200 Cell cats - longevity

[Westy65]

I need to replace the cats on my Porsche Cayman 987.1 having just failed an MOT, badly, on emissions.

Porsche Tewkesbury have quoted me £4,972 for replacements, no that isn't a joke, which I will not be paying. However most other cats on the market are 200 cell cats and whilst I am sure I will appreciate the small increase in bhp, I wonder if this will be at the expense of longevity. Most seem to cost £1 - £1.5k or thereabouts which is much more reasonable.

So I would be interested to hear about any experiences with 200 cell cats in terms of how long they have lasted.

Thanks in advance.

[ingenieur]

I'd be wondering why your original ones went bad!

Oil or excess fuel coming from the engine? Just a thought.

Was the engine light on... as most modern cars can self-diagnose a faulty CAT using pre-and-post CAT lambda sensors.

You should be able to get a live reading on computer diagnostics to show pre-and-post lambda values which you can compare with manufacturers guidance to see if it really is failed converters. It might only be one failed converter as well.

[Westy65]

Thanks for reply. Ref last paragraph - is this something I can easily test at home? I should now only drive to a garage to get the car fixed.

[anonymous-user]

Technically it shouldnt have left Porsche Tewkesbury.

If it was diesel I'd recommend filling with HVO and it would sail through. With or without cats.

Have a chat with Lee at cps.

[Westy65]

It is Lee at Cotswold who is telling me I need new cats. Hence my original question on 200 cell cats.

[DodgyGeezer]

Not quite the same but I had 200 cell cats on my old SLK55 a few years ago at a cost of (something like) £150 with fitting extra. Still passed the mot and, IMO, sounded better (louder).

At that price differential you could replace them quite regularly and still be quids in...

[pits]

Mr Spoon said:

Technically it shouldnt have left Porsche Tewkesbury.

If it was diesel I'd recommend filling with HVO and it would sail through. With or without cats.

Have a chat with Lee at cps.

Why shouldn't it have left?

I would just go for the classic of kicking the st out of it before you get to the MOT

[cib24]

If you are worried about quality buy a 200 cell HJS catalytic a converter for the suited horsepower and get an exhaust shop to fab up the mid pipe if HJS or another supplier doesn’t make a direct fit pipe with their cat in it to buy off the shelf.

[Hereward]

pits said:

...I would just go for the classic of kicking the st out of it before you get to the MOT

Indeed. Italian tune up; get it red hot then immediately have the emissions test. My old Merc V12 always needs this treatment.

Edit: Plus a fresh tank of super unleaded.

For the sake of £40 take the car elsewhere for an MOT and present the exhaust good and hot.

Edited by Hereward on Saturday 20th August 10:42

[pits]

Hereward said:

pits said:

...I would just go for the classic of kicking the st out of it before you get to the MOT

Indeed. Italian tune up; get it red hot then immediately have the emissions test. My old Merc V12 always needs this treatment.

Edit: Plus a fresh tank of super unleaded.

For the sake of £40 take the car elsewhere for an MOT and present the exhaust good and hot.

Edited by Hereward on Saturday 20th August 10:42

If that doesn't work I find sometimes a crate of 24 Stella works in the boot, not sure what the MOT tester does with it, must pour it in the tank as it just disappears after the test has passed, weird.

[petop]

I have these 200cel cats on my Aston Martin Vantage.

https://www.enjukuracing.com/products/harrison-sig...

Only get them from US and they came to the UK via Afghanistan...long story!

Had them since 2015 and passes MOT every time and no issues.

[swanny71]

An option for you OP

http://www.carnewal.com/products/987/p87020/987-1-...

Exchange your old cat/manifolds for re manufactured units.
HJS cats are supposed to be excellent, Carnewal have a great reputation and a well established process for shipping etc.

[ingenieur]

Westy65 said:

Thanks for reply. Ref last paragraph - is this something I can easily test at home? I should now only drive to a garage to get the car fixed.

I'm not sure what sort of year your car is but from mid-naughties onwards many quality cars would have had multiple lambda sensors to be able to monitor the effectiveness of the catalytic converter.

If your car is so equipped then poor performance of the catalytic converter would 100% cause the engine light to come on. The ECU is able to measure the quality of the gas going in and the gas going out to check if the cat is working.

If you had something like Carly that might give you the live values from the sensors. I'm used to looking at this on the BMW ISTA system but I'm sure Porsche have their own equivalent which is just as sophisticated.

Essentially what I'm saying is if the engine light isn't on I'd be doing further checks before recommending the replacement of £4k worth of parts.

Might be worth getting a second opinion at another MOT station as I would expect the engine warning light to be on... dependant on your setup on your car of course... maybe it only has a pre-cat lambda.

Failing that... someone mentioned above the idea of getting an exhaust fabricator to install some generic catalytic converters rather than paying that astronomical amount for the Porsche parts. You could probably ask them what they would recommend.

[Westy65]

Yes the Carnewal cat is the one I’m looking at - I’ve also read good reviews about HJS. Still not cheap at €895 plus vat & import duties but still works out much cheaper than the Porsche OEM option.

[Rob_125]

As others have said, you need to be asking why your cats arnt working.

I had an e38 328, which used a hellish amount of oil (known issue for certain engines). And my mot tester managed to get it to pass, on original cats (although it did require a couple of enthusiastic attempts).

[Westy65]

The car is an 06 plate and has 4 lambda sensors with first in front of the cat I believe.

I’ve not had any warning lights at all so think the retest with the car good and hot is the best place to start, as suggested. Thanks

[Westy65]

So I followed the general advice and had the car retested when it was good and hot - failed again in the same way. See image:



Then I recalled that at the MOT in August 2021 it had taken a couple of attempts to get through, on omissions, and it got me thinking about that. So I wondered whether the remap I had done in April 2021 was the cause some how. I had done my research before I had this done and hadn't read about any issues of this nature.

Next stop was another independent car garage who spend an hour inspecting the car yesterday and couldn't find any stored faults, exhaust leaks, etc but did find that the fuel was running very rich - consistent with the MOT test he said. The recommendation before doing anything else was to restore the ECU to the original factory settings, which can be done if I get the company that did the remap in the first place involved. I've already spoken to them - their view is, perhaps not surprisingly, that it is nothing to do with the remap and it is likely to be failed cats, which of course it could be.

If the mixture has been running rich for some time I suppose I could have wrecked the cats by now due to excessive heat?

I was planning on having the ECU restored to the factory settings as this is the cheapest next step, but can't schedule this for a couple of weeks for a variety of reasons. I called my local Porsche dealer, Tewkesbury, to see if they could restore to factory settings - short answer is they wouldn't want to get involved with this.

Anyway, I would appreciate any views re any other options that perhaps I should consider.

Thanks in advance.

[mattyprice4004]

Hmmm, an interesting one - not too sure on the latest but just here to add that my 200 cell cat on my ZS180 is still fine 7 years and 40,000 miles down the line.
The KV6 is quite a clean engine, but with a single 200 cell doing the work that’d be done by 3 usually it can’t have an easy time!

[Westy65]

@mattyprice what brand 200 cell cats have you got?

[MIkey DSM]

Westy65 said:

So I followed the general advice and had the car retested when it was good and hot - failed again in the same way. See image:



Then I recalled that at the MOT in August 2021 it had taken a couple of attempts to get through, on omissions, and it got me thinking about that. So I wondered whether the remap I had done in April 2021 was the cause some how. I had done my research before I had this done and hadn't read about any issues of this nature.

Next stop was another independent car garage who spend an hour inspecting the car yesterday and couldn't find any stored faults, exhaust leaks, etc but did find that the fuel was running very rich - consistent with the MOT test he said. The recommendation before doing anything else was to restore the ECU to the original factory settings, which can be done if I get the company that did the remap in the first place involved. I've already spoken to them - their view is, perhaps not surprisingly, that it is nothing to do with the remap and it is likely to be failed cats, which of course it could be.

If the mixture has been running rich for some time I suppose I could have wrecked the cats by now due to excessive heat?

I was planning on having the ECU restored to the factory settings as this is the cheapest next step, but can't schedule this for a couple of weeks for a variety of reasons. I called my local Porsche dealer, Tewkesbury, to see if they could restore to factory settings - short answer is they wouldn't want to get involved with this.

Anyway, I would appreciate any views re any other options that perhaps I should consider.

Thanks in advance.

Sorry to revisit this post but did you ever find a solution to this. I am having similar issues and it would be very helpful if you found out if it was the Remap or the Cats that were the fault and how you fixed the issue?

Many thanks.