Cast iron for engine tubo exhaust manifold??

I want to get a cast iron turbo exhaust manifold copied. The stock ones, made by HKS in Japan, have a tendency to crack when used on track. I don't believe the design to be at fault, more likely a material problem. I have been told a high nickel content cast iron is better, can anyone recommend a good material spec or otherwise advise on what i may need? Is there an alternative to cast iron for casting such items? I will only be wanting about 6 made, no big production run! Cheers. Photo of what I want to copy is at

The tooling costs will kill you at 6 off prices. The coreboxes would give a pattern maker nightmares.

Steve

For 6 off you might price out tig welded stainless tubing. For a little extra HP lag [insulate] the manifold.

Unka George (George McDuffee)

There is something to be said for government by a great aristocracy which has furnished leaders to the nation in peace and war for generations; even a democrat like myself must admit this. But there is absolutely nothing to be said for government by a plutocracy, for government by men very powerful in certain lines and gifted with the "money touch," but with ideals which in their essence are merely those of so many glorified pawnbrokers.

Theodore Roosevelt (1858-1919), U.S. Republican (later Progressive) politician, president. Letter, 15 Nov. 1913.

that's a nasty piece of work. i second george's thoughts on getting a custom tigged stainless manifold made - one with equal length tubes to each cylinder. it'll flow a good deal better than that ugly thing...

Try posting in sci.eng.joining.welding couple of guys in there specialise in making manifolds.

Steve

Brilliant stuff whats it called?