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3" cat back exhaust system

Discussion in 'A3/S3 Forum (8L Chassis)' started by Lizard-Racing, May 26, 2011.

  1. Lizard-Racing
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    Lizard-Racing DTM

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    Hi guys, looking at getting a 3" cat back system to replace my Milltek.

    What off the shelf options are there if any?

    What are people finding give the best performance increase?

    Alex
    #1
  2. superkarl
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    superkarl MAN OF STEEL

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    There is no 3 inch systema available off the shelf. Only custom. As for performance gains, there will be virtually none unless running a lot of power, and i mean a lot, . The likes of a milltek which is 2.75 inch is adequate on cars running over 350. as long as the back box flows well I think thats about it. Most performance increases will be from a 3inch downpipe and decat.
    #2
  3. S3Lol
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    S3Lol Member

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    Isn't the blueflame 3" off the shelf??

    No, wait, 3" DP to 2.75" for cat back.
    Last edited: May 27, 2011
    #3
  4. DenCar
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    DenCar Member

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    Im no expert on this but, i shouldnt think for the £-outlay on a new 3" cat-back system to replace your existing miltek wouldnt give you a great deal, if any performance increase. Maybe the miltek down-pipe and sport cat would be a better buy. But as i said, im no expert!

    DC
    #4
  5. nixy
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    nixy Member

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    as said would be a waste of time and money realisticly
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  6. Lizard-Racing
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    Lizard-Racing DTM

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    I am not running a 20v in my S3 so I need it to be able to flow considerably more, besides the Milltek is too heavy.
    #6
  7. superkarl
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    superkarl MAN OF STEEL

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    What engine/spec/power is it?
    If you are going for big power and numbers then perhaps full 3inch might be suitable.
    I've always wondered what the weight of a milltek is like.
    If you want it to flow more and be light then a similar design to the blueflame would be best, Obv with the bigger pipework, and just one straight can out the back, would be loud though.
    #7
  8. S3Lol
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    S3Lol Member

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    Can be a bit boomy from 70-80 on the motorway. fantastic exhaust though for performance IMO.
    Last edited: May 27, 2011
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  9. superkarl
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    superkarl MAN OF STEEL

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    Functional though lol, and not heavy and gay design like a milltek.
    #9
  10. Lizard-Racing
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    Lizard-Racing DTM

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    Im just trying something different engine wise, will be quite powerful hence starting the topic.

    Are the Blue Flames that loud then S1LFH?

    I dont think it will do a lot of miles and very few on the motorways etc.
    #10
  11. DenCar
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    DenCar Member

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    Your best option is a full custom made system to your own spec, and sell your miltek.

    DC
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  12. s3dave
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    s3dave TFSI Hybrid

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    Now now Karl...:p
    #12
  13. JamJay
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    JamJay Member

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    I thought I'd contribute here as I am one of the few 1.8T K04 owners running a full 3" system (3" DP, 3" Race-Cat, 3" Mid Section Non-resonated, 3" Straight-through Rear Silencer. I literally can't fault it, it does what I wanted it to and that was to chuck the gases out as fast as it possibly could with out being 'too' oversized. Since fitting it, it spools the turbo noticeably sooner and with no apparent loss in torque however my decision to use a non-res design with a straight-through, small cylindrical rear silencer has meant that it's pretty loud and racey sounding however, it just sound very nicely tuned, not chav. Motorway speeds cause it to hum but nothing ridiculous & during town driving it's pretty tame on light throttle, don't forget that there's a turbo-charger in the system which in itself acts as a silencer of sorts where as 3" on NA would be extremely loud. I assume you're going to be running a turbocharger? If not then you'd need an extremely highly powered NA to get any benefit with this as oversized piping would lead to massive back pressure loss.


    I chose a 3" system as I have always planned Hybrid or BT applications in the future and as this was my first upgraded Cat-Back, it was a no brainer to future proof the car if you like. If I had already paid £X for another system then I'd perhaps reconsider. My car is at approx 287bhp and this system works fine :).

    P.S. It's a custom system, no 3" options available off the shelf.
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  14. S3Lol
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    S3Lol Member

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    Blueflame is ok really, but does get a bit of a drone going between 70-80, which as a constant on the motorway, can get a bit annoying (IMO). What are you looking at doing? If you put it on here you will probably get some advice on if you are better off going with a 3" all the way through.
    #14
  15. Lizard-Racing
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    Lizard-Racing DTM

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    Thanks for input guys.

    Blue Flame looks a great set up but if its 70mm like the Jetex and Milltek stuff then it will not be large enough.

    JamJay I am interested to know where you had yours made and how much it cost.

    I will be making my own downpipe for this one and yes it will be turbocharged.
    #15
  16. Sam_
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    Sam_ Down under

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    R32 turbo? Like that crazy blue one :)
    #16
  17. Loupigs
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    Loupigs Member

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    So should I be keeping an eye out for your Miltek in classifieds then? :)
    #17
  18. a3rob
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    a3rob Member

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    Keep the miltek, its probably one of the best exhausts around. Love mine :)
    #18
  19. JamJay
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    JamJay Member

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    I had mine done by a LongLife centre in Carshalton, Surrey. I researched for weeks and these guys had amazing reviews in respect to their work. The whole system from DP to tail pipe is £700, would have cost less if it wasn't 3" all the way but then that's not what I wanted :).
    #19
  20. DenCar
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    DenCar Member

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    Agree, as iv said before, well tried and tested and excellent quality.

    DC
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  21. Lizard-Racing
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    Lizard-Racing DTM

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    The rear box is too heavy, and is there anyone on here running a Milltek with over 700hp, probably not even 400hp. What Im trying to say is that its tested yes but only to a point.
    #21
  22. DenCar
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    DenCar Member

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    Mines only 150 bhp with a map i will probably get around 200-220. The miltek is ideal for me and i will soon get the down pipe and sports cat. Im not running a formula 1 car so the weight of the back box is neither here nor there. However the weight of the miltek is a lot less than that of the oem, which now sits in my garage. Isnt the best route for you then a custom system made to your own spec?

    DC
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  23. JamJay
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    JamJay Member

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    The S3 system in comparison to the one they offer for the LCR is huge. Over on SCN, 90% all have Milltek and while it's better than OE, I think there's improvement to be made still. There's one guy who back to back tested Milltek vs free(er) flowing custom and the custom system made better torque and a few more BHP, this was on K03s though. I think there's just me & two other guys who decided to be brave & try something different, turns out to be a good decision & she's now GT30 proof (with new DP anyway). The build quality of Milltek is good, very good but that doesn't mean that a skilled custom fabricator cannot match or better it if the materials are of equal quality.
    #23
  24. Lizard-Racing
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    Lizard-Racing DTM

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    Yes I hear what you are saying, Custom will be the way to go it seems as there doesn't appear to be anything off the shelf. Thanks DC
    #24
  25. J B
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    J B Member

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    Lizard the powerflow in Basingstoke used to be pretty good, been a few years since I used them so not sure if they are still there now?
    #25
  26. Lizard-Racing
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    Lizard-Racing DTM

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    Thanks J B will look into it.
    #26
  27. JS1500
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    JS1500 Howdy

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    With 700bhp you should be looking to exit the exhaust underneath the car, within a Venturi Tunnel, to aid downforce!
    Titanium if you want it light too!
    #27

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