Had another track day after the Shelby day in August. SO close to getting into the 1:30s, best was a 1:31.079. Was my first time with bringing my own fuel to the track, so I was able to keep myself topped off throughout the day. Not too much to report other than that.

Now it is winter time, and my only project for the winter is swapping in the Poly/Bronze bushings. Acquired an extra set of control arms, cleaned them up, and painted them today. Needless to say, I won't be getting into automotive painting anytime soon because the paint job sucks. However, it is functional.
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Maybe I'll try to clean it up a bit, but honestly I don't really care. Metal has paint on it for rust protection, not going to be a show car.

I also have the whole "turbine wheel is missing bits" thing. I was going to get a new supercore, but for budgetary/spousal harmony reasons I'm going to put that off. Maybe it will fail catastrophically this next summer and get replaced, but until then I'm probably going to keep running it.

Was it 30 degrees outside in Salem like it was here in OC? Might explain your drips.

Yeah, it was pretty cold. I knew the weather was less than ideal, but I figured this is probably the last dry weekend we'll have for several months.

Once again, it seems like my turbo hardware is coming loose. The locking hardware seems to be doing it's job for now, but this is the second time this has happened. Both times installed by a competent shop, with Resbond and everything. I'm about at wits end, my understanding was that this wasn't supposed to be a problem with the Trackspeed kit? Any ideas?

How is it coming loose? Did you use resbond on the inconel studs when you installed them into the manifold?

Last summer I had a whole stud back itself out and fall off on the front straight of Portland International Raceway, with a couple other also on their way. This time it's just one for now, the lower right if you are looking at the exhaust side of the engine. Can't quite tell if it is the whole stud/nut assembly backing out again or just the nut, need to get some light, mirrors, and another set of hands.

Resbond was used on the manifold to stud interface, stud to nut, and then the whole thing was covered in even more Resbond. @curly at AR Motorsports did both the initial install and the re-do after losing the first stud.

And you have stage8 nuts and lock washers on it?

How much faster then spec miata times do you run? Are you picking up 6 or 7 women each weekend at the track? As you seem to be going fast as fuck if you are starting to break all this stuff.

Maybe what we figured out with v-bands a decade ago was correct. I think my absurdflow setup just went up in value.

Yep, Stage 8 all the things.

That's the thing, I'm NOT that fast. I'm just under the Spec Miata record for my personal best with 225 RS-4s. Hence, the confusion with the hardware issues. Times are on wastegate pressure, so roughly 220whp.

Well then I don't have a good answer for you. I would say to contact Savington, but I don't think that is really feasible any more.

Yeah that's a bit of a shame eh?

Do you know what version of resbond was used? If my mental picture is correct, the stud that came lose is the one exposed to the highest temperatures? (also the trackspeed kit was M10 or M8?)

Maybe could be an idea to look into an adhesive with a better CTE match to Inconel 718 (which I believe is what they used in the kit). Same makers as resbond, but maybe this Durabond 954 stuff would do the trick -- http://www.cotronics.com/WEB%20SHEET...2%20%20954.pdf

They're M8, we used Resbond 907TS Red. It was dripping off the studs when installed into the manifold and nuts onto them. Only way I could have gotten more would have been to assemble while submerged in a bath of Resbond. Stage 8 hardware was trimmed to be as close to the turbine housing as possible, I probably still have the burn scars on my finger tips to prove it.

While I work at a reputable shop and seem to have a decent reputation around here, I'm open to ideas about what I could have done differently.

Just to be clear, I'm not blaming you. I'm just surprised that the issue it coming up again so soon. I can't quite remember for sure off the top of my head, but I've only had two or three track days since it was in to get the studs replaced. I'm assuming that because I don't see a bunch of other complaints re: the Trackspeed setup that the issue is unique to my hardware. Just wish I could figure out what it could be so it could be fixed. Unless re-Resbonding studs every 3 hours of track time was a normal expectation that I was unaware of.

I wonder if you could set screw the studs into the manifold, using a smaller thread pitch with no real load against it might actually stay in the manifold better than the studs and resbond.

The nut shouldn't be able to turn due to the locking hardware, but the stud still can even with resbond apparently. Maybe a set screw would be all it took? Then the stud just has to not stretch, because it might not come out cleanly again...

Yeah, mea culpa if that came off accusatory in any way, the only standard method to install these I've ever heard of/seen is what you describe (probably in part due to how much I've used these forums as an encyclopedia).

Was just spit ballin on what could be a more optimal solution moving forward. Looking at the datasheets, the 907TS is mica platelets in ceramic binder, hence the relatively low CTE -- 4.5*10^-6/degF. The Resbond 954 (and I think specifically the OD model is also a sealant/low viscosity/not putty), but uses stainless steel in a ceramic matrix and has a CTE of 10*10^-6/degF. This is much closer to Inconel 718's CTE of 8-9 and stainless steel's of ~16-20 (at operating temperature). From their marketing blurb: "These metallic composite adhesives overcome the brittle bonds obtained with ceramics and offer some of the ductility and impact resistance associated with soldering and welding." The ductility of the matrix should also help with repeated cycling vs. the mica based 907.

The "cold" bond strength of both is within shooting distance (450 PSI for the red 907TS and 600 for the 954), but you'd probably still want to test that you could, you know, still take it apart after the fact.

The other thing to look at would probably be the torque on the bolts when cold? Perhaps less is more in this instance.

Anyway just my 2 cents of ideas for what to try next, I certainly have no way of knowing if they'd be good ideas however.

I was able to take a closer look just now, and it looks like it is just the nut that is loose. The stud appears to be fixed in the manifold pretty well, so that's good news. I can tighten a nut. Now I guess I need to track down a little bit of Resbond.

You're welcome to come borrow my bottle. If the stud is tight, I would also look into some sort of stage 8 failure. IIRC, that stud is particularly difficult to make the tab decent at locking.

Thanks for the offer! I might take you up on that.

The tab on that nut does seem particularly loose. I'll see if I can get it off this morning and see if it needs to be replaced.

Good gracious, it is REALLY tight around that stud assembly. Don't see how I can get that nut off for more Resbond without loosening everything else up and taking the turbo off. Been fiddling with the locking tab and might be able to get it off, but I worry about putting it back on now.

So current thoughts are:
-See if I can get that tab off
-Get Resbond, loosen nut to extent possible and put Resbond on stud.
-Tighten nut, put Resbond over the tightened nut
-Re-install locking hardware, try to put locking tab one knotch closer to the turbine housing to lock in place better
-Hope I don't have to deal with this again anytime soon

Worth a shot?

I think that one might have to thread on with the turbo off the manifold. I might be wrong.

as a side note, I’m replacing the turbo nuts on Mclaren’s version of the MX-5 Cup car, the 570s GT4. They weld both the studs to the manifold, and the turbine housing is tacked to the manifold.


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Sitrep: tightened the nut, and when putting the locking hardware back on I dropped the tab and it must have gone through whatever interdimensional portal 10mm sockets fall into.

Still, nut is tight and has Resbond so I've done a little street driving and even an autocross on Sunday. Ran into Toyabie which was fun. Car will be going up to AR again in a month to get the locking tab trimmed and installed. I'll also be looking into contingency plans if stuff comes loose again. May end up completing the MT.net circle of life despite buying all the hardware that was supposed to make that unnecessary. :(