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    Thread: Catalytic converter advice needed

    1. 11-17-2019 05:53 PM #1
      My cat is dying. This a Calfornia vehicle, so aftermarket cat options are limited. Installing a used cat is not legal but can be wangled.

      I see a Magnaflow cat that is CA-legal and wold like to know if anyone here has used either of those and what your experience was.

      Magnaflow 4481305
      2.25" in/out
      4" round body
      11" long

      Cost is $290. I wonder if at that price point there's little platinum but a lot of restriction.

      If you know of any other CA-legal aftermarket cat, please let me know. I was quoted about $1500 for an OE cat.
      1999 Jetta GLX VR6

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    3. Member
      Join Date
      Jan 4th, 2007
      2004 Jetta GLS 1.8T
      11-17-2019 06:53 PM #2
      OE. Cat is the way to go. It lasts for a long time. That price though for an OEM cat is insane. I assume that includes installation. The part in itself is around 1200 the last I had mine replaced.

    4. 11-18-2019 02:05 AM #3
      Rock Auto has a couple of C.A.R.B. compliant options that are much cheaper than OE:
      DAVICO 169818 for $465
      WALKER 81787 for $597

      These are complete bolt-in downpipes with cat included. In the long run this might be a cheaper and easier route than buying a universal and having it welded in.

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    6. Member xspeedracer's Avatar
      Join Date
      Sep 23rd, 2002
      2003/VW/GTI1.8T 91/VW/GTI VR6
      11-18-2019 09:45 PM #4
      So when you go in For a smog In ca they have to look at the cat for the BAR# EO# and it has to match with the allowed cats in the reference book
      Or check here https://ssl.arb.ca.gov/AftermarketParts/catalysts

      Sent from my iPad using Tapatalk
      2003 MK4 K&W V3 clubsport suspension, GC Camber plates, Shine Racing rear swaybar, 3"TB Forced-motion exhaust, Meistro Tuning, S3 strut bar, Baily DV, Modified Factory Airbox, VF engineering Motor mounts, TT front Brakes, H2Sport Control arms.
      1991 MK2 GTI with VR6 Conversion with a Vortec Super Charger, Bilstein Sport Suspension, 5 lug conversion, big brakes, Liguid to Air intercooler still a project car

    7. 11-19-2019 02:41 AM #5
      it's probably not your cat. Your flex pipes are leaking and air is getting sucked in from the atmosphere outside of the exhaust manifold exit. That is why your downstream sensor detects oxygen. I got 2x 1.5" flex pipes off ebay for $16 each and welded them into the downpipes rotten old flaky flex pipes... flex pipes are smaller in diameter but i didn't care as long as they're air tight..

      Once you take the downpipe down your going to want to make a form block out of two by fours w/ shims to connect the 2 y-pipe flanges pre-drill and screw together. Then cut one flex pipe at a time...
      Last edited by vwenthusiest1; 11-19-2019 at 02:49 AM.

    8. 11-19-2019 03:29 AM #6
      Thanks for the replies. So nobody has experience with the Magnaflow offering? I'll look into the other options also. Most importantly, I will make sure the flex pipes are not leaking before I replace the cat.
      1999 Jetta GLX VR6

    9. 11-21-2019 08:36 PM #7
      No state can ever dictate anything about catalytic converters.
      They stop salvage yards from selling them in CA, but any other state will sell them and it is perfectly legal.
      It also is perfectly legal to put any catalytic converter on as long as the results are sufficient.
      There is no visible markings on catalytic converts normally even to start with, and they rust quickly enough to make that pointless even if they did.
      But unless you hear the rattle of the porcelain matrix broken up, there is no reason to replace it.
      All you have to do is remove the residue that is coating the platinum, if the converter is not working right.
      That can easily be done with a torch. to burn off any coating.
      But bad oxygen sensors, air pump, diverter valve, bad EGR, or something else is far more likely.

    10. Member paramedick's Avatar
      Join Date
      Mar 12th, 2003
      Versailles, KY
      2015 Audi Q5
      11-21-2019 08:45 PM #8
      My $.02.

      If your cat converter is rotten, chances are your down pipe is pretty deteriorated.

      Link below is for a quality stainless steel down pipe with a catalytic converter option. Yes, it’s $600 total. However, you will NEVER have an issue with this downpipe or converter.


      I’ve installed a bunch of them. I’ve run them in my own vehicles.

      Good luck.

    11. Member KiDGiB's Avatar
      Join Date
      Jan 28th, 2013
      11-21-2019 09:32 PM #9
      If it's CARB compliant and the numbers match, there should be no problems.

      These links can probably help with the information you're looking for to make up your mind.

      I can't fully answer your question, but I am running the MagnaFlow 59959 Non-Carb compliant cat and it works great.

    12. Member BassNotes's Avatar
      Join Date
      Mar 15th, 2005
      Santa Ana, Calif., USA
      2002 VW GTI 1.8t
      11-21-2019 09:43 PM #10
      When the cat on my GTI 1.8T was getting weak about 10 years ago I bought a used OE one from another Vortexer who had one cluttering his garage. I had it installed and had no problems passing smog since. I don't think that approach is illegal.
      Bob Lee
      2002 GTI 1.8t 297,000+ miles
      VCDS 18.2 with KEY-USB interface

    13. 11-21-2019 10:23 PM #11
      I have a 14 Passat and I installed the CTS downpipe with a Magnaflow high flow cat on it. I also added a spacer and have not had a check engine light. Not sure what year the cut off is but on newer vehicles in CA, they just hook the SMOG machine to the OBD port to make sure there are no check engine lights. If your car is just the OBD test and not the sniffer, you can get away with the SMOG check as long as there is no light.

    14. 11-21-2019 10:25 PM #12
      And another thing. I have never had a CA smog check where the tech checked underneath the car to match up the CARB # on a CAT to a database.

    15. Junior Member
      Join Date
      Aug 29th, 2005
      06 Jetta 2.0T package 3 and 05GolfGLS TDI Tip
      11-21-2019 11:34 PM #13
      I have had some luck with this GERMAN made gas additive called OXICAT that clears up carbon buildup in cat converters
      Bob Guttenberg IC1
      USS Yorktown CVS-10
      USS Bainbridge DLG(N)-25
      Following winds and cheap diesel

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