I thought that I understood the regs but the more I read the more confusion reigns. As I understand my 2001 AJV6 engine definitely requires a CAT but the GOV website says that all engines from 01/01/2001 require a type approved CAT. At the same time most people seem to fit universal CAT's and get away with it. So what vis the correct solution that will get me through the test. If the engine had been built before 01/01/2001 then the universal CAT would be ok? I have been to a very helpful Jaguar dealer, my S type was first registered on 31/03/2001 and was assembled on 07/03/2001 but they were unable to get an engine assembly date, since these engines are a Ford variant has anyone had success with a Ford dealer?. All answers greatly appreciated

As long as it does its Job and the emissions are right I can't see anyone picking up on it. I've only ever used universal cats on everything from a Bec, a nearly new ecoboost and now the aj30.

I was really thinking along the same lines, although I have never had to replace a CAT for a MOT they did not notice that my new headlights were not E marked. When the time comes for the MOT I was going to take it to one where all the young lads in their Corsa's 106's etc go where they seem to turn a blind eye to such things. So which universal CAT do you buy, a cheapo Chinese one or a Magnaflow or Jetex, there is a huge difference in price, but the performance could be the same.

I tried a cheap Chinese cat and struggled at mot. On the fast idle test it wouldn’t flow. It backed up.

I then bought a Magnaflow at three times the price and found again you get what you pay for.

I used magna flow aswell. The only thing I noticed is they take a long time to get properly up to temp. I know all cats do to some extent but these more so. I drove 50 miles to iva and straight on to emissions test and it still took 2 attempts at the fast idle test (even after the tester wandered off and said just keep it revving) but then as they came up to temp the emissions dropped like a stone.

I used a 200cell metal monolith Cat, about £60 from ebay, got a carbed engine through IVA well under the 2002 limits.
I had to insulate it though.

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