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Cobb Stage 2 - Downpipe, Midpipe & Muffer Installation

111K views 97 replies 45 participants last post by  Banman 
#1 · (Edited)
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.
 
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#2 · (Edited)
Re: DIY Cobb Stage 2

Remove the stock Turbo-back Exhaust (TBE):

1. Complete all Preparation Steps listed in the Original Post before continuing.

2. Remove the Rear Undercover. It is held on by 5 (12mm) bolts. A socket extension is needed to reach the 3 recessed holes. Removing the Undercover makes it easier to crawl under the vehicle. It also makes it easier to access the Muffler section exhaust hangers.



3. Unbolt the Muffler-to-Midpipe connection. Use a 14mm socket and a 14mm boxed/ratcheting wrench to remove the 2 nuts (14mm) and bolts (14mm) holding the Muffler section to the Midpipe section. I had to apply PB Blaster to these nuts and bolts twice. I then had to fit a 12" section of pipe over my 3/8" Drive Socket Wrench handle to produce enough torque to loosen these nuts and bolts. Carefully remove the stock gasket (Subaru Part #44022AA131) by gently tapping it from the side with a large flat-head screwdriver. If the gasket does not want to come out gently, wait until you have completely removed the Muffler section. Note: This connection sits between the gas tanks of your vehicle.



4. Once the Muffler-to-Midpipe connection is unbolted, remove the exhaust hanger closest to the driver's side at the rear of the muffler. This exhaust hanger is held in place by a 14mm bolt that threads into a 17mm welded nut. You can use a 17mm socket or boxed/ratcheting wrench to help stabilize the left side of the bracket, but DO NOT attempt to turn it as it will bend the bracket. Use a 14mm socket or boxed/ratcheting wrench to remove the inside bolt as shown in the picture below. You can leave the exhaust hanger attached to the Muffler, but remove the metal sleeve from the exhaust hanger since you will reuse it with the Cobb exhaust hanger.



5. Remove the other rear exhaust hanger. It pulls straight off of the blue peg, and it may require some persuasion. If you have difficulty moving it, try rotating the hanger back and forth as you pull on it. Once this exhaust hanger is removed, the Muffler section is only held in place by the exhaust hanger on the pipe.



6. While supporting the weight of the Muffler section (~20 lbs), remove the final exhaust hanger from the black metal peg shown in the picture below. If you have difficulty removing the exhaust hanger, try rocking the Muffler section back and forth as you pull on the hanger. With this exhaust hanger removed, the Muffler section will drop down. If you did not remove the stock gasket at the Muffler-to-Midpipe connection, do so now.



7. Unbolt the Midpipe-to-O2 connection. Use a 14mm socket and a 12mm boxed/ratcheting wrench to remove the 2 (14mm) bolts with springs and 2 nuts (12mm). Note the orientation of the springs as these nuts and bolts will be reused on the Cobb exhaust. The Midpipe section is now only held on by 1 exhaust hanger.



8. While supporting the weight of the Midpipe section (~10 lbs), remove the exhaust hanger from the blue peg shown in the picture below. The exhaust hanger may require some persuasion. If it is difficult to remove, rock the midpipe back and forth as you pull on the exhaust hanger. Once you remove the Midpipe section, the Doughnut gasket will be exposed on the O2 section.



9. The Doughnut gasket is a sleeved design and pulls straight off of the O2 section. A thin-tipped flat-head screwdriver can help you remove it if it wont budge. Gently stick the tip of the flat-head screwdriver behind the Doughnut gasket and lightly twist to force the gasket away from it's seated location. Save this gasket for reuse with the Cobb exhaust unless you've purchased a new gasket from Subaru (Part #44022AA122).



10. Remove the O2 Sensor from the O2 section. The slot in the O2 Sensor Socket is there to accomodate the wire when placing the socket over the sensor. Use the O2 Sensor Socket to loosen the sensor, but unscrew it by hand once it is loose to avoid wrapping the wire around the socket and possibly damaging it. If it's difficult to unscrew, you'll need to reseat the socket several times as you turn to avoid damaging the wire. Once the sensor is out, let it sit to the side of the O2 section. It will hang there by the wire. Be careful with the sensor and try to keep the probe area clean.



11. Unbolt the O2-to-Downpipe connection. One side of the connection has a nut (14mm) and bolt (14mm). The other side has a threaded stud that is held to the Downpipe with a nut (14mm). After you've removed these, the O2 section will remain in place due to the threaded stud and the hanger shown in step 12.



12. There is a 14mm bolt still holding the O2 Section to a metal hook that hangs down from the transmission. There is a welded nut on the back side of the hook that does not turn. Use a 17mm socket or wrench on the welded nut to stabilize the hook while you remove the 14mm bolt. Now you need to lift the O2 Section up slightly so that the bracket can clear the hook. Now lower the bracket past the hook while prying it back so that it does not catch. A large flathead screwdriver can help you pry it back as you lower the O2 Section. Remove the gasket that sat inbetween the O2-to-Downpipe connection.



13. Unbolt the Intercooler (optional). The Intercooler gets in the way of unbolting the stock heat shield and Downpipe section. It is possible to remove the heatshield and Downpipe section without removing the Intercooler. However, it can be difficult to reach the bolts if you decide not to remove it. The Intercooler is held in place by 1 bolt on each side. Use a 12mm socket with a socket extension to remove them. The bypass valve (brass colored with an "E" on it) is held to the Intercooler with 2 bolts. Use a 12mm socket with a socket extension to remove them as well. There are 2 black lines that are bracketed to the Intercooler with 2 smaller bolts. Use a 10mm ratchet-style/gear wrench to remove these. If you have an older model STI, these black lines might not be bracketed to the Intercooler.



14. Loosen the hose connections and remove the Intercooler. There is a red hose that connects to the turbo on the underside of the intercooler. Use a flathead screwdriver to loosen the clamp holding this hose to the intercooler. There is a black hose section that connects the front of the intercooler to the throttle body. Use a flathead screwdriver to loosen the clamp holding this hose to the throttle body. Now there is nothing holding the Intercooler down except a tight fit of the hoses. Wiggle the intercooler back and up towards the driver side. As it starts to loosen, tilt the backside of the intercooler up so that you can remove it. This can take some patience and slight persuasion. The aluminum tube behind the intercooler will be pushed back slightly as you pull the intercooler out. Store the intercooler in a clean location. I put mine in the trunk of my car. Small debri or trash that falls into the throttle body, turbo, or intercooler could cause damage later when the engine is run so be careful once the intercooler is removed.



15. Remove the stock heat shielding that sits over the turbo. It is held on by 7 small bolts (the number of bolts may vary by model year). Use a combination of a 10mm socket, 10mm deep socket, socket extension, and 10mm ratchet-style gear wrench to remove all of the bolts. Some of them can be difficult to reach. Once the heat shield is loose, you will need to hold the bottom of the shielding out a bit as you pull on it. It is slightly smaller at the bottom than the turbo housing and can take some persuasion as you pull it out.



16. Remove the Heatshield Bracket. It is held on by 2 nuts and 2 bolts. Use a 14mm socket and a 14mm ratchet-style/gear wrench to remove the nuts and bolts. Pull the bracket out and put the nuts and bolts back in place so that you do not lose them. See the 2nd picture.





17. Unbolt the Up-pipe Heat Shielding. You will not be able to remove this shielding until after the Downpipe section is removed, but having it loose helps reach some of the remaining nuts and bolts. It is held in place by 3 small bolts (the number of bolts may vary by model year). Use a combination of a 10mm socket, 10mm deep socket, socket extension, and 10mm ratchet-style gear wrench to remove all of the bolts. The 2nd picture shows one of the hard-to-see bolts sticking out just below the turbo housing.





18. Remove the 3 remaining nuts holding the Downpipe Bellmouth to the Turbo Housing, and remove the 1 bolt holding the Downpipe to the Transmission. The 3 nuts holding the downpipe to the turbo are found on the sides and bottom of the bellmouth. Use a combination of a 14mm socket, 14mm deep socket, and socket extension to remove these 3 nuts. The last bolt that holds the downpipe in place threads into the transmission housing. Use a 14mm ratchet-style/gear wrench to remove this bolt (the wrench location is shown in the picture).



19. The Downpipe section can now be removed. Pull the bellmouth off of the studs at the turbo. Lower the downpipe to the garage floor. Carefully remove the Bellmouth Gasket. This gasket is reused with the Cobb TBE unless you purchased a new one from Subaru. Now remove the Up-pipe heat shielding which should already be loose. To finish removing the downpipe, you'll need to get under the car and maneuver it out (rotate it as you pull). With the downpipe removed, be careful not to let any trash or debri into the turbo's outlet since it is exposed. Congratulations. You've removed your stock Turbo-back Exhaust (2nd and 3rd picture).





 
#3 · (Edited)
Re: DIY Cobb Stage 2

Install the Cobb Turbo-back Exhaust (TBE):

1. Check the sleeved surface of the Cobb Downpipe just behind the catalytic converter at the flange. It should be fairly smooth. Remove any dirt, debri, or roughness that could cause an exhaust leak. Press the old or new Doughnut Gasket onto the end of the Cobb Downpipe. If you can swivel the installed gasket, do so and remove any metal flakes that fall off. I noticed some metal flakes falling back into the catted section when I put the gasket on and swiveled it.



2. Position the Cobb Downpipe into place from underneath the vehicle. Do not bolt the Cobb Downpipe to the turbo or hook yet. Let it sit on the garage floor with the bellmouth sitting up in the engine bay just below the turbo. There is not enough room to install the O2 Sensor with a Torque Wrench if you bolt the Downpipe to the turbo.

3. Free the O2 Sensor wire. The O2 Sensor wire may be held in place by a plastic clip. Unfortunately, this clip prevents you from being able to move the O2 Sensor into place on the Downpipe. If you can, disconnect the white clip. I found this clip to be difficult and resorted to taking a pair of pliers to cut the clip in two, freeing the O2 Sensor for installation.

4. Install the O2 Sensor. Put a small amount of antiseize on the threads of the O2 Sensor. Be careful not to get any antiseize on the sensor probe. One trick to this installation is to turn the O2 Sensor the wrong way several rotations by hand before attempting to thread it in. This will twist the wire backwards so that when you thread the O2 Sensor in by hand, it will not be twisted. Use the O2 Sensor Socket to tighten the O2 Sensor to 26 ft-lbs of torque.

5. In the engine bay, check the turbo's face to make sure it is free of dirt, debri, or roughness that could cause an exhaust leak. Place the old or new Bellmouth Gasket onto the turbo. The gasket will only go on one way due to the 3 threaded studs.

6. Put a small amount of antiseize on the 3 studs protruding from the turbo. Lift the bellmouth of the Cobb Downpipe onto the studs. Start threading the 14mm nuts onto these studs, but do not tighten them all the way. You still want some play in the downpipe.

7. From underneath the vehicle, persuade the Cobb Downpipe onto the hook that hangs down. Start threading the 14mm bolt into the hook, but do not tighten it. It will be tightened after the turbo nuts and bolts are tightened.





8. Install the Heat Shield Bracket to the bellmouth of the Cobb DP and tighten the Bellmouth-to-Turbo connection. The 3 nuts (14mm) should be tightened to the threaded studs with 26 ft-lbs of torque. The 2 nuts (14mm) and 2 bolts (14mm) holding the Heat Shield Bracket should also be tightened to 26 ft-lbs of torque. Remember to put antiseize on the 2 bolts for the Heat Shield Bracket.





9. Follow-up the Cobb Downpipe installation by tightening the bolt that goes into the hook underneath the car. Use a flat head screwdriver to hold the bracket away from the exhaust pipe before you tighten the bolt. If the bracket sits too close to the pipe, it will rattle for a few seconds when you first start up your car. Expansion of the hot metal makes it go away shortly after startup. It was very annoying and took me a while to find. Tighten the bolt with 26 ft-lbs of torque. Shake the Cobb Downpipe back and forth to make sure it is secure.



10. Install the Cobb Heatshield. Start by threading these 2 bolts (10mm) through the Cobb Heatshield and into the Heatshield Bracket. Do not tighten them since you want some play in the heatshield for threading in the 3rd bolt (10mm). The 3rd bolt threads in at the bottom of the Heatshield directly below the last "B" on the inscribed "COBB" logo. It can be difficult to reach, but I found it easy if I twisted my right hand 180 degrees inward with my palm facing the Heatshield.





11. Reinstall the Intercooler. It goes back on the same way it came off. Line up the red and black hose as best you can before trying to push them into place. Try to push them into place at the same time. If the red or black hose starts to bend inward instead of sliding over, you can use a thin tipped screwdriver to correct it. Gently put the thin tipped screwdriver under one side of the hose and slowly roll the screwdriver around to the side that is folded inward. This will force it outward so that it can be slid over the connection. Retighten the hose clamps and bolts to the proper torque specs laid out in your vehicles Service Manual.

12. Install the Cobb Midpipe Section.

13. Install the Cobb Muffler Section along with the 3" gasket.

14. Reinstall the Rear Undercover.
 
#4 · (Edited)
Re: DIY Cobb Stage 2

Reflash the ECU with Stage 2 v1.04 using the APv2:

With your Cobb exhaust installed, you need to reflash the base map on the ECU to Cobb Stage 2 93 Octane or Cobb Stage 2 91 Octane depending on which fuel is available to you. Cobb's Accessport comes with an Instruction CD and Printed Quick Start Guide. The Instruction CD should have a more detailed manual available in PDF format. Read the manual for this portion. Technology tends to change and I do not want someone to accidently brick their computer by not following the instructions for their model.
 
#8 ·
Re: DIY Cobb Stage 2

This looks great! I will definitely be using these instructions
If you could just add in extra info on when u say -remove intercooler -remove downpipe section
(for newb proof or whoever that doesnt have a manual)
Add extra info on how many bolts to remove and highlight the bolts to be removed?
 
#10 ·
Re: DIY Cobb Stage 2

This looks great! I will definitely be using these instructions
If you could just add in extra info on when u say -remove intercooler -remove downpipe section
(for newb proof or whoever that doesnt have a manual)
Add extra info on how many bolts to remove and highlight the bolts to be removed?
:D This is a rough rough draft. I'll finish it soon enough, though. I place the pictures, figure out how I want to structure it, and go back to refine it before I take the first line out of the thread "This is a work in progress". There will be a lot more detail before I am through. It takes time to do it right.
 
#9 ·
Re: DIY Cobb Stage 2

Came out very nice, thanks for taking the time.
 
#14 ·
Re: DIY Cobb Stage 2

How many hours did the disassembly take? Nice DIY write up!
Thankyou, but the writeup isn't even 1/2 complete yet.

As for time, you can estimate 4-6 hours if you have everything you need and you are doing it for the first time. Having done it once, it would take me much less time (~2 hours). The writeup will hopefully reduce the time it takes you to get it done the first time. Once you've removed the stock exhaust, the assembly of the Cobb exhaust is much much easier. You can also combine some steps that I have separated out in the DIY such as removing/installing the muffler/midpipe sections as 1 piece.
 
#15 ·
Re: DIY Cobb Stage 2

Great write-up!! Very nice and detailed with many pics that helps ppl that have never, or would have never done this!! I really need to start keeping my camera in mind when doing mods myself to help the community!!

Big props for a nice detailed write-up!!:tup:
 
#17 · (Edited)
Re: DIY Cobb Stage 2

Few more question.
1. The big question is do you like the performance, exhaust sound and access PORT of the Cobb system?
port?
2. Is the exhaust louder than the stock? Do you have sound bit?
3. Do you have a picture of the Cobb DP installed?
1. I like the exhaust note. The Cobb AP is what a lot of people call a turn-key solution. With Cobb's AP, I don't need to know how to tune cars for a simple power and performance increase. Just make the exhaust changeout and follow the instructions sent with the AP to reflash your Engine Management. That being said, this is a How To thread. This thread does not address the pros and cons of installing a Stage 2 package. The ECU forums cover the topic extensively.

2. The exhaust is slightly louder than stock. Try youtube for a sound and video clip.

3. As stated before, this writeup is not complete. I am still working on it. It will probably be another week before I attach those pictures and add the details of how to install and flash.
 
#18 ·
Re: DIY Cobb Stage 2

Update: The first post (Overview) and second post (Stock TBE Removal) are complete. Proofread if you please and let me know if anything is confusing with those portions. I'll continue writing the Cobb TBE installation portion this weekend.

Thankyou.
 
#24 ·
Re: DIY Cobb Stage 2

I didn't realize you have to take the intercooler off to remove the stock turbo heat shield... I'm hoping this is unnecessary for the '08s.
This DIY was performed on a 2007 STI. Cobb says that it is not always necessary to remove the Intercooler. When I looked at it, though, I could not find a way to do it without removing the intercooler.

The 08 may be different.
 
#27 ·
Re: DIY Cobb Stage 2

Hey guys,
I am planning on doing this project by myself, but i have very little experience working on cars. Would it be possible for someone of my ability to install these components without any complications. Or would it be better to have a shop install it for me? Im planning on doing this work in my garage, so i was curious as to how difficult it would be.
I would appreciate it if anyone had some input or opinions on this subject. Thanks
 
#28 ·
Re: DIY Cobb Stage 2

Hey guys,
I am planning on doing this project by myself, but i have very little experience working on cars. Would it be possible for someone of my ability to install these components without any complications. Or would it be better to have a shop install it for me? Im planning on doing this work in my garage, so i was curious as to how difficult it would be.
I would appreciate it if anyone had some input or opinions on this subject. Thanks
The only real difficulty is that the nuts and bolts are very hard to get loose. Make sure you know how to jack up and secure your car safely. If you don't like getting frustrated with bolts that don't turn, have a shop install it. It will take them about 45 minutes with a lift which will cost around $200 - $300 labor.

If you don't have the tools, do not attempt.

If you're a part of a local Subi chapter, club, or regional forum, you might find someone that would love to help you. Make sure you compensate them for gas, time, etc.
 
#30 ·
Re: DIY Cobb Stage 2

Great write-up!

I just did the full cobb tbe installation today and the biggest problem we ran into was getting the midpipe donut gasket to fit the cobb downpipe. We did everything without having to remove the intercooler. It wasn't horribly easy or horribly hard, so removing it may make it easier.

Luckily we didn't break any bolts or run into any other problems...but after I read this, we didn't put any anti-seize on the turbo bolts, just the o2 sensor, is this going to be a problem?
 
#39 ·
I used this...my 06 has some stubborn bolts holding the downpipe to the turbo. I've hit them with PB Blaster a few times and heat cycled them...just can't get them loose yet. I'll try again next week one night. LOL The catback was cake...the diffuser wasn't in the way on my 06.
Another option is a cheater bar. The longer the ratchet you have the better. You can take a pipe 1 ft. to 3 ft. in length and put it over your ratchet handle to gain additional leverage.

I recommend shopping the plumbing isle at Lowes for galvanized pipe sections that can just barely fit over your ratchet handle.
 
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