Re: Choice of materials for exhaust manifold.
 

Yeah, like CS said, what you're saying makes sense.

Re: Choice of materials for exhaust manifold.
 

How much do your mild steel elbows cost you?

Schedule 40, 304 Stainless Steel Elbow - 45605K515
$5.89

Re: Choice of materials for exhaust manifold.
 

theres ur first prob, sched 10 stainless els i get em for 4.25 a piece.

mild steel is just flat out not worth it. people arent willing to pay anything for a mild steel mani, evwen though it costs just as much to make.

Re: Choice of materials for exhaust manifold.
 

My time is worth something,and machining stainless steel costs time and machine tools.The other option would be to take the plasma cutter( a real plasma cutter BTW) and blow crap all over inside the manifold.This in turb peels off and gets blasted through your new turbo.

SCH 10 is half as thick as sch 40.If you have a big enough welder you can lay in a much stronger weld.

Re: Choice of materials for exhaust manifold.
 

you dont get slag in the mani if you take a few minutes and make some sheet metal shields for the runneres ect.

tinfoil also works good.

thwe siley plasma cutter burns through sced 10 like butter.

Re: Choice of materials for exhaust manifold.
 

I agreed with everything you said above except for the last statement. Its proven fact that mild steel has a greater percentage of lost material through the course of heat cycles.

Re: Choice of materials for exhaust manifold.
 

I would love to see this tin foil operation.

Re: Choice of materials for exhaust manifold.
 

At the shop I work at, we'll make about 2000 cuts on one bandsaw blade.
They are supposed to last over 3000 cuts, but we punish the saw and use lots of SS for some production projects.

The blade for our Ellis costs about $70.
If we only cut mild steel, that blade would cost about $40.

So for stainless our price per cut is about 3.5 cents and for mild it would be about 2 cents.
I'm going to guess you make 25 cuts per manifold.
That comes to a total savings of 37.5 cents.

Conclusion - By using mild steel you save 37.5 cents per manifold to cut.

Re: Choice of materials for exhaust manifold.
 

ill take pics.

Re: Choice of materials for exhaust manifold.
 

Sorry to bring this back from the dead but i have been doing some research on this topic and found some good info.

http://www.burnsstainless.com/TechAr...s_article.html

Its a really good article and if you know anything about thermal equilibrium diagrams you might get a little more out of it. At the bottom it shows the modulus of expansion for mild and stainless steel and mild is 7.228 while stainless is 9.9 so it doesnt expand that much more. Also if you look at the thermal conductivity you can see that stainless is a much better choice for a manifold since you want to keep the heat in so you can keep your velocity up.