Thermodynamics of stainless headers

[NHRA 303]

Okay Ive combed the net. And i cant seem to find any information explaining how stainless steel headers perform over standard mild steel tubing. Ive seen the results for myself. And its very impressive. I know it has to do with the improvements in thermodynamic flow of the header tubing itself. But due to what exactly?
Thank you in advance my fellow racers.

Steve Tucholsky

[SSDiv6]

Originally Posted by NHRA 303

Okay Ive combed the net. And i cant seem to find any information explaining how stainless steel headers perform over standard mild steel tubing. Ive seen the results for myself. And its very impressive. I know it has to do with the improvements in thermodynamic flow of the header tubing itself. But due to what exactly?
Thank you in advance my fellow racers.

Steve Tucholsky

http://www.burnsstainless.com/stainlesssteel.aspx

http://www.perfweldheaders.com/svsm.html

[Alan Roehrich]

I suppose I'm biased, but I don't think stainless out performs mild steel if the mild steel has the correct coating. And the coating works real well on stainless, too.

[Jim Kaekel]

Once you go stainless, you won't go back. It doesn't matter if you get mild steel headers coated, they will still rust after a while on the inside and outside. Then, every time you spin your motor over, you're pulling all that rust into the engine.

[jmcarter]

Use SSDiv6's link to get Mark Lelchook's contact info and give him a call. While the main reason for stainless is longevity Mark can give you more insight into the properties of stainless and it's advantages. Plus his work is absolutely craftmanship at its finest.

[Greg Reimer 7376]

Stainless steel doesn't absorb heat along its surfaces. It reflects it.Chrome moly or mild steel absorbs heat as the exhaust travels along its length.Seems to me that the exhaust temperature leaving the collector would have to be hotter than the other material headers. All of your wives probably have Revere Ware stainless cookware. The reason the base of the pots and pans have a copper coating bonded to it is so that heat absorption will occur, otherwise food wouldn't cook very well. The heat from the flame would just go around the pot on its way up. 80 or so years ago, railroad mechanical engineers, always looking for more efficiency,tried building a steam locomotive boiler with stainless flues,in an attempt to cut down on rust, frequent maintenance, and constant boiler flue replacement. That engine steamed so poorly that it couldn't get out of its own way, so seamless steel tubing went right back in. I also would surmise that under hood temperatures on cars with stainless headers would be lower due to the same factor.

[NHRA 303]

WOW. Thank you so much for the great reply's. That makes so much sense. Even in my original question "Thermodynamics". I guess i was looking for a fluid dynamic answer, to a thermodynamic question.
After reading the "Burns article". It just made sense. This pretty much says it all:
Typical 1010 carbon (mild) steel conducts 219% more heat per foot than do the types of stainless steel we use in header fabrication. By contrast, quite a bit more heat stays inside the stainless header tubes and does not get passed into the surrounding air. By not allowing the contraction of the cooling gases as they flow down the tubes, more exhaust velocity is retained which promotes better scavenging at the collector. This retention of velocity increases the overall header efficiency.
Thanks again everyone. I luv reading all of your posts to every subject.

Steve Tucholsky

[SSDiv6]

Originally Posted by NHRA 303

WOW. Thank you so much for the great reply's. That makes so much sense. Even in my original question "Thermodynamics". I guess i was looking for a fluid dynamic answer, to a thermodynamic question.
After reading the "Burns article". It just made sense. This pretty much says it all:
Typical 1010 carbon (mild) steel conducts 219% more heat per foot than do the types of stainless steel we use in header fabrication. By contrast, quite a bit more heat stays inside the stainless header tubes and does not get passed into the surrounding air. By not allowing the contraction of the cooling gases as they flow down the tubes, more exhaust velocity is retained which promotes better scavenging at the collector. This retention of velocity increases the overall header efficiency.
Thanks again everyone. I luv reading all of your posts to every subject.

Steve Tucholsky

Steve,

You were actually looking for a Gas Dynamics response which happens to be related to Fluid Dynamics.

Here is a link to a good treatise regarding Gas Dynamics.

http://www3.nd.edu/~powers/ame.30332/notes.pdf

[James L Miller]

Originally Posted by SSDiv6

Steve,

You were actually looking for a Gas Dynamics response which happens to be related to Fluid Dynamics.

Here is a link to a good treatise regarding Gas Dynamics.

http://www3.nd.edu/~powers/ame.30332/notes.pdf

Boy I was right with you until I hit the bit on tensors. It's been 30 years since I did that in college and I've sort of forgotten most of the mathematics.

[Andrew Hill]

Originally Posted by SSDiv6

Steve,

You were actually looking for a Gas Dynamics response which happens to be related to Fluid Dynamics.

Here is a link to a good treatise regarding Gas Dynamics.

http://www3.nd.edu/~powers/ame.30332/notes.pdf

I've seen notes very similar to those before!