Stainless manifold Grades

[Mark One]

Techy question here,

Stainless steel grades for turbo manifolds. What's good, what's not good.

I've heard 321 and 347 are good. 328 is not good.
anyone have any idea - is this true - why?

 

[sideways danny]

most cheap stuff will be 304, which cracks pretty quickly normally. 321 is meant to be better at dealing with the heat, but the temperatures i've seen quoted as it being stable are still a couple of hundred degrees below EGTs I've known on turbo setups. The trouble with stainless is it's rate of contraction on cooling. I chose mild steel steam-pipe for my manifold, it's held up for 35k miles now which is far better than any stainless one I've had experience of

 

[Fred@BTM]

316 grade sch10 is about the best off the top of my head

 

[sideways danny]

316 grade sch10 is about the best off the top of my head

believe that's the stainless equivalent of the mild steel matierial used to make mine

 

[Mark One]

cheers dan, that's interesting. I had heard about mild-steel manifolds but tbh I'd originally dismissed it as a bit of a cheap compromise. I was clearly wrong

 

[sideways danny]

cheers dan, that's interesting. I had heard about mild-steel manifolds but tbh I'd originally dismissed it as a bit of a cheap compromise. I was clearly wrong

there can be issues, but if you're aware you can combat them. Scaling is something to watch, and about the only thing i'm worried about, but you can ceramic coat internally for not too unreasonable money

 

[Icarus]

316 grade sch10 is about the best off the top of my head

Seconded - if you must have stainless then I can't think of a better option.

There is nothing wrong with mild for a manifold though and chances are it will be more durable than a manifold produced from stainless.

Cheers
M

 

[Mark One]

thanks for that guys.