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  • Decat done today - not very impressed

    Had my decat done today.

    Some of you will remember that I went to a local place that makes custom stainless exhausts and asked for a single 2.5" straight through decat pipe. I took the car in this morning and said again what I wanted. The guy seemed a bit distracted but I did say what I wanted. When I picked it up I got this............ (see below)

    I asked the bloke why he hadn't done the single pipe and he looked dead blank and said that it did the same thing.


    It is 2.25" in the front braches and 2.5" in the straight and blows like crazy from the rear joint. I told him it sounded like it was blowing when he backed the car out but he said it just sounded louder as the CATs had gone. But believe me it is blowing like mad, it even pos and splutters sometimes.

    I cant see how the Y section gives good flow but he assures me that it does. And worst of all the car seems to have lost loads of its low down torque. Maybe its just psychological but it feels really gutless at low revs and to me that’s one of the things I really loved about the car!!

    So I'll be going back tomorrow to get the blowing sorted out, any reason why it should feel less torquey?

    See next post for another pic. (‘cause I can’t work out how to attach 2 to this post)

    I welcome your comments:confused:

    Leigh
    Attached Files
    Ex 1994 Avant - now driving a Lotus 340r

  • #2
    Another picture of the decat 'thing'...........
    Attached Files
    Ex 1994 Avant - now driving a Lotus 340r

    Comment


    • #3
      I've already told to people that you will loose some torgue on low rpms and gain on high. Becouse of back pressure. But yeah everybody laught.

      Mettalic sound can appear after removing CAT.

      Strange that they couldn't install 1 strainght pipe , but sometimes it require to rebuilt downpipe to do so. I've seen once.

      ****** sound , eh , yep it is.

      And yes about Y pipe. Every turn or new join will not help for gas to flow better. The less joints the better.

      P.S. Holy crap my english sucks.
      Vadim.

      New engine (mechanical PKM head) , Alcon 332mm brakes , Pauter rods , Mahle pistons, GT30R , kw v2 sucpension , new exhaust. 608HP. For SALE !

      Comment


      • #4
        Leigh,

        I recently got my SS exhaust fixed - it was blowing at a join to the centre box - it wasn't really noticeable(audible) at idle but when it was on the ramps and revved it opened up! I found it made a huge difference to the way it felt - it felt torquier when it was all fixed - Get the joints to mate properly - try and get him not to plaster it is putty.

        HTH
        S2,RS2,S4 WB,RS4,S4 B8,RS6 C5,RS6 C6,R8

        Comment


        • #5
          Doug

          Thanks for the advice. It is blowing really badly, sounds awful and you can feel it if you put your hand up to it.

          Also I seem to remeber my CATs having heat guards above them which don't seem to be on there now (see picture) am I remembering rightly?

          If so they better not have thrown them away as something tells me they will be expensive :mad:

          Leigh
          Ex 1994 Avant - now driving a Lotus 340r

          Comment


          • #6
            Yeah. There should be shielding. The same as for mufler. But I believe they are only needed for cat's and muflers becouse after stoping the flow they recieve a lot of heat energy.

            Dunno if they are expensive. Better to ask Martyn.
            Vadim.

            New engine (mechanical PKM head) , Alcon 332mm brakes , Pauter rods , Mahle pistons, GT30R , kw v2 sucpension , new exhaust. 608HP. For SALE !

            Comment


            • #7
              Gr8 - can't wait to see what the garage has done to mine now (honeycombs knocked out of cats) - bet this 1.0 litre polo will be faster :S

              The old exhaust was blowing in so many places though that the new one HAS to make a difference. Better fookn do at £500 for the damn thing. Oh well, at worst it won't look like it's going to fall off at any moment.

              :confused:

              Will give you a call Leigh when I get the car back - we can suck through our teeth, rub our chins and shake our heads at each others cars.
              'The Bacofoil Express'...

              No more.

              Leon TDI 150 run in now.

              Very slow.

              Needs a chip.

              Comment


              • #8
                The lack of torque low down is NOT from having the CATs removed - its because the ****** thing is leaking. Such leaks really upset the flow of exhaust gas across the turbo. Get it sorted and I'll bet it feels better...

                However - it sucks that they didn't fabricate a single St.thru pipe - was there a reason why they kept the 2:1 pieces ?


                Paul
                Paul Nugent
                Webmaster http://S2central.net
                Administrator http://S2forum.com

                1994 S2 Coupe ABY - aka Project Lazarus
                2001 A6 allroad 2.5TDi - family tank
                2003 S4 Avant 4.2 V8 - daily burble

                Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                There are only 10 kinds of people that understand binary - those that do, and those that don't

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                • #9
                  Paul

                  The only reason that they kept the 2 into 1 is because they didn't listen to me! When I took it in he sais 'oh yeah a Y piece' to whcih I said 'no we discussed a single pipe and getting rid of all the 2 into 1 stuff' :mad:

                  I thought the customer was always right.

                  I'm taking it back at lunchtime to get the leak fixed and then hopefully on somewhere to get an emissions test.

                  I'll report back.

                  Leigh
                  Ex 1994 Avant - now driving a Lotus 340r

                  Comment


                  • #10
                    Just wondering if you had any luck with the de-cat pipes?

                    I would like to add my experience - I had a Scorpion Stainless Steel system, but originally retained the Cats. The Scorpion Cat-replacement pipes went on recently and made quite a difference I thought. It is slightly less torquey at the bottom end but definitely freer at the top end. The noise it makes now though is much better and occassionally I get flames on the overrun
                    Ex S2 owner, now running around in an A4 Avant quattro...

                    Comment


                    • #11
                      When decatted my car was a bit louder and I reckon it lost a tiny bit of low down torque.

                      Now the CATs are back on it is definatley quieter.

                      Leigh
                      Ex 1994 Avant - now driving a Lotus 340r

                      Comment


                      • #12
                        What a crappy job m8! Get them to use formed bends for a start as you are loosing diameter on the bends!! Also your front pipe has the y split built in, my 3b had a seperate part for the split which now belongs the Zorro along with the rest of the exhaust system. This would make it harder for them to get rid of it. But if you asked for a straight pipe then that is what you should have. Tell them about the trade descriptions act!!
                        sigpic
                        Tom C - www.rcmr.co.uk
                        Audi UR Quattro
                        Audi 100 C3 2.0 5 cyl 115ps
                        Audi S2 - 07k engine project aiming for 800ps
                        Audi B5 RS4 645ps 911nm

                        Comment


                        • #13
                          You said it Tom!

                          Took it back 'cause it was blowing and they fixed that. When I came to take the pipe off I found that they fixed it by stuffing it full of exhaust paste stuff :mad:. Basically I will never use them again and tell everyone how **** they are. I had heard really good things

                          My ABY downpipe and splitter is all one pice (I think) maybe I should get a 3b one is it has a separte part. Then I could get a single straight though pipe done properly. A 3B downpipe would fit?

                          For now I'll keep the CATs on, until my mystery smoke comes back, if it ever does
                          Ex 1994 Avant - now driving a Lotus 340r

                          Comment


                          • #14
                            I dont see a reason why a 3b one wont fit? Mine had a new one in '96, cost a fortune new. Something like 150 quid plus VAT, back then!!

                            Martyn and Paul, you can answer these questions, will it fit and how much??
                            sigpic
                            Tom C - www.rcmr.co.uk
                            Audi UR Quattro
                            Audi 100 C3 2.0 5 cyl 115ps
                            Audi S2 - 07k engine project aiming for 800ps
                            Audi B5 RS4 645ps 911nm

                            Comment


                            • #15
                              Using the 3B downpipe and then 3B splitter on the ABY?

                              I'm not so sure it will fit to be honest... The 3B d/p will fit up to the turbo and WG, but my concern is the splitter and also the diameter's of the 3B / ABY. I have a feeling the 3B DP has larger diameter flanges, then also, isn't the 3B splitter quite a lot narrower than an ABY splitter??? maybe because of the gearbox????

                              Need to get two cars next to each other...
                              3B DP: £163+
                              Splitter £80+
                              Last edited by Martynf; 8 September 2003, 22:27.
                              Martyn
                              -------------------------------------

                              www.vagparts.com

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