downpipe Section (bottom)
1 Bellmouth Exhaust Gasket (for the Turbo to Downpipe connection; you can reuse the stock gasket or purchase a new one from Subaru: 44022AA180)
1 Doughnut Exhaust Gasket (for the Downpipe to Midpipe connection; you can reuse the stock gasket or purchase a new one from Subaru: 44022AA122)
The picture below shows the stock gaskets left to right as they appear in order from the stock Downpipe to the stock Muffler.
The 1st and 3rd gaskets from left to right are reused with the Cobb TBE (Bellmouth and Doughnut gasket).
The 2nd and 4th gaskets from left to right are not reused with the Cobb TBE.
2 M12-1.25 x 45mm Hexhead Bolts (for the Midpipe to Muffler connection; available at Lowes)
2 M12-1.25 Hexhead Nuts (for the Midpipe to Muffler connection; available at Lowes)
1 3" Exhaust Gasket (for the Midpipe to Muffler connection; I do not have a specification for the bolt spacing)
Cobb Tuning sends 2 Nuts, 2 Bolts, and a 3" Gasket with the Stage 2, TBE, or CBE purchase.
4 Cobb Exhaust Hangers
1 Cobb Heat Shield (the stock heat shielding can be trimmed to accomodate the Cobb downpipe at the turbo; this DIY does not cover the trimming procedure)
Another IWSTI user made this DIY, though, that covers a trimming procedure:
http://www.iwsti.com/forums/how-ins...tock-turbo-heat-shield-fit-bell-mouth-dp.html
Preparation:
1. Check that you have all of the parts and tools necessary for installation.
2. Make sure all components are clear of manufacturing residue and packing materials before installation.
3. Put some anti-seize on the threads of the Bung Plug. Install the Bung Plug into the top of the bellmouth (shown in the picture below) using a 10mm Allen Wrench or Socket and tighten it to at least 25 ft-lbs of torque. If your Bung Plug is already installed and tightened beyond measure, don't mess with it. I've included this step here to make sure you have the Bung Plug prior to starting the installation. Cobb provides the Bung Plug with the purchase of the TBE, but it may be the case that your TBE did not come with one. The Bung Plug has standard Bosch threads if you do not want to wait on Cobb to ship you one.
4. Park on a level surface and turn off the engine.
5. Secure the car from rolling by engaging the parking brake and putting the car in reverse after the engine is turned off. Use wheel chocks as necessary.
6. Put the car up level on all 4 jack stands. Always reference your Subaru Owner's and/or Service Manual first for the proper procedure. It will not hurt to put additional support under the car in the unlikely event that the car's weight should shift or a jack stand or support member should fail. Whenever possible, do not place your body directly under the car when it is elevated on jack stands. It's also a good idea to have someone else nearby when working under a vehicle. In the picture, I used 2 x 12 cut boards as additional support under the tires. This is not sufficient with a stackup of only 2 boards, but gives you an idea of how you can provide supplemental support to the jack stands in case of failure.
7. Pop the engine hood and allow the engine to cool for at least 1 hour.
8. After the engine is cool, spray all of the exhaust nuts and bolts with Penetrating Spray Lubricant. Wait 30 minutes or more before attempting to remove any nuts and bolts.
System Overview:
The stock exhaust system has 2 catalytic converters, 4 pipe sections, and bolt-on heat shielding that covers the turbo (2nd picture), up-pipe (3rd picture), and catalytic converters. The stock exhaust system is held on by a series of nuts, bolts, and exhaust hangers.
The Cobb exhaust system has 1 catalytic converter (unless you ordered the catless version which is not recommend for the 07 STI). The Cobb exhaust system has 3 pipe sections. The Cobb exhaust system is too large to reuse the stock heat shielding sections. Cobb makes a heat shield for the turbo, but it is possible to trim the stock heat shield for reuse at this location if you wish to maintain a stock-like appearance in the engine bay. I have not covered any trimming procedures in this DIY. The Cobb exhaust system is designed to reuse 2 of the stock exhaust system gaskets as listed in the Parts section above. The 3" Midpipe-to-Muffler gasket with 2 nuts and bolts is included with the Stage 2 Package, TBE, or CBE purchase. Be careful when removing the TBE, so that the stock exhaust gaskets can be reused. You can also purchase new stock exhaust gaskets from your local Subaru dealership.
The following process is loosely based on the Cobb 2002+ WRX/STI Downpipe, Cat-back Exhaust, and Heatshield Installation Instruction Sets. The following process is intended to help you remove your stock Turbo-back Exhaust, install your Cobb Turbo-back Exhaust w/ Heatshield, and reflash the ECU with the Stage 2 v1.04 map using the Cobb APv2. This write-up assumes that the reader is using Cobb & Subaru OEM parts unless otherwise specified.
Difficulty (4/10):
Removing and installing the exhaust is a straight-forward bolt-on project. However, removing the exhaust can be difficult since the nuts and bolts holding it in place have undergone many heating and cooling cycles. These nuts and bolts can be VERY difficult to loosen. I sprayed these nut and bolt locations with a loosening agent, and I still needed additional leverage (12" pipe) to remove them. It is also possible to shear off bolts when working on an exhaust system which might require drilling them out. The other aspect that makes this project difficult is access. Some of the nuts and bolts are located in very hard to reach locations. A variety of sockets, socket extensions, and wrenches is necessary to reach some of the locations. Depending on how high you jack the car up, you will have limited access to turn and move while working under the vehicle. The last difficulty is trying to remove and mount the exhaust sections while balancing their weight.
Disclaimer:
When in doubt, have a qualified technician or maintenance shop perform the Cobb Stage 2 installation. The following procedure contains guidelines for installing the Cobb Stage 2 Package on a stock 2007 STI and may not accurately reflect your particular car's exhaust system. Read the 'Exhaust' sections of your Service Manual and Cobb's OEM Instruction Set first before you perform the Stage 2 Installation. For the 2007 STI, Cobb recommends using a catted downpipe due to possible boost spiking while running catless. This DIY is designed to assist you with installation. It does not tell you the pros and cons of installing a Stage 2 package. You also should consult federal and state laws concerning the use of an aftermarket catalytic converter on the street. Do your research.
Safety:
Your car's exhaust system becomes very hot during vehicle operation. Allow at least 1 hour for the exhaust system and engine bay to cool before performing any work to avoid getting a burn. If your exhaust system or engine bay components are still hot to the touch after 1 hour, allow the system to cool longer. Avoid spilling any materials on the exhaust system during this process as they could potentially smoke and catch fire. Wipe any residue off of the exhaust system before operating the vehicle. Never operate the vehicle with the exhaust removed or loose. Make sure that the correct vehicle ECU map (Cobb Stage 1, 2, or stock) is installed for the correct exhaust system (Cobb Stage 1, 2, or stock) before operating the vehicle. Using the wrong ECU map for the wrong exhaust system will damage your engine and/or turbo. Only operate your vehicle when the installation is complete. Your vehicle weighs ~3,000+ lbs. Jack it up and secure it properly as outlined in your Subaru Owner's and/or Service Manual. When working on your vehicle, always wear the proper safety equipment (gloves and safety glasses).
What To Wear:
Gloves
Long Sleeve Shirt
Safety Glasses
Note: Wear gloves and long sleeves to avoid getting a sheet metal cut from the stock heat shielding and other sheet metal components found on and around the exhaust system. The nuts and bolts holding the exhaust system together can be very tight due to heat expansion and contraction. One slip of the wrench can mean a hospital visit to get stitches. Wear safety glasses to keep rust, dirt, and other foreign objects from falling into your eyes. A good amount of small particles and flakes will fall down while you work under the vehicle.
Tools:
Low Profile Jack with at least 3,000 lb rating
4 Jackstands with at least 2 ton rating for each pair (and any other supplemental support)
Headlamp or Flashlight
Torque Wrench (3/8" drive recommended)
2 Socket Wrenches (3/8" drive recommended)
Socket Extensions
10mm Socket
12mm Socket
14mm Socket
17mm Socket (optional for securing welded nut on Muffler exhaust hanger)
19mm Socket (optional if you purchased M12 nuts and bolts from Lowes)
10mm Deep Socket
12mm Deep Socket
14mm Deep Socket
19mm Deep Socket (optional if you purchased M12 nuts and bolts from Lowes)
10mm Allen Socket or Allen Wrench (for the bung plug installation on the Cobb Downpipe)
10mm Ratchet-Style/Gear Wrench
12mm Ratchet-Style/Gear Wrench
14mm Ratchet-Style/Gear Wrench
Large Flat-head Screwdriver
Thin-tipped Flat-head Screwdriver
12" Steel or Galvanized Pipe (for adding additional leverage to your Socket Wrench; purchased from Lowes plumbing section)
O2 Sensor Socket (shown below) or a 22mm wrench
Materials:
Penetrating Spray Lubricant (PB Blaster shown on left)
Anti-seize Lubricant (Permatex brand anti-seize shown on right)
Parts:
Here is a link to Cobb's 2004-2007 STI Parts Page for reference:
CobbTuning.com - Power
1 Cobb Accessport v2
1 Cobb Turbo-back Exhaust (TBE) consisting of a Muffler Section (top), a Midpipe Section (middle), and a Downpipe Section (bottom)
1 Bellmouth Exhaust Gasket (for the Turbo to Downpipe connection; you can reuse the stock gasket or purchase a new one from Subaru: 44022AA180)
1 Doughnut Exhaust Gasket (for the Downpipe to Midpipe connection; you can reuse the stock gasket or purchase a new one from Subaru: 44022AA122)
The picture below shows the stock gaskets left to right as they appear in order from the stock Downpipe to the stock Muffler.
The 1st and 3rd gaskets from left to right are reused with the Cobb TBE (Bellmouth and Doughnut gasket).
The 2nd and 4th gaskets from left to right are not reused with the Cobb TBE.
2 M12-1.25 x 45mm Hexhead Bolts (for the Midpipe to Muffler connection; available at Lowes)
2 M12-1.25 Hexhead Nuts (for the Midpipe to Muffler connection; available at Lowes)
1 3" Exhaust Gasket (for the Midpipe to Muffler connection; I do not have a specification for the bolt spacing)
Cobb Tuning sends 2 Nuts, 2 Bolts, and a 3" Gasket with the Stage 2, TBE, or CBE purchase.
4 Cobb Exhaust Hangers
1 Cobb Heat Shield (the stock heat shielding can be trimmed to accomodate the Cobb downpipe at the turbo; this DIY does not cover the trimming procedure)
Another IWSTI user made this DIY, though, that covers a trimming procedure:
http://www.iwsti.com/forums/how-ins...tock-turbo-heat-shield-fit-bell-mouth-dp.html
Preparation:
1. Check that you have all of the parts and tools necessary for installation.
2. Make sure all components are clear of manufacturing residue and packing materials before installation.
3. Put some anti-seize on the threads of the Bung Plug. Install the Bung Plug into the top of the bellmouth (shown in the picture below) using a 10mm Allen Wrench or Socket and tighten it to at least 25 ft-lbs of torque. If your Bung Plug is already installed and tightened beyond measure, don't mess with it. I've included this step here to make sure you have the Bung Plug prior to starting the installation. Cobb provides the Bung Plug with the purchase of the TBE, but it may be the case that your TBE did not come with one. The Bung Plug has standard Bosch threads if you do not want to wait on Cobb to ship you one.
4. Park on a level surface and turn off the engine.
5. Secure the car from rolling by engaging the parking brake and putting the car in reverse after the engine is turned off. Use wheel chocks as necessary.
6. Put the car up level on all 4 jack stands. Always reference your Subaru Owner's and/or Service Manual first for the proper procedure. It will not hurt to put additional support under the car in the unlikely event that the car's weight should shift or a jack stand or support member should fail. Whenever possible, do not place your body directly under the car when it is elevated on jack stands. It's also a good idea to have someone else nearby when working under a vehicle. In the picture, I used 2 x 12 cut boards as additional support under the tires. This is not sufficient with a stackup of only 2 boards, but gives you an idea of how you can provide supplemental support to the jack stands in case of failure.
7. Pop the engine hood and allow the engine to cool for at least 1 hour.
8. After the engine is cool, spray all of the exhaust nuts and bolts with Penetrating Spray Lubricant. Wait 30 minutes or more before attempting to remove any nuts and bolts.
System Overview:
The stock exhaust system has 2 catalytic converters, 4 pipe sections, and bolt-on heat shielding that covers the turbo (2nd picture), up-pipe (3rd picture), and catalytic converters. The stock exhaust system is held on by a series of nuts, bolts, and exhaust hangers.
The Cobb exhaust system has 1 catalytic converter (unless you ordered the catless version which is not recommend for the 07 STI). The Cobb exhaust system has 3 pipe sections. The Cobb exhaust system is too large to reuse the stock heat shielding sections. Cobb makes a heat shield for the turbo, but it is possible to trim the stock heat shield for reuse at this location if you wish to maintain a stock-like appearance in the engine bay. I have not covered any trimming procedures in this DIY. The Cobb exhaust system is designed to reuse 2 of the stock exhaust system gaskets as listed in the Parts section above. The 3" Midpipe-to-Muffler gasket with 2 nuts and bolts is included with the Stage 2 Package, TBE, or CBE purchase. Be careful when removing the TBE, so that the stock exhaust gaskets can be reused. You can also purchase new stock exhaust gaskets from your local Subaru dealership.