as per my mate jim, who said this:

The information below came directly from the Vehicle Inspectorate Agency via email in response to a question I asked some time ago. The implications of the information for Sierra drivers are somewhat interesting and I've given some general advice over legal removal of the Cat at the bottom of this post.

If you want to take them and apply the information to Escrots or Festas then it's your choice but I'm specifically talking about Sierra's here so don't come crying to me if it doesn't work!


"For emission purposes vehicles are tested against details shown on the VIN and not the registration plate. Vehicles fitted with a different engine are tested according to which is older, engine or vehicle.

Catalytic convertors were introduced from 1st August 1992 and are compulsory after 1st August 1995. Vehicles first used between 01/08/92 and 31/07/95 are only cat tested if there is an exact match (re engine code) in the analyser database or in the Inservice Emissions book. Vehicles first used on or after 01/08/95 are cat tested using vehicle specific limits if there is an exact match. If there is no exact match it is cat tested using default limits, CO<=0.3%, HC<=200ppm"


Now the implication of this is that no Sierra is obliged to have a catalytic convertor as they were all built well before the 1st Aug 1995 date when cats became compulsary. Some late cars will have cat's as they were there only for Ford to be able to legally sell the surplus Sierra stock after 1st August 1992 prior to the arrival of the Mondy in dealerships.

But there is a small gotcha in the rules that depends on Ford's inability to keep accurate records throughout the 70's, 80's and early 90's. This is based on Ford passing accurate engine code data to the VIA.

And if you've ever been to a main dealer quoting the paint code from your VIN plate only to be told it's a completely different colour to what's on the car or that your VIN is not a known one (I have on more than one occasion yet no respray or "cut and shut" in sight!) then you know the chances of accuracy aren't all that good with relation to any "old" Ford!


So, if you want to ditch the cat I recommend you do a little investigation first. Just to be sure. This can apply to all cars, not just Sierra's but I'm thinking with Sierras in mind here.

Go and speak to your local MOT office - that is NOT the same as your local garage conducting MOT tests - The MOT office will be in your local phone book under "Vehicle Inspectorate" or something similar.

You need to ask them if your car's engine code appears in their emissions database.


If it doesn't or the match is only partial - you can throw your catalytic convertor away. Legally. The Cat emissions test cannot be used on your car, the normal 4% CO / 1200 ppm HC rules apply, and you can have great fun blowing raspberries at Mr. MOT tester next time he brings it up. You will need to keep all the Lambda sensors and stuff though, or your engine management could throw a tantrum, but the cat itself can be got rid of and a normal "non-cat" exhaust fitted to your downpipes.


If there is a complete match, you must retain the cat in theory. You could try removing the cat but even though your car isn't legally obliged to carry a catalytic convertor, they could test the car as if it is - even if built between those magical Aug 1992 and 31st July 1995 dates. And so your car could fail an emissions test. Now the MOT tester will be blowing raspberries at YOU!


hth