Header questions

[turbo89]

I don't see how that would help my header from cracking the way it does except for the weld around the base of the turbo flange.
But the cracking around the weld at the collector is another issue.

the crack in that pic I see is from weld technique and HAZ of the weld as well as the major cause that the FLANGE is holding all the weight of the turbo ... take the weight off the flange supporting the turbo.. Cracking weld at the flange is what is causing the other issue ... to do that right you would have to cut off that entire section and redesign that header for your application.
you will keep patching that and NEVER fix it otherwise.

A custom header would solve the issues.. but that header would be designed for your application ( which isn't really what the header your using is designed to do). If this is a sand rail you would have plenty of room for header design and customize it to prevent the issues.

 

[gnpoweredrail]

I agree but it would still need to bolt into place(preferably) so I wouldn't have to redo all the other piping.

 

[Nick Micale]

You have a heavy-ass turbo shaking and vibrating like crazy over the sand and you expect a thin-wall tubing to stand up to this abuse?

Not to be an ass, but we have had this problem and I illustrated one way to support the turbo with a reinforced steel bracket, not dependent on the main structural item to be a tube with very little life when subjected to fatigue forces like you expose it to especially off-road?

Maybe a header with .125" wall would survive, but a custom, reinforced turbo support bracket attached to the head or frame will most likely solve your issue, as a thin-wall stainless tube flexing at 1600 degrees is NOT going be a reliable fix.

On one race car we made a bracket on the frame to mount the turbo, and built the header to it since there was no way any header was going to support such a heavy turbo.

 

[gnpoweredrail]

that's my plan like I said in one of my previous posts. I am going to fab onto the factory j bracket to bolt to the other hole in the head and probably the compressor housing. Also thinking up some kind of mount from the frame as support as well.
I was just asking who makes the thickest headers or who can make me them. What grade stainless would hold up the best.

 

[turbo89]

that's my plan like I said in one of my previous posts. I am going to fab onto the factory j bracket to bolt to the other hole in the head and probably the compressor housing. Also thinking up some kind of mount from the frame as support as well.
I was just asking who makes the thickest headers or who can make me them. What grade stainless would hold up the best.

.083 321 stainless is as strong as your going to get and not get STUPID expensive .. but if you don't use proper welding and support the turbo directly .. with the forces you are applying it will eventually fatigue ...

personally I would use a .065 321 stainless header ( correctly designed) won't have any issues in your application... there are far harsher environments than what you have that are not having issues using 321 stainless in .065 wall..

You can use .250 wall and if not correctly welded and using cheap chinese flanges it will crack ... (what your seeing )

in short... CORRECT DESIGN .. PROPER WELD TECHNIQUE .. CORRECT MATERIAL SELECTION = CRACK FREE HEADER

The downpipe and X over should be the last of your concern to fab up.. those are a cake walk

If you need help with this particular project PM me ..