mild steel turbo manifold?
 

As i've mentioned before me and my dad are building a turbo manifold. We have already made the head flange out of 1/2 mild steel and have the t3 turbo flange for the manifold. Now I've got to decide on the tubing ordeal.... Im considering a builder kit using mild steel from this site : http://store.racing-solutions.org/bendkits.html
Will mild steel do the job or do i have to worry about it rusting out? Should it it be coated? Chromed (prolly cost alot lol)? What exactly is needed to weld stainless steel, a different type of gas? I've considered using those weld els but my head holes are 1 1/4 and it seems to be a bit harder to find that size if i can find them at all.... Thanks in advance for any help!

Re: mild steel turbo manifold?
 

well to start with what are you welding it with??? If you're tig welding, 100% Argon is tittylicious. If you're mig'in stainless then you'll want:
Argon with, 5-10% co2, 1-3% o2 general purpose, all transfer
90% helium, 7.5% ar, 2.5% co2 for short circuit transfer
Argon with 1-2% o2 for spray transfer
Helium rocks, but it's both outright expencive and you use ALOT of it

If it's just all mild then C25 (75% argon, 25% o2)



Since you're having to ask what gas to use, then yall probably don't weld very well. So skip the CR 16-gauge stuff on the manifold and get some schedule-10 stainless from acestainless. It'll cost somewhat more, but it's not much, and it's afe ---- hairs short of twice as thick. Post-turbo rock the CR stuff to save money. And if the ID of your head ports are 1.25" then get a die grinder and clean them up some. The 1.25's (1.44" ID) at ace are $7.68, while the 1.5's (1.620" ID) are $5.79.

Keep in mind, having a .1-.15 step on the manifold is a good thing. it lowers reversion and its going to get smaller with carbon deposites inside afew months anyway so... Some things are pipe (measured OD) and some things are tube (measured ID) A 16-gauge 1.25" pipe will have an OD of 1.25", ID of 1.12". Where a 16-gauge 1.25" tube will have an OD of 1.38", ID of 1.25".



So don't worry about all the diameter changes you can easily count with pluckings from a furry muff.
btw all manifolds eventually rust out and or crack... Doesn't matter what you amke it out of. It's just that stainless is going to heat your engine bay alittle less and last longer (if made correctly)