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Reviews of 3 aftermarket catalytic converters

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by eljefino, Feb 7, 2020.

  1. eljefino

    eljefino Junior Member

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    All for the 2nd gen prius, all bought cheaply on ebay. No relationship with any vendors except as customer.

    First cat, bought from FITS: 2004-2009 Toyota Prius 1.5L CATALYTIC CONVERTER | eBay The Exhaust shop. Was $100, has gone up to $145 in the last month. Came with gasket, clamp, and hardware. I removed the RO2S, unbolted the original cat and sawzalled in the appropriate spot. Cleaned the graphite fake(?) asbestos gasket off the manifold connection. New gasket fit great. New hardware was junk. Bolt heads were too small to effectively capture the springs. Even though I thought I had them tight, I had a huge leak at the collector. Reusing the original bolts (15 years and in nice shape) fixed the leak. Aft slip joint pipe was inappropriately large. Best fix I could muster was to cut the joint off and use a 1.75 x 1.75 ID slip joint connector. OD of the pipe just before the resonator is 1.70" so I used muffler cement to fill the gap. Welded the forward connection off the car, used a 1.75" clamp on the aft one. Part came with a complimentary 2" clamp which I discarded. Deleted the emissions monitors, car passed them with the new part.

    Buoyed by this success (?) I had another car in need. Got this guy Catalytic Converter For 2004 2005 2006 2007 2008 2009 Toyota Prius 1.5L | eBay from Ontario Exhaust. Its collector gasket was comically huge so I reused the factory one which was still in good shape. Reused factory spring-bolts without even checking the new ones. Aft pipe was an unreasonably huge 2" OD that stretched to a 2" ID. Wound up getting a 2" ID to 1.75" ID reducer, welding its front, clamping its back with muffler cement. When the weather clears I'll see if the I/Ms click in. One year warranty. (EPA mandates 5 for aftermarket cats!)

    Third cat, as yet uninstalled, is from FITS: 2004-2009 TOYOTA PRIUS 1.5L CATALYTIC CONVERTER DIRECT FIT | eBay Arctic Exhaust. Its aft pipe is an honest 1.75" all the way down, so I'll just need a 1.75 ID slip joint connector. This also has the distinction of having been sprayed with silver spray paint. Five year warranty.

    Updates to follow! Point? Unlike most of the bottom feeding parts on ebay, these are not all from the same factory, supplier, or plans.
     
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  2. SFO

    SFO Senior Member

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    Thank you for the write up. Curious if any of the purchased offerings look similar to, or could pass as OEM?
     
  3. eljefino

    eljefino Junior Member

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    The OE cats are stamped GD3 and EA6. If you're in California these are unlikely to pass. They have adequate build quality and welding but don't look OE. And of course mine with their hose clamps have obviously been replaced.
     
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  4. eljefino

    eljefino Junior Member

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    Followup, all three are installed and passed internal OBD-II checks. Also, I had another it-looks-oversized header donut gasket and had to use it as my original was in poor shape. Said oversized gasket fit the pipe's "bell" properly and was cinched against the manifold flange by the spring-bolts. Doesn't leak. Seems a big gasket may not be a deal-breaker if that's what your unit comes with.

    The third cat, with its silver spray paint, smelled terrible while the paint burned off, for about ten minutes.
     
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  5. PriuscheaperTesla

    PriuscheaperTesla New Member

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    I just got my gen2 prius cat stolen under my car. Which one do you recommend on getting out of the 3? I am just going to take it to the shop for them to install it.
     
  6. oldtechaa

    oldtechaa Active Member

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    In San Francisco, unless you find a shop that's doing it illegally, none of these options are legal. Only an OEM cat is legal in California. You could buy an OEM cat and maybe save some money by taking it to an independent shop to install, but that'll save only a tiny fraction of the total cost.
     
  7. Capcraze

    Capcraze New Member

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    Anyone have an issue with the check engine light with an after market catalytic converter? Mine is coming off after a mechanic put the cheapest one he could find on. Also will it pass IL emissions?
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    The first thing you need to do is get the code read. I had a check engine light come on a day after installing an aftermarket cat. It was a Lean code and ended up just being the Mass Air Flow sensor needed cleaning.
     
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  9. DfLo1913

    DfLo1913 New Member

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    I just got my Cat stolen. If you had to Rank the 3, Which Cat would be Number 1?
     
  10. joe a.

    joe a. Junior Member

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    I have used both the Ontario Exhaust and Arctic Exhaust replacement cats and I live in Maryland. Both were acceptable replacements for the OEM cats, were ez to put in, and worked perfectly (including the 02 sensor) with no Prius issues such as warning lights. Would purchase either again.
     
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  11. pasadena_commut

    pasadena_commut Senior Member

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    As I understand it the reason the California Gen 2 catalytic converter is so valuable is that it contains more catalyst (platinum and other valuable metals). The reason it has that is that on a normal car the motor runs all the time and the unburned fuel keeps the catalytic converter at a high temperature where it is most efficient. On a Prius the motor is turning off frequently and so the cat on average does not stay as hot. To compensate for that they added the extra catalyst. I have not seen any evidence that the aftermarket cats contain the extra catalyst, so my guess is that they may not actually keep the car within CA emissions limits at all times under normal operation, like driving in stop and go traffic. The state knows this, and it isn't going to set up a special dyno, odd interval test for the car, so they just require the OEM part and call it a day.
     
  12. dolj

    dolj Senior Member

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    I think it is more the case that after-market manufacturers envisaged no market for quite some years and it was not worth the cost to get their catalytic converters certified for use in CARB states.
     
  13. ackermal

    ackermal Junior Member

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    Has anyone used a Walker Ultra Universal 93251 ? Its a SS/Ceramic Fed compliant universal aftermarket cat.
    Obv. not in the CA/ME/CO markets,
    We have emissions tests here in MD so I am envisioning I'd just need to run it nice and hot for a bit before pulling into the testing stall.
    Thoughts?