I have added a free flowing performance exhaust system to my car and was thinking about adding a high flow catalytic converter when I stumbled across someone selling ‘Metallic Substrate Catalytic Converters’. These are supposed to flow better and reach operating temperature quicker than convetional cats. They have ‘been used in europe for years’ - sounds like a late nite infomercial. The cost is almost twice that of a conventional high flow cat.
Are these for real? Will the give a performance increase?
I’ve heard of the metal cat cons. True, they do warm up faster and
have been used in Europe for years now, They have a drawback to the American ceramic substrate: metal melts.
Ceramics take much higher thermal stresses than alloys before faliure.
The main reason why cat cons weren’t put on diesels earlier was
because the high oxygen content of diesel exhaust would react ho hotly with the catalyst, even the contemporary ceramic monolith would burn up. Only the newer ceramics can withstand this temperature (approx. 2000 deg. F)
The car company I work for (Volvo) started using metalic cats in 1996. The metal cat is used in front of the regular ceramic cat.
The purpose of the metal pre-cat is starting working ASAP.
In a training session last year it was mentioned that in a 20 minute drive starting from cold that about 99% of the pollution from the tail pipe is in the first 30 seconds! The sooner you can get the cat working (needs about 540 F) the less crap out of the tailpipe.
Thank for the replies. These cats are now being marketed as a high performance replacement for a standard catilitic converter. Are they suitable for that purpose? Would they offer less restriction than a standard Cat? Would melting be a concern on a normal car?