HFC:Any difference between 200 CPSI and 300 CPSI?
 

Is there any difference between 300 CPSI HFC and 200 CPSI HFC?
Which one better in WHP gains? :bowrofl:

Technical

"With its honeycomb construction, a monolith substrate consists of a number of relatively small “tubes” or cells through which exhaust gasses pass. The size of the cells and their length determines the amount of restriction and to some degree, the extent of catalyzing action.

...

Over the years, various brick densities have been used, with the most common now being 300 and 400 cells per square inch. All other dimensions being equal, converters with 100- or 200-cell densities offer improved air flow capacity, but reduced emissions control efficiency. In many cases, it's necessary to significantly lengthen a 100 cell converter to achieve the necessary levels of pollutant control. That additional length reduces flow capacity, so it's possible to end up with a 100-cell converter that does not flow as well as a 300-cell model."

CPSI is the density of the cells per square inch.
Cells are important, but you should consider the quantity of noble metals on the matrix too! That's what makes the cat expensive or cheap as Rhodium, Palladium and Platinum are not cheap.

I think the top brand is the German HJS, in the Fia GT, WRC and other international race champioship where the cats are compulsory they exclusively use HJS.

If the quantity of noble metal is insufficient you get CEL and you don't pass emission tests.

The diameter and lenght is important too...as with the same cells density if you have a larger cat you got more cells, obviously.