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Thread: The Exhaust, Downpipe, and Manifold Thread.

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    The Catback Exhaust, Downpipe, and Manifold Thread.

    As of 3/8/2012 this list is incomplete.

    I invite all Elite members to edit this post for both accuracy and to include any and all relevant information. Extrapolation and expounding on covered topics is also an excellent idea, but anything more than a brief overview should be linked to a separate thread.


    Seeing as there is no thread (that I can find) containing information on the various exhausts available for WRX/STI's, I thought I'd piece this together to help everyone out. All fitment needs to be double checked before ordering as in most cases there are multiple fitments available (i.e. hatch and sedan models). Prices gathered from various vendors, and are approximated. I will list all available cat-back exhausts, downpipes, and exhaust manifold's currently available both new and used.

    For a detailed technical discussion, please visit The Exhaust Design and Exhaust Theory thread.

    TBE = Turbo Back Exhaust (Includes Downpipe) *REQUIRES TUNE*
    CBE = CatBack Exhaust (Does not include Downpipe)
    OTS = Off the Shelf, usually referring to an AccessPort tune
    Stage 1 = Basic Reflash of the computer, can be done totally stock or in addition to an intake
    Stage 2 = Flash for the addition of a downpipe
    Protune = A professional tune, which is superior to an OTS tune in regard to power, safety, and longevity. Research your choice in tuner extremely carefully.
    Exhaust Manifold = Typically called a "header"



    For best results, seek a full 3 inch turbo back exhaust.



    Catalytic converter back Exhausts, or Catbacks.


    To start, the cat back portion of the exhaust does not typically require a tune. That being said most people start off their modifying with an intake (tune required), a CBE, and an OTS stage 1 tune. Adding a downpipe also requires a tune, and can be done on it's own (no CBE or intake) with either an AP stage 2 tune, or a protune. If you are not currently using any type of flash device to tune the car or a have tuner to tune the car, it is imperative you do not do any modification that changes the airflow characteristics of the motor. Any time you add additional performance parts to the car it must be tuned for these new modifications. Certain exhausts are available as both a CBE and TBE, or as only one or the other. For that reason the "Type" column shows how it is available.

    The CBE portion of your exhaust is the part that determines the majority of the sound, and has a very small (~3%) effect on performance. It will consist of the axle back portion as well as the midpipe. Most CBE's can be swapped for each other with no need to re-tune. You will want to re-tune however, when either the size of the piping or flow characteristics change drastically. Assuming all else being equal however, the CBE is primarily for personal preference of both sound and aesthetics. For the GR they come in various styles including single exit, dual exit, dual exit quad tipped, angled exit(s), stainless tips, or even burnt titanium tips (personal favorite) all of which range in price and volume. To be added upon relative completion of this list will be approximate decibel ratings.

    GR WRX/STI 2008 - 2012 Exhausts
    Model Type Cost
    Agency Power SS CBE $750.00
    Agency Power Ti CBE $850.00
    AMR TBE* $1,900.00
    Apexi Megaphone CBE $650.00
    ARK Performance CBE/TBE* $950.00 (CBE)
    $1,500.00 (TBE)
    Blitz Nut Spec R TBE* $2,000.00
    Borla CBE $925.00
    CNT Performance CBE/TBE* $350.00 (CBE)
    $700.00 (TBE)
    COBB CBE $1,200.00
    Crawford CBE $750.00
    Crawford Gymkhana CBE $400.00
    Fast Motorsports CBE $340.00
    Fujibitsu CBE $900.00
    Greddy Spectrum Elite CBE $1,500.00
    HKS ES TBE* $1,750.00
    HKS Legmax TBE* $2,000.00
    Invidia Q300 CBE $850.00 (Stainless Tip)
    $975.00 (Titanium Tip)
    Invidia N1 CBE $725.00 (Stainless Tip)
    $900.00 (Titanium Tip)
    Lachute Performance CBE/TBE* $1,500.00 (CBE)
    $1,800.00 (TBE)
    Magnaflow CBE $900.00
    Miltek TBE* $1,850.00
    Nameless CBE $1,200.00
    P&L CBE $1,000.00 (Cannister or Quad Tip)
    Perrin Single Tip CBE $1,000.00
    Perrin Quad Tip CBE $1,200.00
    SPT CBE $900.00
    Turbo XS CBE $715.00
    Turbo XS TBE* $1,120.00
    Ultimate Racing CBE $750.00


    GD WRX/STI 2004-2007 Exhausts
    Model Type Cost
    AMS CBE $640.00
    Apexi GT Spec CBE $900.00
    Apexi N1" CBE $700.00
    Blitz Nur Spec R CBE $680.00
    Blitz Nur Spec R Touring CBE $800.00
    Borla Hush CBE $640.00
    Borla XR-1 CBE $665.00
    BPM GT CBE
    BPM Twister II CBE
    Buddy Club Spec III CBE
    Cobb 3" CBE
    Crawford CBE
    Crawford Gymkhana CBE
    Fujitsubo Legalis CBE
    Fujitsubo Power Getter CBE
    Fujitsubo RM01A CBE
    Greddy Evo/Evo 2 CBE
    Greddy Sp2 CBE
    Greddy TI CBE
    Helix Titanium CBE
    HKS Carbon TI CBE
    Invidia G200 CBE
    Invidia N1 Race/Street CBE
    JIC 505S CBE
    MadDad Whisper CBE
    Megan Racing CBE
    Perrin CBE
    Prodrive CBE
    RS*R CBE
    SPT CBE
    Tanabe Medallion CBE
    Turbro XS CBE
    Turbo XS RFL-Ti CBE




    Downpipes



    A downpipe is the portion of the exhaust the portion where the most power can be gained, or at least initially in a car that is mostly stock form. This piece connects the hotside of the turbo to the midpipe, and replaces the extremely restrictive stock 2.5 inch downpipe. They will come both with and without catalytic converters. In most states you will NOT pass emissions without a catalytic converter. The downside of having a cat however is that sooner or later it will need to be replaced, and that (according to some) it can at times make less power than having a catless downpipe instead.

    The term "stage 2" will typically refer to a modified car with a full turbo-back exhaust. Subaru's offer two different types of after market downpipes, the bellmouth which is a downpipe with a oval shaped opening that is open to all the exhaust from the turbo and the divorced which has a similar opening to the bellmouth but incorporates a metal piece to separate the exhaust gasses coming from the wastgate and the turbo itself. For a detailed explanation on the differences between various types/sizes/materials used, please see this thread here.

    GR WRX/STI 2008-2012 Downpipes
    Model Catalytic Converter Material Width Cost
    Cobb Catted Bellmouth Yes 304 Stainless 3 Inches - Tapered to 2.5 - No Flex Joint $600.00
    Injen Divorced V1 Yes 304 Stainless 3 Inches - No Taper/Flex Joint $550.00
    Injen Divorced No 304 Stainless 3 Inches - No Taper/Flex Joint $420.00
    Invidia Divorced V1 Yes 304 Stainless 3 Inches - No Taper/Flex Joint $500.00
    Invidia Catless Divorced


    $300.00
    Invidia Catless Bellmouth


    $250.00
    Nameless Performance


    $600.00
    Tomei Expreme Catless Bellmouth


    $375.00
    TurboXS Catless Bellmouth


    $315.00


    GD WRX/STI 2002-2007 Downpipes
    Model Catalytic Converter Material Width Cost
    Cobb Bellmouth Yes 304 Stainless 3 Inches - Tapered to 2.5 - No Flex Joint $600.00
    HKS Bellmouth No 304 Stainless 3 Inches - No taper/Flex Joint $450.00
    Injen Bellmouth Yes 304 Stainless 3 Inches - No taper/Flex Joint $550.00
    Invidia Divorced Yes 304 Stainless 3 Inches - No Taper/Flex Joint $500.00
    Invidia Bellmouth No 304 Stainless 3 Inches - No Taper/Flex Joint $250.00
    Invidia V2 Bellmouth No 304 Stainless 3 Inches - No Taper/Flex Joint - 2 O2 Bungs $275.00
    Invidia V3 Divorced No 304 Stainless 3 Inches - No Taper/Flex Joint $290.00
    Turbo XS Bellmouth No 304 Stainless 4 Inch Bellmouth to 3 Inch Piping - No Flex Joint $315.00




    Exhaust Manifolds, or "Headers".
    As almost all manifolds fit model years 2002-2012, this will be a one chart section. As such, confirm all fitment before purchasing as there may be minor differences for each manifold across the model years. Additionally, a considerable amount of manifolds include their own up-pipe section. I will include a column at the end to note if said manifold includes this piece. Additional information on up pipes can be found below this section.

    The reason Subaru's (specifically FI models) have the trademark "rumble" is the design of the exhaust manifold. The uneven "pulses" from the pistons creates this effect. Manifolds are a highly detailed and technical subject and the debate between UEL and EL continues to rage on, but the general accepted truths are that an equal length manifold will have a much more even pulse distribution and shorter primaries to the collectors. Because of this, EL manifolds will typically nets larger gains, faster throttle response, quicker spool, and more top end power. The trademark "Boxer Rumble" however is no longer as present, and as such many individuals continue to run an UEL manifold to preserve the iconic sound. High horsepower cars can and do continue to be built using UEL, but often at a sacrifice of power as compared to EL.


    WRX/STI 2002-2012 Exhaust Manifolds
    Model Features Runners Cost Includes
    Up-Pipe
    ETS Equal Length 2.0 Diameter Big Turbo, 1.5 Diameter Stock. 2 Bolt Up-Pipe connection Equal Length $850.00 No
    GTSpec 45mm Primaries, 304 Stainless Steel.
    3 Bolt Up-Pipe connection
    Both Equal and Unequal $630.00 Yes
    HKS 42mm Primaries, 409 Stainless Steel Equal Length $630.00 No
    HKS 304 Stainless Steel. 2 Bolt Up-Pipe connection Unequal Length $1,250.00 No
    Invidia 304 Stainless Steel Equal Length $1,025.00 Incorporated
    Invidia Big Piping 38mm-49mm Primaries, 304 Stainless Steel Equal Length $1,025.00 Incorporated
    Invidia Race 42mm Primaries, 304 Stainless Steel Equal Length $875.00 No
    KillerB Holy Header 321 Stainless Steel - Full Review Here Equal Length $1,400.00 No
    LiteSpeed 304 Stainless Steel - Dyno Results Here Unequal Length $700.00 No
    Nameless Equal Length *Not Yet Released Equal Length *Not Yet Released *Not Yet Released
    Tomei Equal Length 304 Stainless Steel with a 3 Bolt Up-Pipe connection.
    4-2-1 Design with 42.7mm-45mm-60mm.
    Equal and Unequal Length $750.00 Yes

    Note: A variety of sources were used in the making of this post and while nothing has been directly copied, it can be stated that all information posted has a verifiable basis in fact and is not speculation. The moderators and ElitSTI team have/will continue to monitor this post for as much accuracy and foundation in fact as possible.

    Last edited by R3V; 03-16-2012 at 09:48 AM.

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    Awesome post man. here is another down pipe for the 08+
    http://store.crawfordperformance.com/store/products/95

    Ill take a crack at explaining the Divorced down pipe.

    From what i understand the stock turbos on subarus have a waste gate built into the hot side of the turbo which is to control boost pressure. when peak pressure is reached any excess gasses adding too much pressure is released through a valve. A divorced waste gate down pipe separates excess gas from the rest to alleviate turbulence and maintain smooth exhaust flow. I have see 2 types:

    ones that are bellmouth shaped but have a separating plate


    and ones that have a separate pipe and redirect the gas a little further down the pipe


    Hope i got that right

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    Updated.

  4. Top Of Page | #4
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    Updated Manifolds and started updating Downpipes. Please post additional models and suggestions!

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    System Operator IGOTASUBARU's Avatar

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    Quote Originally Posted by R3V View Post
    Updated Manifolds and started updating Downpipes. Please post additional models and suggestions!
    Good job. You trying for elite status here also, lol.
    Without you, we cease to exist. Without your support, we stop growing. Without your involvement, we remain at a standstill.
    Thank you for your faithfulness to our organization and your creative ideas and support.



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    Quote Originally Posted by CRZTRBO View Post
    Good job. You trying for elite status here also, lol.
    I didn't even know Elite existed until after I made this and Ed mentioned it. Then George sent me a PM, and now here I am. I actually thought I read it transferred over here too?

    I actually started the thread here, since I got FB messages from the igotasubaru group asking about exhausts. It kinda snowballed. I don't mind writing stuff like this, teaching/putting everything in words helps me learn as much as it does help others. Win/win!

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    It does transfer, but only for sponsors on the site. Thanks again for all the great post.
    Without you, we cease to exist. Without your support, we stop growing. Without your involvement, we remain at a standstill.
    Thank you for your faithfulness to our organization and your creative ideas and support.



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    Awesome info.


    Any info on how hard it is to get the bolts un-done on the up pipe or down pipe? Do they get stuck and break often?

  9. Top Of Page | #9
    System Operator IGOTASUBARU's Avatar

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    Re: The Exhaust, Downpipe, and Manifold Thread.

    Quote Originally Posted by DjWRX View Post
    Awesome info.


    Any info on how hard it is to get the bolts un-done on the up pipe or down pipe? Do they get stuck and break often?
    Spray them a few days before you want to unbolt them. I use Pb blaster. All I can is spray spray, and spray.
    Without you, we cease to exist. Without your support, we stop growing. Without your involvement, we remain at a standstill.
    Thank you for your faithfulness to our organization and your creative ideas and support.



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