Cats

[silverhorse]

Reading with interest the various posts about downpipes and 200/100 cell cats and the benefits.
Can somebody answer a couple of questions for me please?

So, a factory cat is designed to capture and convert gasses to less harmful ones, this I understand. Being OE, it will be a compromise leaning more to emissions control rather than performance.
So when I read about a 200 or 100 cell cat, what does this actually mean? What is a cell? Surely a cat is a cat is a cat no matter how many cells it has? Is the only way of really unleashing more power to de-cat and getting rid of the restriction altogether?

[Harvey]

The 100 or 200 is holes per square inch, so a cat can have a face area of say 5-7 inch squared..

So a 100 cell cat has bigger holes for the gas to travel throught.

[don kalmar union]

Most standard cats are big and full of coated metal wool. They are made relatively cheaply that way and big because all manufacturers have to meet strict emission standards from a cold start.

100 and 200 cel cats are different and would not necessarily pass an MOT if tested from stone cold, nearly all cars are MOT tested with a warmish cat so that would cover any possible problems in that area.

Now how is one of these aftermarket cats made? Imagine a 6" strip of cardboard rolled up along a length of maybe 2 feet with the corrugations running across the 6" width, put to the eye you could see through its length. That is how one of these cats is made, replace the cardboard with corrugated metal sheet, then coat it with a so called substrate of the precious metal catalyst.

Maybe around 7/8 years ago the manufacturers of these items found a way of formulating the substrate in such a way as to need less surface exposed to the gasses to do the job. That actually made 100 cel cats cheaper for any given quality of catalytic material.

Now to quality and what you get for your money. Starting from the top a good quality stainless d'pipe will cost around £600, half of which will account just for the cat. So you just work out what you get for progressively less.....

And, a decat is a bloody antisocial and thoughtless mod., putting it bluntly.

Regards, Don.

PS. Ferrita use Finnish made Ecocat cats in their products, a company right at the very top of their game. you can read a bit here: http://www.ecocat.com/ they were formally called Kemira.

[claymore]

If a car with a decat can pass the MOT emissions test, then why is it antisocial?

[silverhorse]

And, a decat is a bloody antisocial and thoughtless mod., putting it bluntly.

Bit harsh.......!!??

[partsforvolvos.com]

my understanding is that most oe cats are ceramic on volvos, and certainly more so after 2001 because they must legally be hologomated to be allowed to be installed and it is harder to obtain this for a metal cat than a ceramic one.

regarding the 100 cel/200 cel thing, most cars with 2 lambda sensors would require a 200 cel cat to be sure of no problems especially given how much of a pain o2 sensors can be on volvos if you install anything other than oem parts.

[BoostWagon]

And, a decat is a bloody antisocial and thoughtless mod., putting it bluntly.

[stephenevans99]

I opted to de-cat my D5....I now realise I should've bought a Prius

[Harvey]

If a car with a decat can pass the MOT emissions test, then why is it antisocial?

I thought a car that had a cat fitted from the factory/new must have one fitted at its mot due to its age ?,vosa/gov rules.

Surely a car that should have a cat fitted can't pass a mot without one to get the numbers required as if it had one fitted from new.

Lastly when someone fits two engines to a car (can't think of anyone at the moment)what are the rules when going to the test station with such a car,(the rear engine is just ballast sir).

[claymore]

I thought a car that had a cat fitted from the factory/new must have one fitted at its mot due to its age ?,vosa/gov rules.

Surely a car that should have a cat fitted can't pass a mot without one to get the numbers required as if it had one fitted from new.

Lastly when someone fits two engines to a car (can't think of anyone at the moment)what are the rules when going to the test station with such a car,(the rear engine is just ballast sir).

If you have a mappable ecu, it's surprizing what you can do to the emissions, I have a map especially for mot time

[don kalmar union]

For real... maybe I could have been a touch more subtle ....

Don.

[graemewelch]

diesels dont have emision tests only smoke test.