ERZ Performance High Flow Cats, Install and Review Thread

[spearfish25]

Originally Posted by JoeyD

As i understand it 409 steel is stronger and resists temp better than 304. I could be wrong, don't feel like google-ing. Just saying different doesn't mean better or worse.

409 has a higher iron content and lower chromium content which makes it more likely to rust (at least surface rust). 304 is considered a higher grade of stainless, has lower amounts of iron, and higher chromium content. Just an aside tidbit, 316 is what is used in medical device implants. There is most definitely a better and worse between these, unless you say that the higher cost of 304 or 316 makes them worse than 409. Strength is really irrelevant when you're talking about exhausts...any of these stainless steels are stronger than aluminum which is often used and I hope no one's exhaust tubing is under any kind of severe loads.

Here is a site that talks about the two a bit:

http://www.usdieselparts.com/pages.cfm?ID=130