I would not coat the inside, too much risk of it flaking.

 

Thats what I was worried about too. So what do I do for the inners? Moisture collects there, no? Especially since I am doing topmount so the runners all dip down, and go 180* up? I just wanna tske every precaution I can as I did when I built the motor (thanks for everyones help on that btw)

 

You either dont worry about the rust, or go stainless, which will still rust, just not as bad.

 

Here's 8 years and 40k+ miles.

sorry it's not a better shot, but you can see the #1 runner at the head. The coating is the silvery jet hot style. It's held up pretty well for its age and miles.

 

I'll buy a motor/chasis where people dont have these crazy cracked manifold issues, and run SS 304.

 

Tractor ***** engines

 

y8s, did you coat the inside? Did anyone? Or am I thinking into this rust thing too deep

 

nobody coats the inside for the reason hustler said.

 

The white lightning coating is for the outside only it is not a smooth coating it has a slightly rough texture. Never coat the inside of your manifold, unless you want to risk nasty stuff going thru the turbine. I have a few pics of my swain tech WL coated manifold in my build thread.
https://www.miataturbo.net/build-thr...version-42810/

 

I would suggest using mild steel on the manifold and then coating it with a type of HVOF thermal spray such as SwainTech White Lightening, Jet Hot 2000/2500, or Zircotec. The HVOF process actually embeds ceramic media into the surface of the metal.
The advantage of a properly coated manifold are reduced underhood temperatures and faster turbo spool. The silver "ceramic" coatings that you most commonly see are paints that generally have poor insulting qualities and will not survive on a turbo manifold.

If you insist on having a Stainless Steel manifold I would suggest using 321 stainless or Inconel. 304 stainless is not a good material choice in my opinion.

 

I probably have the first equal length EFR manifold from Artech. I went with mild steel due to the fact that Abe warranties the mild stainless longer than the SS and that you don't need a crane for it. As long as you coat it properly, it should last.

 

I care more about coating for the thermal conductiveness advantage, not "lasting as long."

 

Is Jet Hot a true ceramic? I was under the impression that it was the shiny type.

I can see where you're coming from with the 321 stainless or the inconel, if you're making a thin wall manifold in 16 or 18ga, but even 316Ti would be passable. 304 should still be sufficient even though it lacks the high temp strength advantages that 321 and nickle alloys have over carbon steel. Its very easy to get a clean weld bead (especially 304L) to minimize the likelyhood of a fatigue failure starting in a weld crack, its significantly cheaper, and has been used successfully over and over again in turbo manifolds. I think the crux of getting a 304 manifold to last it making the runners similarly shaped enough that its not trying to tear itself apart when its heated, and figuring out how to support the weight of the turbo while still allowing it to move around as the manifold changes temperature.

 

I actually used your build for a lot of information for my own. Ive seen vids of your car too. AriM on youtube right? How do you like the setup?

 

Yup, that's me. I'm loving it!

 

why in the world would he ever do that.

 

Takes much longer to rust through 1/4" of mild than put a crack in stainless, or warp the hell out of it.

Dann