Audizine - An Automotive Enthusiast Community

Results 1 to 37 of 37
  1. #1
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Is this exhaust enough for stage 3?

    Guest-only advertisement. Register or Log In now!
    Hey, I'm hoping someone can chime in on my current exhaust setup and it's ability to handle my stage 3 build. I'm running RS6-R's, upgraded rods, SRM SMICs, fueling, etc...

    The exhaust came with the car when I bought it and I'm hoping it'll be enough for what I'm trying to do. I've got 3.5" DPs (not pictured) running into cats, tapering into twin 2.25" pipes, mating to a single 3" pipe (see below)

    Is this going to be a major bottleneck, enough so that I should upgrade the whole setup? If so what are your recommendations?





    Sent from my iPhone using Audizine

  2. #2
    Registered Member Two Rings Pik Masta's Avatar
    Join Date
    Apr 05 2017
    AZ Member #
    397106
    Location
    Houston Texas

    I think that 2.25 section might need to be addressed. I also think 3.5" DP are overkill since technically each turbo is flowing for 3 cylinders. just my opinion though.
    #JoyRideBiTurbo 2000 B5 S4 6MT Santorin/white leather Instagram: @PikMasta

  3. #3
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Two 2.25" pipes won't flow as much as a single 3" pipe? I would've thought the single 3" would be the bottleneck...


    Sent from my iPhone using Audizine

  4. #4
    Veteran Member Four Rings LINDW4LL's Avatar
    Join Date
    Dec 10 2011
    AZ Member #
    85071
    My Garage
    S4, E46 M3
    Location
    WI ✈ NC
    Items for Sale

    Quote Originally Posted by skree25 View Post
    I would've thought the single 3" would be the bottleneck...
    You are correct. A single 3" has 12% less area than a dual 2.25" system.
    -Hayden


  5. #5
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    ...but is it enough?


    Sent from my iPhone using Audizine

  6. #6
    Registered Member Two Rings Pik Masta's Avatar
    Join Date
    Apr 05 2017
    AZ Member #
    397106
    Location
    Houston Texas

    should be but i think it would be better to neck the down pipe to a SSAC twin 1 exhaust which has 2.5" dual piping.
    #JoyRideBiTurbo 2000 B5 S4 6MT Santorin/white leather Instagram: @PikMasta

  7. #7
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    How much power do you expect to make?

    a 3" rear section will be sufficient to at least 650whp depending on the type of muffler you have and how restrictive it is... you can gain some spool with larger primaries/downpipes, etc.

    It's an easy upgrade later on anyway.
    E36 DYNO TUNING WIRING PARTS

  8. #8
    Veteran Member Four Rings LINDW4LL's Avatar
    Join Date
    Dec 10 2011
    AZ Member #
    85071
    My Garage
    S4, E46 M3
    Location
    WI ✈ NC
    Items for Sale

    Quote Originally Posted by NOTORIOUS VR View Post
    a 3" rear section will be sufficient to at least 650whp depending on the type of muffler you have and how restrictive it is... you can gain some spool with larger primaries/downpipes, etc.
    Won't it hurt power to some degree, though, as compared to a dual 2.5" or 3.5" single setup?
    -Hayden


  9. #9
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by LINDW4LL View Post
    Won't it hurt power to some degree, though, as compared to a dual 2.5" or 3.5" single setup?
    I mean, it depends on how free flowing it is... People have made more than 700 on 3" turbo back setups, even more on 3" setups without any mufflers and short hood exits... In reality up till 600-650 a well designed high flow 3" setup will not hold you back at all from what I've seen. Especially not at RS6 size turbo setups on this platform.
    E36 DYNO TUNING WIRING PARTS

  10. #10
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Goal is 550 awhp. Are the cats less of a bottleneck than the 3 inch pipe or are they going to be a problem?


    Sent from my iPhone using Audizine

  11. #11
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    ...I guess I could always punch them out later if they were.


    Sent from my iPhone using Audizine

  12. #12
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by skree25 View Post
    Goal is 550 awhp. Are the cats less of a bottleneck than the 3 inch pipe or are they going to be a problem?


    Sent from my iPhone using Audizine
    Cat's will always be the biggest restriction certainly bigger than the other parts of your exhaust, unless you're running low cell count high dollar cats like GESI's for instance that are rated for big HP.

    That said, as always no exhaust is the best exhaust for turbo.
    E36 DYNO TUNING WIRING PARTS

  13. #13
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    So if I have any hope of making 550 awhp I better ditch the cats?


    Sent from my iPhone using Audizine

  14. #14
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Some data on the subject. Flow bench and street backpressure data.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  15. #15
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Quote Originally Posted by FlyboyS4 View Post
    Some data on the subject. Flow bench and street backpressure data.
    That's helpful, thanks. Though my exhaust is not stock and will definitely flow better...just how much better and whether it's enough is the question.

    Is there an easy way to tell if your exhaust is choking your engine?...besides a pressure test like the above link suggests. And if the pressure test is the only way, what pressure at what rpm would be considered too high...


    Sent from my iPhone using Audizine

  16. #16
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Both links also show results with 3" dp's and 034's single exhaust, those figures are probably more representative of what you could achieve.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  17. #17
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by skree25 View Post
    That's helpful, thanks. Though my exhaust is not stock and will definitely flow better...just how much better and whether it's enough is the question.

    Is there an easy way to tell if your exhaust is choking your engine?...besides a pressure test like the above link suggests. And if the pressure test is the only way, what pressure at what rpm would be considered too high...


    Sent from my iPhone using Audizine
    Only way to know for sure is to measure exhaust back pressure... otherwise you're just making an educated guess.

    In all honesty, you're worrying far too much about this for your target power level.
    E36 DYNO TUNING WIRING PARTS

  18. #18
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Quote Originally Posted by NOTORIOUS VR View Post
    Only way to know for sure is to measure exhaust back pressure... otherwise you're just making an educated guess.

    In all honesty, you're worrying far too much about this for your target power level.
    What about the cats though? I'm not worried about the single 3" but didn't you say that the cats would be a problem for the 550 awhp target?

    I need to install a wideband o2 and am debating adding a bung to the lower DP or deleting cats and rear o2 and installing it there. I'd like to keep cats if they aren't going to hold me back too much.


    Sent from my iPhone using Audizine

  19. #19
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    My results are using cats, I don't think a good set are going to hold you back.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  20. #20
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Quote Originally Posted by FlyboyS4 View Post
    My results are using cats, I don't think a good set are going to hold you back.
    Sorry I must have missed that you had cats in the link...answers my question perfectly then, thanks!!


    Sent from my iPhone using Audizine

  21. #21
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by skree25 View Post
    What about the cats though? I'm not worried about the single 3" but didn't you say that the cats would be a problem for the 550 awhp target?

    I need to install a wideband o2 and am debating adding a bung to the lower DP or deleting cats and rear o2 and installing it there. I'd like to keep cats if they aren't going to hold me back too much.


    Sent from my iPhone using Audizine
    Cats will ultimately hold you back of course... peak power at your level? maybe not, spool? for sure... again depends on how good your system is designed... only way to tell is measure back pressure...

    Flyboy doesn't really have a good example here as he's measuring on a 280awhp setup on K03's with a 3.5" 034 setup... I mean it really couldn't get more left field IMO.

    As I said previously.. the best exhaust is no exhaust on a turbo car.

    The more restrictions you add into the system after the turbocharger the more performance is lost. How much loss? no one will be able to tell you that until you perform measured tests on your setup.
    E36 DYNO TUNING WIRING PARTS

  22. #22
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Quote Originally Posted by NOTORIOUS VR View Post
    Flyboy doesn't really have a good example here as he's measuring on a 280awhp setup on K03's with a 3.5" 034 setup... I mean it really couldn't get more left field IMO.
    There's a little further in left field to go, that would be the place for the person who shows up to the discussion and brings nothing but an opinion and no measured results at all.

    Edit: Here is another measurement that also is not close to a 550whp setup.
    Last edited by FlyboyS4; 04-20-2017 at 08:23 PM.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  23. #23
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by FlyboyS4 View Post
    There's a little further in left field to go, that would be the place for the person who shows up to the discussion and brings nothing but an opinion and no measured results at all.

    Edit: Here is another measurement that also is not close to a 550whp setup.
    I"m not surprised a 034 3.5" exhaust system isn't restrictive at 400whp

    Also nothing I've said isn't true.
    E36 DYNO TUNING WIRING PARTS

  24. #24
    Established Member Two Rings WEBER's Avatar
    Join Date
    Jul 01 2008
    AZ Member #
    30480
    My Garage
    Imola B5 S4 , KTM Superduke
    Location
    Portland, OR

    So here's a little bit of real world exhaust comparison form yesterday.

    Stock block, RS6r's, SRM smic's, meth.

    With ssac 3-2.5 DP's to borla 3" single with stock midpipe couplers we could only squeeze out just under 400whp with out the car pulling timing.

    Fast forward to yesterday, only changes ARD 3" DP's to 3" mid pipes to 034 3.5" single, we were in the 440 range.

    So.....go big!!


    Sent from my iPhone using Tapatalk
    2001.5 S4 Imola

  25. #25
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Quote Originally Posted by NOTORIOUS VR View Post
    Also nothing I've said isn't true.
    According to you. Absent any evidence to support what you are saying the statements are your unproven opinions.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  26. #26
    Veteran Member Four Rings NOTORIOUS VR's Avatar
    Join Date
    Jan 29 2009
    AZ Member #
    38059
    Location
    Toronto

    Quote Originally Posted by FlyboyS4 View Post
    According to you. Absent any evidence to support what you are saying the statements are your unproven opinions.
    okay if you say so.
    E36 DYNO TUNING WIRING PARTS

  27. #27
    Veteran Member Three Rings
    Join Date
    Aug 30 2007
    AZ Member #
    20676
    Location
    nyc

    I wonder if most of the gains were from replacing the stock midpipes. I may be wring but I remember all the stock exhaust tubing looking very restrictive.
    c5 A6 tip
    this n that

  28. #28
    Veteran Member Four Rings 01audia4's Avatar
    Join Date
    Jan 31 2008
    AZ Member #
    24750
    Location
    Philly home of the cheesesteak
    Items for Sale

    Quote Originally Posted by WEBER View Post
    So here's a little bit of real world exhaust comparison form yesterday.

    Stock block, RS6r's, SRM smic's, meth.

    With ssac 3-2.5 DP's to borla 3" single with stock midpipe couplers we could only squeeze out just under 400whp with out the car pulling timing.

    Fast forward to yesterday, only changes ARD 3" DP's to 3" mid pipes to 034 3.5" single, we were in the 440 range.

    So.....go big!!


    Sent from my iPhone using Tapatalk
    Flyboy will say I have no data to back me up, I'm going to attribute this to the DPs more than the catback.

    Sent from my Nexus 6P using Tapatalk
    2001 A4 2.8-->1999 a4 1.8tq 220K-->2000 K04 S4--->2001 F21 S4 eating corn w/ stock rods

  29. #29
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Quote Originally Posted by 01audia4 View Post
    Flyboy will say I have no data to back me up, I'm going to attribute this to the DPs more than the catback.
    My guess is the exhaust contributes more than the DP's. In measuring stock (gutted) DP's and ASP's 3" there wasn't a huge difference, not like when the stock pre-cat is in place. The ssac's probably fall in between, but every piece makes a contribution.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  30. #30
    Established Member Two Rings milehighkid24's Avatar
    Join Date
    Oct 25 2013
    AZ Member #
    126830
    Location
    Aurora, Colorado

    For the power you want to make the exhaust needs to be addressed if your going from 3.5 inch dps into that tiny y to single piping through cats and 2 mufflers thats not ideal at all. I would delete the cats if you can in your state then if you really want to run a single exhaust all the way back I think you should do at least 3" piping and get rid of one of those mufflers. I run a similar setup on my RS6 K04 car (dual 3 inch all the way back from 3 inch DP's no cats and a single borla muffler) hope this helped

  31. #31
    Veteran Member Four Rings TighTT's Avatar
    Join Date
    Feb 21 2006
    AZ Member #
    10441
    My Garage
    one fast moped
    Location
    NJ/NYC

    Who makes 3.5 inch DP's?
    50% Blood
    50% Sweat
    50% Forced Induction
    Thats 150% motherf*cker.

  32. #32
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Quote Originally Posted by skree25 View Post
    Is this going to be a major bottleneck, enough so that I should upgrade the whole setup? If so what are your recommendations?
    I recommend you stick with the existing DP's and mid-pipe, assuming they are decent performance cats. Where the 3" piping starts to neck down have a 3.5" single setup made. Utilize a mid and/or rear muffler as desired.

    That's the setup I use. I kept the catalytic converters so as not to generate even more air pollution. I chose the 3.5" single for ease of fitment, dual 2.25" piping was tricker to align and have decent road clearance with. The 3.5" may also be slightly lighter, though I've not weighed the exhausts I have used, this is just a hunch. I chose to go with a mid and rear muffler for noise reduction. I've already posted the pressure measurements this setup generates. I'm not concerned about it keeping me from reaching mid-500 whp, I don't think that will happen. Yes I could delete stuff and get there more easily, but then there'd be some tradeoffs to make that I am unwilling to accept.
    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  33. #33
    Established Member Two Rings skree25's Avatar
    Join Date
    Dec 20 2014
    AZ Member #
    304549
    My Garage
    1999 Audi B5 A4 Avant, 1996 Cherokee, 1989 Honda VTR 250
    Location
    UT

    Thanks everyone for all the feedback and suggestions. Sounds like there's enough reason to just leave the exhaust in for now and see where it gets me.

    A twin 2.5 or single 3.5 is what would be ideal and where I'll likely end up.

    In all honesty I'm 3 months into this build and am just itching so bad to get it started up and in the road...


    Sent from my iPhone using Audizine

  34. #34
    Active Member Two Rings Xplycko's Avatar
    Join Date
    Jan 13 2017
    AZ Member #
    390557
    My Garage
    01 A6 2.7t 6 Speed, Nissan Xterra, Jeep CJ7
    Location
    East Tennessee

    Everyone has covered that it will no doubt hold the bhp you will be putting to the tarmac. I would suggest you at sometime do go to a single system and do away with the long y section. There's nothing wrong with a longer y section as it can help build low end torque but it needs to be done at the correct spacing to achieve the desired scavenging for this to happen. Some make light of exhaust companies charging more for their products because they are computer designed and flow tested. A 200 HP car wouldn't mind much, but when you start making serious horsepower it matters. Ask me how I know lol.

    Sent from my ALCATEL A564C using Audizine mobile app

  35. #35
    Veteran Member Four Rings
    Join Date
    Jan 06 2007
    AZ Member #
    14660
    My Garage
    '04 Mazdaspeed MX-5
    Location
    FL

    Quote Originally Posted by Xplycko View Post
    There's nothing wrong with a longer y section as it can help build low end torque but it needs to be done at the correct spacing to achieve the desired scavenging for this to happen.
    Could you clarify which Y you are referring to? The only one I am aware of is located after the turbochargers.

    Stock -> APR Stg1/2 -> GIAC Stg2 -> K04 -> 605 -> F4H -> K03 -> K04 -> F21MF -> TTE550 -> K04 -> TC Stg1 -> BW RS6 (On deck)
    MyAudiS4.com

  36. #36
    Active Member Two Rings Xplycko's Avatar
    Join Date
    Jan 13 2017
    AZ Member #
    390557
    My Garage
    01 A6 2.7t 6 Speed, Nissan Xterra, Jeep CJ7
    Location
    East Tennessee

    That's the one im talking about. The factory y pipe on these cars from what I have seen are more compact.

    Sent from my ALCATEL A564C using Audizine mobile app

  37. #37
    Active Member Two Rings Xplycko's Avatar
    Join Date
    Jan 13 2017
    AZ Member #
    390557
    My Garage
    01 A6 2.7t 6 Speed, Nissan Xterra, Jeep CJ7
    Location
    East Tennessee

    The pic above is a premade setup from an exhaust supplier correct? It looks different from your original pic post on the 1st page.

    Sent from my ALCATEL A564C using Audizine mobile app

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


    © 2001-2017 Audizine, Audizine.com, and Driverzines.com
    Audizine is an independently owned and operated automotive enthusiast community and news website.
    Audi and the Audi logo(s) are copyright/trademark Audi AG. Audizine is not endorsed by or affiliated with Audi AG.