Blown cats - What are my options

Twinspark

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I've recently had a look over on my car and it had a code P0132 relating to the O2 sensor, I took it to a mechanic who said that the cats are done.

While the secondary cats are not really a problem, assuming the worst and saying that all 4 cats are toast, what are my options realistically? I know that removing the primaries will trigger a CEL.

I have the GS which uses the newer style cats that are integrated into the manifold, a used pair is quite costly so I want to see what I can do. I've attached pictures of the setup on my car for clarification.7649276493
 

2b1ask1

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I’m working on it but don’t hold your breath... I doubt it will be soon enough for your needs.
 

TimR

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The best solution is convert the system to pre US style headers....and then fit cats in the section behind that to the x-pipe/ resonator. You only need one good (200 cell) cat each side. Keep it nearer the engine and it will maintain temps in the cats, and the lambdas reach no problem...***

*** apparently, the lambda loom needs redirecting to the rear of the engine bay for this....


Or, gut your headers and remake the second cat section with 200 cell cats each side...
Earlier manifolds are better from an exhausting/ engine tuning POV. Plus the US style have been known to fail and get sucked back into the motor, detonating that too....
 
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Twinspark

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I’m working on it but don’t hold your breath... I doubt it will be soon enough for your needs.
Depends on how “long” is long, I havent really been using the car and will likely not until early 2021.

Converting to euro headers is quite costly, finding the manifolds is easy but the center cat section is impossible to find, Larini might make a unit but I’d like to find a more cost effective solution.
 

2b1ask1

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Depends on how “long” is long, I havent really been using the car and will likely not until early 2021.

Converting to euro headers is quite costly, finding the manifolds is easy but the center cat section is impossible to find, Larini might make a unit but I’d like to find a more cost effective solution.

Well I'm commissioning a true specialist (as opposed to a tin pot back street joint) to create some headers and primary pipes that will address all the issues and short fallings of the present 4200/GS pipes including the location of the primary cats, the daft and stifling bends and squish! They will be single cats each bank located behind the steering rack but 5" 200 cell sports cats as opposed to the more common 3" or 4" people use which are still restrictive. The 5" are massively more expensive but worth the extra.

Now I just need to get to the top of his waiting list!
 

hladun

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149
You must really trust your mechanic to spend thousands on what may be a faulty O2 sensor.
 

Twinspark

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You must really trust your mechanic to spend thousands on what may be a faulty O2 sensor.
I'm already planning to remove the secondary cats. This is just a "worst case scenario" outlook so I can know whats the maximum amount I'd have to spend, I'd replace the O2 sensors first and see what happens from there.

Did anyone try the larini headers? What do they do that prevents the CEL from showing up?
 

TimR

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2,656
Didn’t catch anything about lambdas tbh but the earlier style has the bungs & primary cats below the headers he has... the part numbers for O2 sensors are the same for all cars so the wires will offer enough length to move them further from the block.
The problem with doing this is keeping temps high enough. Low temps mean they don’t perform as efficiently and they get sooted up ( lowering efficiency further still ).....all leading to MOT issues potentially.


I hadn’t realized that these header style, so-called US spec cats, were still ceramic. I thought they had the sense to move to metallic, less fragile cats... That is a potential worry. No wonder they break up & get sucked back into the combustion chambers....:oops:

@2b1ask1 ....Can I ask you to include me the loop on too..?
If my elusive motor tick is manifold in origin, I will need a solution. This might be ideal...:)
 

Zep

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the part numbers for O2 sensors are the same for all cars so the wires will offer enough length to move them further from the block.

There is a big but here. The wiring on US spec on the car runs with the loom to the radiator. If you go for euro type cats this cabling needs to be re-routed to allow the lambdas to connect.
 

2b1ask1

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Update; spoke to the man today and we are on the list with a view to a production pre-Christmas 20.

what are peoples view on ceramic coating the headers? Around a 30% reduction in temperatures around the manifolds and a bonus of hotter gasses at the cats. It is expensive but personally I feel it is worth it all day long.
 

Twinspark

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I’ve seen a lot of turbo cars use ceramic coating in their parts due to the heat but not as much on an NA car, I reckon it would help but not as much as it would on a turbo car.

Will the manifolds be in EU style or GranSport/US style?
 

2b1ask1

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US/GranSport style and flanges with heat shield mounts as per stock is the intention. They will be free flow and cat free with an O2 sensor mount on them for the pre-cat set. There will be another on the primary pipes after the sports cats.
 

TimR

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2,656
US/GranSport style and flanges with heat shield mounts as per stock is the intention. They will be free flow and cat free with an O2 sensor mount on them for the pre-cat set. There will be another on the primary pipes after the sports cats.

Do I take it that the second lambda reaches your proposed bung position behind the steering rack without faffing with loom routing then Newton?
I’m curious why you’d opt for us style headers at all really....!? Shorter individual lengths are t optimal. And if they don’t need to incorporate cats, and the cabling needs fettling in line with eu type layout anyway, I’m confused what drives your choice? Ground clearance maybe?
 
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TimR

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There is a big but here. The wiring on US spec on the car runs with the loom to the radiator. If you go for euro type cats this cabling needs to be re-routed to allow the lambdas to connect.

Good to know....:)
Is it a a lot of work Zep? Presumably you did this on Daryl’s car when swapping out his headers....
 

Zep

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Good to know....:)
Is it a a lot of work Zep? Presumably you did this on Daryl’s car when swapping out his headers....

I didn’t, but he did. You have to pull the cables back to allow them to go behind the engine. Not a huge amount of work but a bit of a faff.