cat converter

[woodwizzard]

Does the cat need to be "visualy" on the vehicle to pass and mot or does it have to register that it is doing its thing? Can the internals be cleared out to make it a straight through pipe, welded up and then put back on.

[BoxCleva]

My pick up has a straight through exhaust, and the cat has been removed.

The MOT guy said he would 'help' it through the test. He also said the emmissions were very close anyway and a service etc would probably sort it. He wasn't bothered that it wasn't there.

[woodwizzard]

I know some have gone through without but it does seem very garage dependant. Was thinking of taking it off and gutting it then welding it back up and re-fitting.

[BoxCleva]

Having a good relationship with a sensible tester is worth its weight in gold. I pay £54 for MOT's but he's fair and once spent an hour putting a tailbulb in a Multipla for me (horrid job) just so that he could write out the ticket.

[woodwizzard]

I have a similar relationship with the guys that I go to, they are quite happy to fit and adjust bulbs and fit wipers if needed etc. I suppose it comes down to whether the cat internals have much effect on the emissions readings.

[Drift]

Jim, its all down to the emmision and what the computer chucks out,

[woodwizzard]

Cat meets grinder then.

[Retro Pedro]

[Krusher]

Yes as Pete has already said above, I'm not quite sure of the year but the cat may not be tested

[RatCav]

A vehicle does not have to have a Cat ... however it does still need to pass the emissions test which will be difficult if the Cat is needed to lower the CO levels. Sometimes you can get away with it, sometimes you can't. Personally I would get a section made to replace it and get it tested (as in emissions tested) and figure out if you need it for the MOT.

And yes it is age dependant on the levels they test. My old Nissan 300ZX has no Cat and doesn't need the CO levels tested it seems so I got away with it.

"The catalyst test is part of the MOT test for most spark ignition petrol engined passenger cars with four or more wheels first used on and after 1 August 1992.
Carbon monoxide (CO), hydrocarbons (HC) and lambda (~) are checked at fast idle speed and carbon monoxide (CO) is checked again at idle speed.
The test should be self explanatory using the automated routine on 1996 specification exhaust gas analysers The following points should be borne in mind."

Extracted from section B1 from here.

http://www.motuk.co.uk/manual_730.htm

[jimmybhoy]

My old Nissan 300ZX has no Cat and doesn't need the CO levels tested it seems so I got away with it.
Meeez liking your vehicle choices Ratcav, My 300zx (avatar) has cats removed & straight through 3" stainless.

[RatCav]

Mine never had a Cat in the first place . Engine>Big Turbo>Pipe to the back with a small bax to make the sound nicer. I have the older Z31 Turbo manual.

Anyways I will stop before getting off topic ttoo much.

[red5]

Anything 'made' after Aug 1975/before Aug 1992 still gets CO and HC checked to 3.5%/1200ppm limits...even more off topic. Whoops.