# turbo manifold material



## SXSENIS (Jun 9, 2002)

My question is if I was to use mild steel instead of s.s. would that be safe. 16 gauge 304 and 316 are fairly costly and 321 is even more and hard to track down.(I'd be using 304 or 316L because welding it is easier) I was thinking of maybe 409 because polishing is out since I'll most likly send it to get coated at swain. Its cheaper than the others(da 409 ss) and has higher heat resistant properties. It also lasts longer than the other s.steels. But if I'm going to coat it anyway why not use 16 or 14g mild steel. way cheaper and easier to bend and weld. The coating will make it preform better in some ways than plan s.s. It just would weigh slightly more. Mild steel is also softer and one would think it would help avoid cracking(which can be a problem on s.s. turbo manifolds from what I've read).


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## chimmike (Oct 17, 2002)

I think the exhaust gets too hot.

Just remember this man. You gotta pay to play!!!!!!!


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## se-r-57 (May 1, 2002)

Mild steel with the swain coating should work just for this app.


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## SXSENIS (Jun 9, 2002)

The price isn't that big of a deal being a 6ft lenth of the 321 is only 40 bucks or so. I was just wondering why most manifolds are made of s.s. and not mild steel. Is it because s.s. has higher heat properties? Or is it because s.s. has a much higher tinsile strength and that is needed to support the wieght of the turbo?

s.s. turbo manifold should only cost about 200 bucks to weld up compared to a mild steel unit, which would be around 100. Now the labor involed is another story. If you can't weld well you'd be better off buying a complete manifold from a vendor. I'm plannig to spend my weekend to complete it(I figure around two days of tacking and fitment and finishing to completion). I'm making a jig using the exhaust manifold flange and the turbo mounting flange.
Then its just a matter of routing the runner from point a to point b.


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## se-r-57 (May 1, 2002)

Check out www.burnsstainless.com for some good info on stainless. Good luck with the project.


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## Engloid (Jul 7, 2002)

Mild steel will work...think about how many different headers have been made out of it for many years...

If you need somebody to weld it, let me know. I have been welding for a living for many years, and done work for aircraft, aircraft carriers, submarines, space shuttles and more.


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## SXSENIS (Jun 9, 2002)

Burnsstainless did have some good info(which rods to use to combined to diff. metal types) but man they are chargeing like a 30%-75% mark up. You can get 6ft. of 321 for roughly 36.08 from All Metal & Forge. 

And about the mild steel thats what I think too. I'd just need to use a lower gauge like 14. And once its swain coated it'll have near identical high heat resistance as the 321. I'm not looking for something that will out last my car(10-20 yrs.) just last maybe 5 yrs. til it needs to be replaced. I've be welding for almost 2yrs. now, and I love it. Especially when I can use it not just to make money but make myself stuff that I want and save some change for my kid's college fund..


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## javierb14 (Jul 9, 2002)

stainless steel is more corrosion resistant than mild steel. low carbon stainless such as 304L and 321 with ti and 347 are good for high temp applications where carbide precipitation and intergranular corrosion occurs.

stainless also has a lower thermal conductivity than mild...meaning it will insulate more heat thus more energy is available for the turbine.

5 years is long time i've seen cast turbo manis, tubular 321/347/304 manis crack in less time than that. almost all the time, the manis will fail on weld joint itself or near the HAZ. this can be prevented with proper weld preparation, proper filler selection, and most importantly...a good bead

here's an example of the material we use in our manis. its 8 gauge 304L....


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## SXSENIS (Jun 9, 2002)

Well I had no idea when it came to durability. But did know about the corrosion properties. 

I asked for a quote for the 321 and it was about double what thier web site said? I guess since the price of steel varies day to day so it was just a ballpark number.

Is the 8 gauge harder to weld?


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## javierb14 (Jul 9, 2002)

not harder, just a little different. i like to pulse and use a lot of filler.


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## SXSENIS (Jun 9, 2002)

is 16 gauge the same as Schedule 40? The wall thickness I cant remember how to convert it over. I know 16 g is .065 thick or 1/8" thick. And schedule 40 is pretty close. They both have 1.9 O.D. and 1.61" I.d. If so I can do a 304L mani for about 120.

To be honest the most work I've done with weld els and pipe was for some stair case railing we hade to repair and construct(which was the schedule 40 stuff). I've found s.s. 304L weld els Super cheap but they are schedule 40 and I can get 304L tubing 16 gauge for about 7 bucks a foot. Are they not weldable (joinable) because one is cast and one is rolled? Never tried mixing the two before.


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## se-r-57 (May 1, 2002)

16ga is around .065 you'd have to go up to about 10ga (.120) to match the thickness of a weld-l. You can weld weld-l's to tube easy enough. I can any way I've been doin it for almost 30 years


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## SXSENIS (Jun 9, 2002)

You sound like my boss. 
I can do it but it'll take you some practice. Hey man will you help me? NO! But you can use the shop if you want....Haha.. Why you wanna blow up that damn car ? I love it and want to spank your vettes ass. Oh no get outta here. You need a american car. Will see will see.

Sorry he rains on me for the heck of it, but its cool. its how we get along. So you say it shouldn't be that hard? Great I Ordered some practice elbows and we got plenty of scrap around the shop so I guess I'll start soon as I can get the welds lookin good.
( he calls my welds bubble gum!)

The schedule 40 stuff is like 0.145. So javierb14's 8 gauge is right on. Steps are bad for flow. Thanks for all the info and input. Its been priceless.


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