[thumbster]

Originally Posted by LSKustumz

If you are complaining about cost of the headers now at $600 which is far cheaper than any other competitor, which there is not any. But 321 steel will expand and contract differently than the metal on the head and cause leaks, crack welds and jump the cost up A LOT. If you have not seen the raw material cost of stainless lately than you are assuming too much. As I have said before, I'll say it again, other metals are just not suited for the application. So if you think $600 for mild steel now is a lot, make them 321 and see the price up to $900-1000!! Everything will have to be tig welded, and will be much more brittle and susceptible to corrosion. Nothing worth a GOOD amount horsepower will not be easy. This goes for anything. Our headers combined with an intake and exhaust is the best bang for buck horsepower you can get!!

I like the design of these headers, BUT....

If welded correctly (tig or mig), 409 is superior in durability to mild steel and will therefor handle more heat due to it's higher carbon content. It is the material of choice for heavy duty truck exhaust systems because of this durability. How do I know this? I have been tig/mig welding custom exhaust systems on airplanes, cars and boats for 20 years and have never had a weld fail on any header or exhaust component, even on a turbo application - period. It all depends on the filler material, welding technique used, and you have to back shield the inside of the tubing when you weld it. One of the main reasons toyota had problems with the older tundra's manifolds were the way they were welded - welds were done way too hot for the sake of production speed, causing them to crack right at the tube flanges on the heads. Expansion rates only matter when you use dissimilar metals for your flanges and tubing. Most header manufcaturers use mild steel flanges even though they use 409 or 304 stainless tubing. Inconel (321) is obviously cost prohibitive and totally overkill on a street vehicle, hence the in my last post.

Even the best coatings will eventually wear off in time, so using stainless steel of any grade will at least keep the whole thing from rusting apart prematurely. Like I said before, since the labor costs for installation will be high, I would like know they won't rust apart when the coating eventually fails. Mild steel is only used in exhaust systems for one sole reason - cost reduction.

When the internal coating fails (which you can't see from the outside) you will have surface rust on the inside of the header. This iron oxide can contaminate the O2 sensors causing them to fail prematurely. Even JBA makes their headers mainly from 409 steel and they don't cost more than the Doug Thorleys. If these headers were at least made from 409 steel, I'd purchase them in a heart beat, coated or not.