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turbo manifold piping thickness?

Old 08-23-13, 12:03 AM
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turbo manifold piping thickness?

I was curious what thickness of tubing would be recommended for a turbo manifold? Would I be able to use thinner material if I were to use 321 stainless vs 304?

I'm debating on making a manifold for my 13bt 2nd gen. I'm just looking at different flanges people are selling, piping types, thickness, etc.
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Old 08-23-13, 12:33 AM
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Iv just ordered some 16gauge to make my own manifold, 321 stainless. Should be good enough.

Thicker is better as it will be stronger but some bracing will help and stop it cracking. Thicker metal will hold a lot more heat too
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Old 08-23-13, 12:39 AM
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Yeah, I noticed the mandrel bent piping only comes up to 16 gauge. But I also noticed a lot of people are using those cast 304 pipes.

What would you guys think about 16gauge 304?

I also noticed some of the flanges are sold so that the piping fits inside of it. I'm wondering what outter diameter and thickness the flanges were made for.
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Old 08-23-13, 12:58 AM
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If its a roadrace application go 321. 321 is designed for longterm heat exposure without breaking down. If its for a street car either will do. 304 will be cheaper. I would say if its for a street car and a very large heavy turbo go with the thick 304 pipe.

I have 5 roadrace seasons on my 16 ga 321ss 3 rotor manifold and it is still in great shape. The thickness of the material is less important than the specification of the alloy and its heat capacity. I remember seeing some helicopter exhaust parts made from Inconel that were 20 years old and paper thin but still like new.
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Old 08-24-13, 05:16 PM
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Typical Jap manifold in 304 is 12 gauge, you'll still get cracking in the welds - eventually.

All material specs I've seen for 321 have been near as identical to 304 in regards heat capacity, the one advantage is in that weld weakness area, so longevity should be enhanced. I did try to contact Reid Washbon to see if they had anything better than 16g, given your proximity, maybe you can get a response?

I'd add, support the weight of the turbo, rather than just bracing welds...couple of all metal rod ends and a turnbuckle from overhead is the usual solution.
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