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Discussion summary
YOUR RESEARCH996 Catalytic converter / MOT issue !
Leading reported evidence
Install by the previous owner
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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Performed · outcome unconfirmed
My '99 C4 has a full topgear exhaust - manifolds, 200 cell cats and boxes - installed by the previous owner.
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Suggestion
How TerraClean Engine Carbon Cleaning Works | DPF Cleaning
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Suggestion · Original poster
Car is a C4S, has a full Dansk sports exhaust set up - manifold, back boxes and sports cat (yes I'm waiting for the point the crappy joints will need replacing!), all put in by a previous owner - but, it does all sound epic.
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Suggestion · Original poster
Been researching options to replace the cat as near as stock spec as I can find, but not wanting an expensive Porsche one
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Suggestion
Trying some fuel treatment as suggested by others might be a good try before replacing expensive exhaust parts.
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Suggestion · Original poster
Car is a C4S, has a full Dansk sports exhaust set up - manifold, back boxes and sports cat (yes I'm waiting for the point the crappy joints will need replacing!), all put in by a previous owner - but, it does all sound epic.
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911uk: 1 discussions
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Hi all
Looking for some simple advice as having issues getting through an MOT on emissons.
Car is a C4S, has a full Dansk sports exhaust set up - manifold, back boxes and sports cat (yes I'm waiting for the point the crappy joints will need replacing!), all put in by a previous owner - but, it does all sound epic.
Car has just failed its exhaust emission on MOT, reading of 0.26 when needs to be below 0.2, despite being warmed up with a spirited drive beforehand
Been researching options to replace the cat as near as stock spec as I can find, but not wanting an expensive Porsche one
Best options look to be a DesignTek/Topgear 200 cell one, with oxygen sensor extensions added in
My Indy had a good look through the set up before the MOT, no leaks etc so we think its the sports cat causing the issue
Are there any other sensible options out there I may have missed, for a base standard cat?
Cheers
the sports cats are 200cell items i believe so should pass once hot really. I've passed 2 x Mot with DesignTek 200cell x pipe cats fitted, one of which was with the MOT tester getting assessed so differently a legit pass, cant help other wise.
worth trying an engine carbon clean as the carbon build up over time could result in higher emissions
Engine decarboniser 'Terraclean', has anyone done it??
Anyone tryed Engine Decarbonisation ? After watching wheeler dealers for the umpteenth time on Dave, i decided to have a look about for the Engine Decarbonisation system :thumbs: found a company called performancetuninguk whom offer it, sounds all very good, preventative maintenance and all...
911uk.com
How TerraClean Engine Carbon Cleaning Works | DPF Cleaning
Here is a simplified explanation of engine carbon cleaning, how it works and what it can achieve for your vehicle including increased mpg and efficiency
www.terraclean.co.uk
Terraclean – Zentrum Nottingham Porsche Specialist
Zentrum can offer Terraclean on your Porsche to boost performance and remove carbon from your engine.
www.zentrum.co.uk
Or just put a bottle of Cataclean in the fuel tank when half full and take it to the MOT with that in it. Works well at bringing emissions down if it's still in the fuel at the time of the test.
My '99 C4 has a full topgear exhaust - manifolds, 200 cell cats and boxes - installed by the previous owner. Had it 6 years, first year it failed lambda due to a small gap in one of the joints, not had an issue with it since. It's been to two different garages, neither have ever mentioned doing anything special to get it through.
MOT results from last month:
CO fast idle 0.02% (max 0.30%)
CO natural idle 0.15% (max 0.5%)
Trying some fuel treatment as suggested by others might be a good try before replacing expensive exhaust parts.
I second this. Mine grumbled through the last MOT with this, and even had a fault for the cat on the OBD2. I put the
Wynns Cat Cleaner
through and cleared the code. It has been clear ever since.
The trick with Cataclean is to leave it in the fuel, preferably with 1/4 tank of fuel in, at the time of the test. I run it through once or twice a year, but always tip a new bottle into a 1/4 tank for the test. A lot of these tend to be Kerosene based, but it does work.
