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Discussion Starter · #1 ·
I´m making me a new exhaust manifold for my 9000 to be able to fit the big GT37 in there. Feel free to take a look at the pics on my site. I will keep puting pics in there this week, will be driving this weekend.

web page

Nóni
 

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Eeeeeep! Those pipes aren't mild steel are they???

Be very careful what materials are used for an exhaust header. Mild steel may work, but it won't last long before cracking.

Generally 304 Stainless can be used on race cars which don't need to last very long, and 321 should be used for any headers requiring long term high heat service.

Heat wrapping will make it worse!

Otherwise though, can't wait to see the results! Might try larger radii bends next time.

Dubbya~
 

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Discussion Starter · #3 ·
This is 316 and 304, I trust that this will be ok.

Some new pics are up, manifold is now ready for welding and installation.

Nóni
 

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Very nice. 304 and 316L may not last on a street car, but they're both very corrision resistant and should survive for short races.

http://www.burnsstainless.com/TechArticles...ss_article.html

"

321 and 347 are known as stabilized grades of stainless. These are alloyed with either titanium (321) or columbium (347), both of which have a much stronger affinity for carbon than does chromium at elevated temperatures. This eliminates carbide precipitation leaving the chromium where it belongs for corrosion protection...remember our discussion of intergranular corrosion? Both 321 and 347 are top choices for exhaust headers, especially turbocharger systems and rotary engines. Since 321 is much more available than 347, that leaves 321 as the first choice, with no sacrifice in needed qualities.

316L is an extra low carbon (ELC) grade of stainless that has only .03% carbon, making less carbon available to precipitate with the chromium. It is used extensively in marine exhausts where salt water corrosion mixed with diesel exhaust particulates and electrolysis create such a horrible environment that even other grades of stainless cower and run away!

304 is the most inexpensive and available stainless in the 300 series. It is suitable for normally-aspirated header applications, and has been successfully used by many racing teams. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. Most 304 tubing these days has the dual designation of 304/304L."

Good information there. Since you don't live in the US they would not be practical as a source for metal, but they have a few really great tech articles.

Btw VERY nice job on matching the exhaust ports with the scroll ports on the turbo. The exhaust pulses should be pretty evenly spaced. That's especially helpful in twin scroll turbo cars.

Looks good!

Dubbya~
 
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