De-catting

[Raz316]

Im not sure where I heard this, but I understand cars made before a certain year don't actually have to be catted to pass their MOT. Is this true? Anyone know what year?

[Lemming]

Its true raz, aug92 I think. Do a quick search on ocuk, there was a thread about it recently in cars.

Having mine done on Tuesday, but as yours is a UK car I doubt you can remove yours and still pass emissions tests. You could remove and replace with a decat pipe and swap it back for the MOT tho, it seems some people do that on a regular basis.

[Raz316]

Cheers lemm0r, so does that mean cars made after aug92, have to have a cat regardless of whether they can pass the emissions tests without it or not?

[malfunction]

I'm not 100% on this but AFAIK you only have to pass the emissions test - you don't need a cat...

With the cat on you'll actually produce more CO2 IIRC...

[Moby-Dick]

What year is your car Raz ?

I'm lucky that none of the S13's ever needed to have cats on it ( though mine is 91 so I'm ok )

[Raz316]

1990

[Lemming]

take it off then raz , mine is 1990 as well so its off to stay on Tuesday.

[Moby-Dick]

Lemming - isn't your car an import anyway? in which case it never needed one as its sufficiently different to the uk model ( 3000GT ). I think its the same reason you can decat all MR2 Turbos.

[Raz316]

My MOT is in jan 2005, so I may as well

[Lemming]

Lemming - isn't your car an import anyway? in which case it never needed one as its sufficiently different to the uk model ( 3000GT ). I think its the same reason you can decat all MR2 Turbos.

Nope still cant decat realistically unless its before the cutoff date, hoping to sell mine to someone who still needs one for the MOT

[Russ]

you dont have to have a cat to pass MOT's, but u'll almost certainly fail emmisions.

[Jiff Lemon]

ok, the official stance used to be is this: (remember, I haven't practised as an MOT inspector since 2000, so things may have been simplified)

Cars made between L and M reg's had to be looked up on a chart - if you found a match based on chassis number, you did a cat test and the chart told you what range the emissions had to be within. If you couldn't find an exact match, then the car was tested on the old limits (Co < 3.5, HC<1200ppm)

From N reg onwards, you still consulted the chart, but if it wasn't on the chart, it had to pass a Default CAT test

The cat test itself is done at two separate rev ranges. One high (generally around 3000 rpm, but varies from manufacturer) and a second a tickover. The cars oil temperature is also measured to ensure the engine has reached operating temperature and the revs monitored by the cat testing machine.

[Lemming]

Took the cat out today, makes a little difference, though not as much as the induction kit did at the other end. Has added a nice rumble to the exhaust though

Next step is the rirdium plugs and magnacore wires sitting in the garage, away on hils for a week shortly but have three days off then before I go back to work so I'll see if I can convince the wife its necessary maintenance

Boost controller arrived this week from Japan and Nitrous is due end of this week these wont be fitted until the compression test and new A pillar trim so I can put a mechanical boost guage in to check how Im doing, unfortunately thats been delayed