How can i tell if i have 200 cell or 100 cell cats? Do i have to take them apart?

Second, is there a big difference performance wise between 100 cell and 200 cell?

 

usually they are stamped on the cats. more improtantly if your state requires smog tests then you should make sure any cat you have passes smog. for example here in California, if you change the cats you must have a CARB labelled cat in order to pass the visual test let alone the sniffer.

 

If the cats aren't stamped, you have to look at the matrix. 100 cell really means 100 cells per square inch. A 1" by 1" area will have 100 cells, so just count the number of cells along a 1" length. If you count 10, its 100 cell. If you count 14, its 200 (14 * 14 is about 200). This is a 100 cell:



A 100 cell has less stuff in the way of the exhaust flow, so it will be less restrictive than a 200 cell for a given cat diameter. Bear in mind that there are different diameter cats! The one about is a full 5" in diameter. Some aftermarket exhausts use smaller diameter cats, which will be more restrictive. Also, the metal that forms the corrugations can be thicker or thinner, depending on cat manufacturer.

Like most aftermarket parts, the "which is better" of cat options is not so simple!

Jeff