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Need Advice: Getting Downpipe to replace Pre-Cat

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    Need Advice: Getting Downpipe to replace Pre-Cat

    OKay guys I'm making the move to get rid of the pesky Pre-Cat. The shop I'm taking it too said making it'd be around $250. I told them I also need a bung to insert my O2 sensor.

    Does this sound right? Is it too high? Maybe someone knows of a downpipe that's already made to replace the pre-cat.

    I kinda need a quick response if you know anything.
    ED
    '05 6s 3.0L MT & '98 Pro DX 1.5L AT

    Mazda Enthusiast Club Member
    Click for my CarDomain page


    2nd Gen Protege Parts Catalog project in progress
    WTB: Gray 97/98 Protege Cupholder and Door Trim

    #2
    why bother?

    save your money and do something else to be honest.

    Unless the cat is giving you problems, I don't think removing it will give you that big of an improvement.
    photo album|photo album 2 (pbase)

    dbest1a AT yahoo DOT com

    Comment


      #3
      Thanxs guys.

      I'll see if this store can lower the price by a lot other wise I'll just go to another store. A catback for only 175 is really cheap though. Were you really cool with the guy.

      Yeah the pre-cat is giving me problems. The CEL is coming on. Error code: P0421 - Warm up Cat Efficiency
      Last edited by loganss; 10-02-2004, 01:49 PM.
      ED
      '05 6s 3.0L MT & '98 Pro DX 1.5L AT

      Mazda Enthusiast Club Member
      Click for my CarDomain page


      2nd Gen Protege Parts Catalog project in progress
      WTB: Gray 97/98 Protege Cupholder and Door Trim

      Comment


        #4
        Me thinks hes been reading the 3rd gen forums too much!

        (they do have quite an increase in hp with their precat removal)

        CLICK HERE FOR PICS
        1.8L 97 LX (CDN)
        Erebuni kit, JDM heads/corners/tails/hood scoop, 17" BSA 259 w/ Khumo Ecstas, KYB GR2 struts, Apex springs, Ractive X-drilled/slotted rotors, KVR C/F pads, EssentialSpeed CAI, Essentialspeed custom cat-back (y-piped with dual Vibrant mufflers), Clutch Masters clutch, touring wing, Vibrant F/R strut bar, AWR 21.5mm rear sway bar, indiglo gauges, Sparco wheel/shift knob, custom interior, TomMotorsports 'BRIDE' seats, Innovatek DVD-0181 DVD/CD/MP3/etc player, Innovatek IN-720 7" indash LCD, 'MZDASPD' plates

        Comment


          #5
          K Dawg , it's a 1.5 ... the only thing that will help the motor is either a 50 shot of nos or a nice T25 or t28 or T3..

          If he get's nitrous then I would say to look int getting some custom headers made. and opening up the exhaust.

          Sometimes I want to consider Nitrous on my 323, but I am not sure.
          photo album|photo album 2 (pbase)

          dbest1a AT yahoo DOT com

          Comment


            #6
            hmm, if you remove the cat... it is still possible that you're still going to have that check engine light

            because that o2 sensor will still be in your new pipe, and if you're getting a light for "cat efficiency" and you remove the cat... it will be even less efficient...
            unless im missing something here..

            Comment


              #7
              I ordered one of those chips that fools the O2 sensor into thinking it's working ok. That'll be my back-up.

              Either way the pre-cat is toast and I'm not paying a large amount of money to get a new one. And if the 1.8L can run fine with only 1 main cat so can the 1.5L.
              ED
              '05 6s 3.0L MT & '98 Pro DX 1.5L AT

              Mazda Enthusiast Club Member
              Click for my CarDomain page


              2nd Gen Protege Parts Catalog project in progress
              WTB: Gray 97/98 Protege Cupholder and Door Trim

              Comment


                #8
                Okay I replaced the Pre-cat and now the downpipe is in place. I took picks.

                As predicted the O2 is now giving an error code. 2 actually. P0135 - (Heated Oxygen Sensor Heater circuit fault - Bank No. 1) and P0134 - (O2 sensor circuit no activity detected Bank 1). This confirms that the Pre-cat was my problem.

                Car doesn't feel any different to me.

                Here are the pics:
                1
                2
                3
                4
                5
                Last edited by loganss; 10-06-2004, 04:33 PM.
                ED
                '05 6s 3.0L MT & '98 Pro DX 1.5L AT

                Mazda Enthusiast Club Member
                Click for my CarDomain page


                2nd Gen Protege Parts Catalog project in progress
                WTB: Gray 97/98 Protege Cupholder and Door Trim

                Comment


                  #9
                  BTW, did you remove the flex pipe? I could not make out much from the pictures.
                  "Probable impossibilities are to be preferred to improbable possibilities."

                  Comment


                    #10
                    Originally posted by turbonium959
                    BTW, did you remove the flex pipe? I could not make out much from the pictures.
                    I dunno where is the flex pipe supposed to go.

                    Oh and just in case anyone cares pic 5 looks totally different now. All the piping before and after my cat has been changed to 2 1/4" to match the catback. Catback pics r in my cardomainn page.
                    ED
                    '05 6s 3.0L MT & '98 Pro DX 1.5L AT

                    Mazda Enthusiast Club Member
                    Click for my CarDomain page


                    2nd Gen Protege Parts Catalog project in progress
                    WTB: Gray 97/98 Protege Cupholder and Door Trim

                    Comment


                      #11
                      Pre-cat

                      I thought about gut the pre-cat on mine 1.5L, but based on your statement (no difference in power) I think it is not worth. Can you talk a bit more about it ?


                      Thanks,


                      Originally posted by loganss
                      Okay I replaced the Pre-cat and now the downpipe is in place. I took picks.

                      As predicted the O2 is now giving an error code. 2 actually. P0135 - (Heated Oxygen Sensor Heater circuit fault - Bank No. 1) and P0134 - (O2 sensor circuit no activity detected Bank 1). This confirms that the Pre-cat was my problem.

                      Car doesn't feel any different to me.

                      Here are the pics:
                      1
                      2
                      3
                      4
                      5
                      Ex-nitrado, now only CAIdo

                      Comment


                        #12
                        Originally posted by marciobusi
                        I thought about gut the pre-cat on mine 1.5L, but based on your statement (no difference in power) I think it is not worth. Can you talk a bit more about it ?

                        Thanks,
                        Wouldn't gutting the precat make the flow of exhaust gases be more turbulent? Not sure how the gutting of a cat really works.

                        What did you want to know? Not sure I can help but I'll try.

                        I couldn't really feel an increase in power but that doesn't mean there wasn't. The main reason I did the downpipe was cause I was cheap. There's no way I was going to pay $300+ to get another pre-cat put on. Still passed emissions and car runs great (for a z5 auto 2nd gen).
                        ED
                        '05 6s 3.0L MT & '98 Pro DX 1.5L AT

                        Mazda Enthusiast Club Member
                        Click for my CarDomain page


                        2nd Gen Protege Parts Catalog project in progress
                        WTB: Gray 97/98 Protege Cupholder and Door Trim

                        Comment


                          #13
                          I am in teh same boat. My pre cat is getting bad. Eventually the light comes on showing bad pre cat. So sooner or later I will have to either buy one or gut that one. Like you, I will gut because its rediculous to pay 300 or more to a device that should cost less than 50 bucks to stimulate people to fight air polution.

                          If you gut, and add a pipe inside, the flow should become straight, and not turbulent. Even if turbulent, should be better than face that porous barrier.... Thats how I am thinking, maybe I am missing something here...
                          Ex-nitrado, now only CAIdo

                          Comment


                            #14
                            Loganss, from your pictures, I can't tell if you removed both cats, or just the pre-cat.

                            With one or both the cats missing, doesnt it stink **** up pretty badly?

                            My pre-cat is bad, I managed to cheat DEQ and passed, but in 2 years I dont know if Ill be able to do that again, need a permanent solution to this, down pipe looks pretty good, with an o2 sensor mod to fool the ECU.
                            '98 Protege (Sold at 125k miles)
                            2006 Mazda3S Grand Touring, Heated Black Leather, Moonroof, Bose 6CD, Tow package (LOL)

                            Comment


                              #15
                              Originally posted by skullone
                              Loganss, from your pictures, I can't tell if you removed both cats, or just the pre-cat.

                              With one or both the cats missing, doesnt it stink **** up pretty badly?

                              My pre-cat is bad, I managed to cheat DEQ and passed, but in 2 years I dont know if Ill be able to do that again, need a permanent solution to this, down pipe looks pretty good, with an o2 sensor mod to fool the ECU.
                              I still have a main cat and just removed the pre-cat. Still want to be street legal. I think my car smells like any other car, but my nose might not be too senstive to be able to tell the difference.

                              I don't have a way of knowing what the right values for the rear o2 sensor should be with the precat. If I know that it'd be pretty simple to create a solution to my catalyst below threshold error code.
                              ED
                              '05 6s 3.0L MT & '98 Pro DX 1.5L AT

                              Mazda Enthusiast Club Member
                              Click for my CarDomain page


                              2nd Gen Protege Parts Catalog project in progress
                              WTB: Gray 97/98 Protege Cupholder and Door Trim

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