rsrfan

Fabspeed has indicated they will be selling their own brand of headers with or without heat on the 6 speed forums. You guys heard anything?

JP

Chuck Jones

I would ask them if they're made here or if they're outsourced to our Chinese or Taiwanese friends. So many of the headers now are coming from outsourced manufacturers that they're pretty much all alike....it's just that some folks get more for their particular brand because of the brand name. Some of the guys who have been buying the cheaper stuff from eBay have been quite pleased with the results...and as cheap as they're selling them for, you could use them a couple years and toss them if they crapped out on you. My big concern would be loose slag from crappy welding in there that could eat your turbo wheels.

biglicks

you also want to make sure they have been put on a test jig after manufacture to ensure the downpipes are properly aligned. GSF do this although I have heard that the OBX versions on ebay are not.

Whoever you buy from, I agree with Chuck inspect for loose slag etc, I've recently ordered a pipe inspection camera for this purpose.

Steve

Metal Guru

The problem in the aftermarket header world is that austinetic stainless steels are utilized, which is the wrong choice for "hot" (considered to be from the engine to the cat) applications.
B & B and GSF make headers out of 304 stainless, which isn't suitable for the "hot" side of an exhaust system. SS 304 doesn't have good elevated temperature strength and poor corrosion resistance, especially in weld heat-affected zones. The "poor" corrosion resistance of 304 is due to carbide precipitation from the ferrite grains to the grain boundaries in the weld heat-affected zone. When a weld in SS 304 is exposed to a corrosive environment, corrosion in the heat-affected zone can cause cracking.
GHL manufactures headers from 321 stainless alloy. SS 321 is slightly better than 304 in elevated temperature strength but has an edge in corrosion resistance as it is a "stabilized" alloy. Carbides in 321 do not precipitate as readily from the ferrite grains to the grain boundaries as in a weld in 304, improving corrosion resistance. However, SS 321 is still mis-applied in the "hot" end of an exhaust system.
The preferred material for the "hot" end is ferritic stainless steels. Ferritic stainless grades have excellent elevated temperature strength and very good corrosion resistance. Many OEM's use ferritic stainless steel such as 409 for the "hot" end of an exhaust and 304 or 321 for "cold" end.

bucking

Metal Guru: if the manufacturers you mention do it wrong, at least from a materials perspective, who does it right?

Metal Guru

Bucking, both domestic and foreign OEMs have been using ferritic stainless for years.
I don't know why the aftermarket hasn't caught on....

RarlyL8

Cost.
There is a select group of customers willing to pay $2500 for a set of quality heat exchangers. There is a MUCH larger group willing to pay $500 and take their chances with fitment and quality.