Exhaust Catalytic Converter Requirements

[Adsy9]

Recently brought a 197 with almost a full years mot on it so I have time to consider.
I knew the car had a gravity system from manifold back but turns out this is a de cat system. It also has a Toyo/gravity manifold which removed the first cat? From the looks of it.
Which of the two is needed to pass emissions? I’m going to look at buying a standard cat to make the gravity system essentially a ‘cat back’
Any help is appreciated thanks!

 

[burrellbloke]

The OEM manifold has a pre-cat in it which was enough to get my car through MOTs on emissions without the main cat.

 

[Lawpf2001]

The OEM manifold has a pre-cat in it which was enough to get my car through MOTs on emissions without the main cat.

Assuming you have to take it in quite hot to pass?

 

[burrellbloke]

I have an Akropovic exhaust and when it was last tested by my local MOT garage, which usually find things to complain, about they were fine.

 

[RSRowe]

Just to throw the proverbial spanner, mine wouldn't pass with just the first cat, regardless of hot it got.

 

[VeiRoNv2]

This is mine with just the main cat,no cat in the manifold,it wasnt even fully warm so I would say the main cat is more than enough to pass,I dont unerstand why they put two of them either.

 

[Adsy9]

Thanks, looking like a main cat is on the cards then to make sure it’s passable at mot time.
Appreciate it!

 

[NickD]

https://clio197.net/threads/wheels-suspension-exhaust-and-bits.66809/

 

[Lawpf2001]

Just had my MOT done today, went to book in and they had a slot open at the time, so had it completed then and there. So car had driven 3 mins and left to idle for a bit.

It passed absolutely fine with a secondary decat and milltek exhaust. They actually did the test twice, once to see what results it would give, those results timed-out whilst actually conducting the MOT, so they had to redo emissions.

 

[VeiRoNv2]

That's right on the limit,that is with just the cat in the manifold correct?

 

[Lawpf2001]

That's right on the limit,that is with just the cat in the manifold correct?

Yep correct