Catless downpipes - MOT time?

[Jfgoldfish]

Evening all,

What are peoples thoughts on whether a 2.0 Z4 will pass at MOT time with catless downpipes (secondary cat still in place)?

I am not trying to be a hooligan!!... I suspect there might be a small crack developing in my exhaust manifold and a new manifold is definitely out of the question. If there is in fact a crack, options would be to either get it welded up or buy a stainless manifold for from ebay for £150. Apparently the quality of the cheapish stainless ones is actually quite good.
I might just be being paranoid! I need to have a good look with an inspection mirror or smoke test it. Just preparing for the worst case.

 

[Jfgoldfish]

Nobody?

Do the euro spec cars pass emissions testing in the UK?
They have no primary cats. Only secondary.

 

[oldgitdave]

I've heard of the secondary cats being removed with no mot issues on the M54 3.0 but not just the primary ones. I think the Lambda sensors are just downstream of the primary cats. Maybe that would through an emissions fault if the upstream cats were not there. Just a thought I'm certainly no expert on this.

 

[Jfgoldfish]

Maybe that would through an emissions fault if the upstream cats were not there.

The O2 sensor downstream of the primary cats would need an extender or O2 emulator to stop the DME complaining that the cats are knackered.

I am very interested to hear if anybody has sailed through an emissions test without primary cats. My understanding is that they make little difference as long as the secondary cats are nice and hot.

 

[Z4-LV]

I have passed MOT without primary cats, only secondary in place

 

[Jfgoldfish]

I have passed MOT without primary cats, only secondary in place

Now thats the answer I wanted to hear!
Were the emisions well within limits?

I am tempted to pull the trigger on the stainless headers. Cheaper than even repairing the old headers.

 

[Z4-LV]

Now thats the answer I wanted to hear!
Were the emisions well within limits?

I am tempted to pull the trigger on the stainless headers. Cheaper than even repairing the old headers.
[/quote]

Yes, the emissions were in limits. You can see on pictures how looks the system, headers+ OE secondary cats+ supersprint Y-pipe +supersprint OO80 powerloop muffler.

 

[Rockhopper]

In theory a missing factory fitted cat should fail the MOT regardless of the emissions readings. MOT testers are aware of what should be there and should be looking for them. It’ll also be in breach of the Construction and Use regulations which is potentially a much more serious offence if the Police had occasion to stop you.
It’s up to you to weigh up the risks and the potential consequences

 

[Jfgoldfish]

In theory a missing factory fitted cat should fail the MOT regardless of the emissions readings

So that is another interesting point.
The first hit you get if you Google the question 'is it illegal to remove catalytic converter' is:

"It isn't illegal to remove a catalytic converter in the UK, but the car is unlikely to pass its annual road-worthiness (MoT) test if it's been removed."

So my understanding is that as long as you can still pass emissions, you are still within the law. Is that not the case?
Is there an MOT requirement for the exhaust to be stock? Surely ANY aftermarket system is a fail in that case.

Very confusing. Has the law changed recently regarding catalytic converters? :|

 

[mr wilks]

In theory a missing factory fitted cat should fail the MOT regardless of the emissions readings

So that is another interesting point.
The first hit you get if you Google the question 'is it illegal to remove catalytic converter' is:

"It isn't illegal to remove a catalytic converter in the UK, but the car is unlikely to pass its annual road-worthiness (MoT) test if it's been removed."

So my understanding is that as long as you can still pass emissions, you are still within the law. Is that not the case?
Is there an MOT requirement for the exhaust to be stock? Surely ANY aftermarket system is a fail in that case.

Very confusing. Has the law changed recently regarding catalytic converters? :|

I thought a visual check to see that all factory components regarding exhaust / emission was part of the mot :? removing the DPF is also a fail i believe but no idea how they could know that without doing some real delving which most MOT stations just don't get into .