gtred

After reading up on the "track reliability" thread, I ordered better flange studs.

I've just received a set of inconel studs from FM... they are the wrong size for my application. It turns out that BEIG is using oversized studs (M10) on their manifold-turbo flanges.

Are the bigger studs a "fix" for the problem of OEM bolts streching under heat? Or, do I still need to purchase inconel in this larger size?

I would hate to spend $ on over engineering a problem that the larger studs would have fixed.

fooger03

iTrader: (2)

Having more apple pie does not change the fact that the pie will still be eaten eventually. A turd pie solves the problem altogether.

The non-conel studs fail because they reach plasticity within the range of operating temps and expand at a different rate than the cast turbine housing/manifold.

The in-conel studs expand at a rate much more comparable to the cast parts, and their plasticity occurs at a higher temperature threshold.

The non-conel studs would still have issues, even if they were 14mm.

crashnscar

iTrader: (9)

Completely depends how hard you drive the car. In short, yes, there are still issues and simply going to 10mm studs does not fix the problem.

Trackspeed Engineering Inconel Stud Kit is 10mm and will solve the problem: http://trackspeedengineering.com/sto...-kit-p-98.html

gtred

will do. and, thx for sharing your experience.

mx5-kiwi

This is a bit vague of a question but I don't know a better way to phrase it.

At what power level does the stud problem start happening, I have had to have the manifold planed once already only running 6 psi. The engine guy said it must not have been flat to start with but now I wonder if the studs stretched or something causing the warping....

Car is at 6psi and going to 8 ish is planned in the future, currently do track days, not racing and some DD......are the inconel studs something I should look at too...?

DeerHunter

I've had broken stock studs on a 200 whp Greddy kit and on my 350+ whp FMII. I now have Inconel studs and the downpipe brace and hope that's the end of it. Mainly street driven with about an autocross a month and the very occasional track day.

Faeflora

iTrader: (2)

Nah i just use wooden dowels.

fooger03

iTrader: (2)

General consensus seems to be that the studs start stretching on track cars running spec miata times or faster. YMMV, but some factors seem to exaggerate the problem, such as if your studs actually contact exhaust gasses. If you seriously think you're going to have this problem, then read through the 55 pages of epic studs thread.

hustler

iTrader: (6)

Why chance it?

bbundy

If the problem occurs for you just going to 10mm studs won’t fix anything. Inconel seems to do the trick more times than not.

It really sucks to go to the track and have your turbo falling off before lunch.

Bob

mx5-kiwi

At the chance of getting ripped a new one.....

Are these failures just at the turbo to manifold joint?

I have now read about 40 of the 59 pages and got swamped with so many things i lose track. I have recently had to have my exhaust manifold re planed due to an exhaust leak and warping, the engineer guy said it wasn't flat to start with but I find that hard to believe. It happened after a track day and the turbo setup seems reasonably well built..I bought the car from my fathers boss who had it built by an experienced (I believe) turbo company down here.

So my concern is that I may be seeing similar issues...but so far the turbo to manifold joint is okay (touch wood). At $300.00 odd a go, that will get old fast....

TorqueZombie

iTrader: (6)

I have trackspeeds 10mm studs, the car has been driven to class and back once. They never stretched. Even siting in the garage. They're amazing. FYI, overbuild. Not under build. The stud size isn't what makes them good. It's the material. It's why barb wire doesn't make for a very good sex toy, kittens don't do so well at becoming roll bars, and Italian wine doesn't make a good fuel source. and yes...been drinking

fooger03

iTrader: (2)

As you continue reading, you'll start to see where some of the guys have picked up inconel CHRA to turbine bolts and fastened them to one another with safety wire. The block to manifold studs seem to use the block as an effective heat sink, and the turbine to downpipe studs just haven't seemed to cause problems for some reason.

crashnscar

iTrader: (9)

Yes, just at the manifold to turbo. If you are having issues with the manifold to head, your manifold was most likely not flat to start with. Now that you have had it surfaced flat, I don't expect you will have any issues with that joint. Run an OEM exhaust manifold gasket between the head and manifold, nothing between the manifold and turbo (just make sure both surfaces are flat with a machinists straight edge).

mx5-kiwi

Good news, thanks crashncar.