While I have not been active on this forum in a while, I have been driving and tracking my turbo NA8.

Unfortunately, after only 3 track days, my ARTech tubular manifold has taken a dump in a major way. Thankfully I am in the habit of giving the engine bay a quick check after each session, otherwise I likely would have ended up with a detached turbo. Here are some pictures of the carnage...







I am an ex-SCCA road racer and current HPDE instructor, so I do go pretty hard on my track cars. However, I definitely expected this to last more than 3 track days!

Rather than attempt to fix this one (I have 0 stainless welding experience) or pay someone to fix this one, I would like to make the switch to a cast manifold. I wish I had done that from the start, but I didn't know then what I do know now.

I emailed a few of the cast manifold companies trying to get turbo placement dimensions to see if any of them would be a replacement that would allow me to reuse my ARTech downpipe and exhaust, but I have gotten 0 responses. So, does anyone know if there is a cast manifold option out there that would work as a direct replacement for an ARTech manifold? Any help is appreciated!

 

I can’t tell from the pictures, are those two flanges parallel? If they are, you might get lucky with a kraken manifold, but if they’re not, you’re probably SOL, unless your turbo downpipe is on a v-band? We didn’t get a ton of info from you. Any pics of it installed?

 

I can't tell if that's a high or low mount.

Those are large hammer marks near the cracks at the 4 into 1.

Are you using IAT related spark retard? Looks like very high EGTs are the possible culprit. Cast will also fail if EGTs are high.

 

I do believe the flanges are parallel. I was already leaning towards Kraken so I may just do that and modify the downpipe if absolutely necessary.

Here are some pictures with the turbo installed from way back when I was trying to sell it... https://www.miataturbo.net/cars-sale...-id1000-96291/

Six, I did notice those marks and never knew what caused them. I will have to dig up the pictures, but I am pretty sure those were there before I ever installed this manifold, and I bought it new from Abe. I certainly never took a hammer to this manifold.

Regarding the IAT retard, I have not done any IAT retard tuning, so whatever is the default should be what I have in place (I am running an MS3X). I have always checked IATs on hot days after on track sessions and never saw anything too crazy. For what it is worth, I also always run with my wastegate wired open at track days in an attempt to avoid things like this.

Edit - Curly, no V-band unfortunately, that is another thing I would do differently now that I know better.

 

I second those cracks caused by unusually high EGT's. It also looks like standard mild weld el's, not stainless. Not that that matters here, and if anything should be better with EGT's. Unless your particular combo's natural frequency is excited where you spend most of your time, in which case adding a triangulating brace vertically from a motor mount bolt may help. Fixing those cracks should not be difficult for anyone with a TIG and argon.

The FM/BEGI cast manifold put the turbo centered with parallel flanges, but looks lower than where your turbo is. This may still be workable for your downpipe.

For reference, my dimensions for the FM/BEGI manifold:

head flange to T2 flange: 3.875"
Centerline head ports to centerline T2 flange: 1.250" up.

 

Pics attached.

 

Tim, this is exactly what I was hoping to learn, thank you!

 

Ok, so after life took over for a while with house projects, I am back to getting this thing running again!

The markings that I can see on the manifold are the following... 1 1/4 WPB STD CX702

Googling that brings up a bunch of carbon steel elbows. But if this thing were carbon steel, wouldn't it be a lot more rusty after 6 years on the car? It doesn't get driven much outside of track days, but I still would have expected more rust.

Also, it is very much ferrous. I am just getting into fabricating (bought a welder not long ago) so I know next to nothing about metals yet, but the magnet pulls hard to get to this manifold. So maybe that reinforces the possibility that it is made of carbon steel and not stainless? I am going to try to repair it on my own for some welding practice. I figure even if I fail, I will just be right back here where I am now. But to repair it I do need to know if it is stainless or carbon steel.

Let me know if you guys have any thoughts!