I understand this.

But many times in this thread it has been mentioned about them actually spinning out when the nut was held steady. Also, mine did not plastically deform. If >1800deg F for an extended period doesn't do it, then what additionally needs to be added to the equation to make it happen. I don't think its as cut and dry as you are making it out to be.

Didn't Vega mention installing a brace on his turbo and not having issues since. Maybe has has since and just didn't update the status of his studs.

I think a lot of it has to do with not just heat, but the fact that the side mount position puts so much stress on the top 2 bolts. My turbo is pretty well braced by by ewg/dp connection.

I know you had some monstrosity welded onto your old begi setup and it didn't float the boat for you. I think a engine to turbo brace is what is needed to support the entire vertical load. Then again, what do I know, I don't run sub spec miata times......

 

I quess I can let The cat out of the bag here,I have my "welding"degree In Materials Technology.I wrote my senior Paper on Nickel alloys.The only last word answer is...
Inconel studs/bolts with Monel nuts.Inconel has 200,000 psi.tensile strength@1800*
Monel=180,000.Inconel is too abrasive to tap=broken tap or EDM'd threds.I love this thread(and the OtherOne).Its been fun.316/304L Stainless steel will fail past 1200* there tensile strength will is in 2000 lb range and the thermal expansion of the Parts is way greater than that.The Gold star goes to Sav.for the research on Mat.apps.
-G-

 

To me the issue seems to be with cast manifolds. I'm not debating that people are having issues. I just think that a well made brace will work.

Greg - As has been shown by travis's fea modeling, the fasteners do not get to the same temp as the manifold and flange. So saying that the ss studs get to 1200deg I think is not fair. In fact, NO ONE has measured their temp at WOT to make any claim on temperature.

I know that my studs had no issues at all with heat enough to warp a 1/2" mild steel flange. They were still tight along with the nuts. Main differences being my manifold is made from mild steel weld els and my turbo is well braced by my ewg/dp connection.

Is there a consensus that this issue is only with the cast applications?

 

How do you know? If they stretched when the manifold warped, you'd never know (unless you measured them all with micrometers before and after) since they'll work just fine after they stretch once.

Sustained 1.0+ g-forces.

Absorb all the force from the weight of the downpipe and you can hold the turbo on the manifold with whatever you want - including mild steel, which approaches zero yield strength above 1200 degrees.

Really, dude, read the damn thread. ZX-Tex has the same problem with his S4 manifold. GReddy users have the same problem. Not only that, but the worst problems are on the FRONT two fasteners, not the top two.

Stretched the stainless steel bolt holding the two pieces of that monstrosity together. It sure as hell helped, though - I could do full sessions with a leak at the end, whereas before I was at risk of literally losing the turbo after the 5th lap or so.

I think studs that are rated for the temperature and force, vs. mild steel crap, is the ticket.

 

No, this was brought up who knows how many pages ago. I remember it though and don't want to search through the entire thread. Someone was having the issue with Begi S4 tubular manifold.

 

- I know they did not deform because they were still as tight as the day I installed the turbo.

- I can't comment on this.

- Then you agree that a brace is A possible solution? Not to say the better studs is not also a solution.

- No need to be a dick, I have read the thread. I've been keeping up with it the entire time. It has focused, narrowly, on fasteners for the most part. I think due attention has not been paid to a proper brace.

- Again, reaffirming that a brace did in fact help. You particular brace didn't "fix" your problem, but thats not to say that a different one would not have worked better.

- I agree that its a possible solution. I'm just trying not to limit this thread to a single solution. Why not have multiple things that can fix a problem. Put on both and you are bullet proof...



I get that you are trying to help the community fix an issue that you don't even face anymore. That's cool, but don't attack me and accuse me of not reading the thread. I'm not just some noob that just joined this forum. Sure I don't go to the track every weekend like you, but I guarantee that I know just as much as you about these cars. You are too quick to dismiss any solution that you did not come up with yourself.

 

Those studs are NOT getting to 1200 degrees. No way.

I have 1g+ sustained cornering and sub spec miata times. I have had 0 stud issues on my non-vertical mount setup.

I don't know why I bother poking my head in here anymore.

 

Iam not saying they do,I picked a temp that would give a round number that would illustrate a point.Temps dont have to get that high to lose strength,asking a material with a low thermal conductivity to last in a Tensioned state at elevated temp. will cause failure.After which the failed stud will be work hardened and tear up every bit you drill with( not every one,just the ones you guys will be using)Totally hands on experience,no opinions,no modeling,just destuctive weld analysis and repairing the results.
With that being said,I will be using 3/8" 316L shoulder bolts,if they fail nothing to drill out just replace
-G-

 

i'm not going to go back through the thread to see, but is everyone that is having problems using a t2 flanged turbo?

 

Splitime has a t2 flange with 0 issues.

 

Honestly not trying to be a dick,since you've been around a while, but you're re-hashing stuff we've already been over. It's focused on fasteners because it's a fastener problem - a brace would be a band-aid. Yes, they do work, if you put some effort into it - VagaXT is on his 5th or 6th track day on his brace setup.

By that logic, though, we should brace everything. I think if we can find a fastener that will provide the clamping force we need at the temperatures we see, then bracing won't be necessary.



I tried to not attack you, but I guess it came off wrong anyway. I'm working on a solution because I don't like the other solutions people are coming up with, and I want something I can provide to future customers with confidence.

 

.

 

Hi Stephanie, I'd like to order a couple of SS 316 studs from you guys. Do you still have my phone number?

 

Travis,
That's really too bad. Obviously matching CTE's is big, and it'd be a good idea to drill studs and put in thermal logging devices... :-)

Anyway, the question: While it won't do me any good, how about bolts? Can those be had cheaply? They wouldn't even need to be metric. Or, if std thread studs are available cheaply, you might be able to do something there. If I'm already taping my mani for big studs, it's not that bad to tap them american. I hate the concept, but if it's how it is... It's how it is.

 

mcmaster.com has A286 hardware in inch threads.

 

 

I checked our material tracker, and we carry A286.

The last order that went out was for 3/4" x 4" all thread studs...they sold for $14/pc.

I tried to tell Travis he give us a call and see what Sales and Methods could scrounge up...but he didn't take the advice.

We also do the heat treating.

 

Stage8 makes locking bolts, but the problem is that it will be difficult/impossible to fit them into the T25 flange on the turbo unless you went with really short bolts. Then, there might be the issue of insufficient thread engagement in the manifold...

That said, their hardware works as designed.

They are local to me so I will swing by later this week and see if they will allow me to borrow a few bolts to test fit on my car - stay tuned.

 

...and we're back to square one of repost hell. (petaluma > most)

 

I lulz'd a little when I saw his post. You know you did.