OEM exhaust manifold header material

[krashdumie05]

Anyone know what material the oem headers are made of? I’m going to cut out the cats out of the headers and weld in a straight section for a cheap set of Catless headers

[Slideways]

"All metal components in the entire exhaust system are made of high-temperature resistant austenitic stainless steel. Thanks to its high corrosion and acid resistance, the durability of the exhaust system has been extended to match the car’s life expectancy."

Some reading material - http://www.unofficialbmw.com/images/...ust_System.pdf

[PSUEng]

Ah, the Arvin Meritor presentation on the stock exhaust, great info in that. I will give it to AM for their engineering and I think the stock system is very good but, having my full SS V1, I have no regrets taking the stocker set off. And I do think the material selection would in fact result in the system lasting a long time. But damn, that section 3 is like 50lbs, no wonder the rubber mounts failed!

[timmo]

Wow! Indeed a great technical document, I wonder if any others exist for the E46?

[digger]

it doesn't appear to be 300 series maybe it is 200 series but still 308 filler material seems to be the recommendation for welding to 304

[bigjae46]

I think it’s a 409 stainless alloy. I think 308 wire will work. Should also back purge the weld.

Thats why you get the Megan Racing headers.

[digger]

I think it’s a 409 stainless alloy. I think 308 wire will work. Should also back purge the weld.

Thats why you get the Megan Racing headers.

409 is not austenitic so would conflict with the document above

[NZ_M3]

It’s 304 for non CSL