19 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHBad Cat... Failed Inspection
Leading reported evidence
Install davico cat
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
Unsuccessful attempts
1
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Leading evidence: 'Install davico cat' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check engine code indicating a failing catalytic converter' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
(even changed the air oil separator though that was likely only tangentially related) .
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed
When one of my cats died I replaced both with NHP's 200 cell crossover cats.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
19 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T152433Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I have been struggling with a Bank 2 P0430 check engine code indicating a failing catalytic converter. Changed the 02 sensor. (even changed the air oil separator though that was likely only tangentially related) . Ran a treatment in the gas. Reset the code a bunch of times. But all to no avail. So, I am sucking it up and buying a cat. Being a cheap son of a gun, I am trying the Davico cat.
https://www.rockauto.com/en/moreinfo...388314&jsn=375
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Looks like it will fit exactly. Hoping it cures the problem. Anyone else use one of these?
I had a p0420 cel code. After trying the Techron treatment unsuccessfully I found replacement MagnaFlow cats at Summitt Racing. I got the CARB 50 state version for about $1,150 for both cats. I needed to call to get MagnaFlow to get them send me the couplings, which they did free of charge (they come automatically with the 49 state version, go figure), and then my indie installed them. After about 1000 miles everything is running well with no cel. I’ll post status again in another few thousand miles.
I have these on my '99 along with their headers and stock mufflers with bypass modification. I replaced all 4 O2 at the same time. No cels in over 1000 miles so far.
https://www.topgear-usa.net/porsche-...ll-sports-cats
IIRC under $600 shipped and took only a week from the UK. Very nice quality too.
another happy/satisfied Magnaflow guy here....gets the job done for way cheaper than OEM, guaranteed pass with Nazifornia emissions and last but not least, proven track record of Magnaflows
I looked at used cats, but the cost for a used cat of uncertain history is often $400 or more. So, for $217, I thought I would give the Davico a try. We'll see if fitment is good and if the light stays out!
@kromdom or others, any suggested performance gains from the Magnaflow cats? Also considering these here in sunny CA, as they seem to be best bet for a CARB compliant retrofit without the full expense of OEM. If any improvement to the wheels, even better. Thanks
My "butt dyno" did not notice any performance gains (nor did I expect any in the first place). My main priority was a "cheaper" option that will pass SMOG (including visual inspection).
Aftermarket cats will almost always pass a smog test and do very well. They just don�t last as long as OEM in most cases. It�s a trade off I am usually willing to live with.
Damn, that's a great price. Keep us updated. Interesting thing about these is that they look more like a stock cat, no shiny metal or welded on badges. Wonder if they would pass visual in CA?
When one of my cats died I replaced both with NHP's 200 cell crossover cats. More than these cost for sure, but still a pretty great deal considering. But there is no way they'd pass visual in a place that requires OEM. Had them on for 30k miles with no problems, passed emissions every time. Pulled them off last week when test fitting a catless x-pipe and they were still in great shape with no corrosion. Just some color change as one would expect.
I now have over 2,000 miles on my MagnaFlow cats. Still no CEL. Looking good.
I forgot to mention in my previous post that they’re warranted for 5 years or 50,000 miles if professionally installed, including for California.
Installed the Davico cat today. Hardest part was was getting off the three nuts connecting the cat to the header. They were all welded on with corrosion. We ended up cutting them off. After that it was easy. The part looks stock with a slightly smaller cat section. So far so good on the CEL, though it is pretty early... only about 20 miles so far.
Today, after about 200 miles since the change, the car passed New York State inspection. No check engine light code. No drivability problems. The Davico cat looks pretty much stock and if I had also changed the other side, one would never know something was different. 02 sensors show normal operation for the new cat (and a good deal better than the remaining OEM side). Count this project as a success.
This may be a long shot but have you checked to be sure the O2 sensors are connected correctly. They should be color coded st the connectors, black and gray. They should be plugs for the wiring harness should be color coded also.
If the car is only getting 10-12 mpg, it is running extremely rich and all the extra gas will wash the oil off the cylinder walls and they will score. Not to mention the oil dilution from all the excess gas. At this level of oil dilution I would change the oil much more often than every 5,000 miles. The upstream cats control the mixture and the downstream cats serve as a monitor for the function of the cats. The pre cat O2 sensors are the ones that need to function, the post cat O2 sensors are to monitor the cats function and don’t have any control over the fuel mixture.
You need to correct the mixture issue before putting many miles on it.
Good luck with it.
Mark
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