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  1. #1
    Senior Member Two Rings
    Join Date
    Sep 12 2014
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    282173
    Location
    Long Island

    Question Catless Downpipe options

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    So I'm seeing all this talk about the EPL Stage 2 stuff that has just come out. I'd love to get my horsepower numbers up but I'm concerned with the factory cats. Coming from B5s I've seen people with catted exhausts have some issues with Heat soak and high EGTs. Now I know a lot of people are going to run the EPL Stage 2 stuff with the factory cats but I'd prefer not to so I was wondering what my options were?

  2. #2
    Veteran Member Four Rings christianb5s4's Avatar
    Join Date
    Aug 24 2014
    AZ Member #
    277489
    Location
    Newport Beach, CA

    What I'd do on these cars (this used to be a popular B5 S4 mod) is buy a second used set of downpipes and punch out the factory cats so it's like a 'piggie pipe'. Based on the design of the factory downpipes, it looks like a pretty straightforward process should you go that route.

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  3. #3
    Senior Member Two Rings
    Join Date
    Sep 12 2014
    AZ Member #
    282173
    Location
    Long Island

    I was thinking about that but noticed that usp sells miltek downpipes for B8 s4 that bolt to the exhaust manifold (unlike most other companies whose "downpipes" are just after the cats). They seem to be the proper shape for the c6 but I dont want to shell out $600 and then worry about return shipping and restocking fee if they dont fit

  4. #4
    Senior Member Three Rings dluxxx's Avatar
    Join Date
    Mar 13 2013
    AZ Member #
    111326
    My Garage
    2016 Porsche Cayenne Diesel
    Location
    Nor*Cal

    Quote Originally Posted by tmaclax013 View Post
    I was thinking about that but noticed that usp sells miltek downpipes for B8 s4 that bolt to the exhaust manifold (unlike most other companies whose "downpipes" are just after the cats). They seem to be the proper shape for the c6 but I dont want to shell out $600 and then worry about return shipping and restocking fee if they dont fit
    I've looked into this and contacted many companies and the design for the B8 S4 is totally different from the C6. The C6 design from the exhaust manifold back is C6 specific. I was thinking of just doing what christian said and just buy a second set and gut those.
    2010 A6 C6.5 3.0T, Remus Mufflers w/ Quad tips, Magnaflow Resonated X-Pipe, RocEuro Intake, EPL Stage 1, Transparent Gloss Copper Verde Axis V99 20x9, Michelin Pilot Sport 4S 265/30, Bilstein P14 PSS Coilover, H&R Rear Sway Bar, Ultra Racing Front Lower Brace, Ultra Racing Center Lower Brace, RS6 Black Gloss Grill, Rear diffuser, Black Vinyl window trim, Smoked Rear Tailights, Complete Interior LED Lights, Blacked out front sidemarkers, Morimoto 5000k D3S bulbs, SB3 Alpha Ceramic Coating.

  5. #5
    Senior Member Two Rings
    Join Date
    Sep 12 2014
    AZ Member #
    282173
    Location
    Long Island

    any idea how the car will react to gutted cats? I was curious about this considering it seems like theres only one set of O2 sensors instead of having front and rears

  6. #6
    Account Terminated Three Rings
    Join Date
    Feb 15 2018
    AZ Member #
    414102
    Location
    USA

    How tough is this job? I would like to roll around cat less when 24/7 when I am on the track and then when I go on the street to do emissions I will just put the cats back on.... I also don't want to blow my cats the way I drive

  7. #7
    Senior Member Two Rings
    Join Date
    Sep 12 2014
    AZ Member #
    282173
    Location
    Long Island

    Quote Originally Posted by NickLim View Post
    How tough is this job? I would like to roll around cat less when 24/7 when I am on the track and then when I go on the street to do emissions I will just put the cats back on.... I also don't want to blow my cats the way I drive
    My sentiments exactly, I'm more worried about the health of the motor (exhaust flow) rather than sound or anything else

  8. #8
    Veteran Member Four Rings MSq5's Avatar
    Join Date
    Feb 14 2017
    AZ Member #
    393251
    My Garage
    Toyota Highlander, Nissan Armada, Kubota M4030, Scag Tiger Cat 2
    Location
    Gulfport, MS

    If the cats are up high, right there at the headers, as on the S4 and my Q5, it may be a major challenge to get access to them. Not familiar with your setup, though.
    2017 Q5 3.0T S-Line | Brilliant Black | 034 Stage 2+dual pulley 93 octane tune | JHM 187mm crank pulley w/ EPL 57.6mm s/c pulley - 3.247 total ratio | Red Star shielded test pipes | Magnaflow high flow downstream ceramic core bottle cats | Vibrant Ultra Quiet Resos in place of OEM baby resos | aFe Pro 5R (part#10-10121) filter in "modified" stock air box | 034 silicone throttle body hose | HP Tuners custom TCU tuned ZF8 | Merc Racing HX | Michelin Pilot Sport A/S 3+ 255/45/20.

  9. #9
    Senior Member Two Rings
    Join Date
    Sep 12 2014
    AZ Member #
    282173
    Location
    Long Island

    Quote Originally Posted by MSq5 View Post
    If the cats are up high, right there at the headers, as on the S4 and my Q5, it may be a major challenge to get access to them. Not familiar with your setup, though.
    They up relatively high, on the vertical section of the downpipes, but not as high as B8 stuff from what I've seen

  10. #10
    Veteran Member Four Rings kneel's Avatar
    Join Date
    Dec 01 2007
    AZ Member #
    23014
    Location
    Orange County, NY 10918

    You could purchase the supersprint one for boat load of $$$$

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  11. #11
    Senior Member Two Rings
    Join Date
    Sep 12 2014
    AZ Member #
    282173
    Location
    Long Island

    Quote Originally Posted by kneel View Post
    You could purchase the supersprint one for boat load of $$$$

    Sent from my SM-G930V using Tapatalk
    Neil, I didnt see downpipe option on super sprints website. Not that I would buy them anyways because they are pretty spendy, but i wanted to take a look at what their setup is like with o2 bungs and flexpipes.

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