Turbo exhaust manifold - materials

[BobDcuda]

I'm working on turbocharging my slant six motor for eventual switch to Modified class, and could use some guidance about which materials to use for the exhaust manifold.

I understand the place for 321 stainless for such a high heat application, but I was a bit surprised by the cost of a piece of .500" thick 321 plate for the flanges.  Some of the available tubing and bends seem a little more reasonable.  Could regular 1/2" steel work OK for the flanges, and then the rest be done in 312 stainless?

I'm planning to make a log-type manifold with short runs from the exhaust ports.  Would 16ga bends be adequate of the manifold and turbo are adequately braced?

Any suggestions or guidelines you might offer to make sure I do this right?  Thanks....

[Dynoroom]

Yes you can use steel for the flanges. You don't have to use 321. I've used forged schedule 40 steel tube in the past with much success. For the limited run time at Bonneville it holds up very well.
You can also live with 3/8" flanges if you want.

[BobDcuda]

Thanks Dyno - helpful information.

[kiwi belly tank]

The stock exhaust manifold will get the job done for you, it just won't have the eye appeal but you're running a 170 aren't you?
  Sid.

[BobDcuda]

Sid, yes I'm running the 170.  The turbo I chose is the Precision 6266 which should  give me more HP than I can handle.  Should be more HP on tap than I can use, so no need to get too exotic.  Thanks for your input!

[kiwi belly tank]

If you use the stock one grind the heat riser box off it to get it away from the intake. Which ever way you go, put a blanket on it & the turbine housing to stop the heat transfering to the intake.
My friend makes custom three layer blankets that are so good you can put your hand on them & it feels like warm laundry plus it won't cost you an arm & a leg.
I can PM you is info plus you can google his reputation.
  Sid.

[BobDcuda]

Sid, please do PM that info.  I've seen different versions of  the cast manifold modified for turbos, but I wasn't sure how well that would work for a 3 mile cruise at WOT.  Thanks again!

[kiwi belly tank]

Waaaay back in Aus I ran a turbo'd 225 in a small hydroplane with a stock exhaust manifold & blowing through a Holley on a modified stock iron intake. I had the exhaust manifold wound up with aspestos rope , it's a wonder I'm still alive!
PM sent.
  Sid.

[BobDcuda]

PM received - thanks!

[NathanStewart]

I've used stainless sch 10 weld els from Ace Stainless Supply to make my turbo manifolds.  That's a Precision 5557 with v-band in/out hot side on my Ecotec.

[Buickguy3]

  These are the $99 special block huggers for a small block Chevy.   

    Doug 

[Stan Back]

I guess you found the secret -- Arkus Duntov used to own a Roadmaster.

[kiwi belly tank]

  These are the $99 special block huggers for a small block Chevy.   

    Doug 

Good one Doug, eight hole's is eight hole's!
  Sid.

[Elmo Rodge]

And six holes is six holes. I used a Mustang V-6  header for the basis of my Flathead headers.  Wayno

[Tman]

As Dynoroom posted, the Weld Els work great. Any plumbing supply will have them. On my lakester thread you can see them in use. If you want stainless look at Fastenal. I got header flange material there for a fair price.