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-   -   CHRA/turbine bolts relaxing. (https://www.miataturbo.net/general-miata-chat-9/chra-turbine-bolts-relaxing-55717/)

curly 02-24-2011 12:39 PM

What about something like a typical MC brace. Just a bolt stuck up against the housing.

miatauser884 02-24-2011 12:40 PM

I was thinking that it might be part of the reason why they would vibrate out of sync. Just brainstorming.

Savington 02-24-2011 12:41 PM


Originally Posted by hustler (Post 693918)

I find it someone ironic that the MSM, which get's so much negativity and considered to be a terrible turbo car" has this problem figured out and I'm looking for a way to replicate it.

I thought your alpha-male driving prowess made the studs in your sister's MSM run screaming like little girls?

TurboTim 02-24-2011 12:53 PM

Now it's my turn to be confused and please correct me whereever I am wrong. You (and Savington?) are currently using stainless bolts, safety wired. The bolts are stretching (not turning out) due to heat expansion and loss of tensile strength at elevated temps, beyond the tensile limit, causing the CHRA to become loose inside the turbine housing and allowing the turbine blades to eat themselves into the turbine housing. This is the problem we are trying to solve, right or no?

If yes, right, then how is vibration the main reason for the stainless bolts stretching, instead of the fact that they are about as strong as a wet noodle at the temps the turbine sees and that even on the smoothest engine the same thing might happen eventually just due to the weight of a turbo hanging off the 6mm bolts? Plus, stainless does grow more than other materials when heated theoretically requiring a higher tightening torque to maintain clamping force as temps rise, assuming you are below the tensile limit for the bolt @ temp (which we aren't due to the vibration forces and perhaps just the weight of the turbo itself). Wouldn't the solution be bolts that are significantly stronger at turbine temps that are either safety wired or held with a tab plate so they don't vibrate loose? :dunno: I'm sure the vibrations don't help at all but other things on your engine that are less hot aren't vibrating apart. (flawed logic?)

In my perhaps completely wrong mind, you can: 1. cool the studs down (tials new watercooled turbine for watercraft), 2. use stronger bolts at high temps (tial supplied inconel bolts), 3. keep the compressor/CHRA from vibrating to the point that the assembly does not load the stainless bolts beyond their yield point & stay stretched (unknown solution...some crazyass voodoo crane). 4. switch to a different setup (T2 flange with trackspeed inconel studs) 5. use larger diameter bolts (possibly room for retapping for 8mm? stainless is still the wrong material regardless of size) 6. Combo of the above. What's easier/cheaper? #3 doesn't seem the easiest to me :dunno:

y8s 02-24-2011 12:56 PM

what turbos use this?

http://www.3sx.com/faq/turboclock/tu...-05big-600.jpg

:inout:

Savington 02-24-2011 01:15 PM


Originally Posted by y8s (Post 693940)
what turbos use this?

Mitsu TD04/TD05s or something.

hustler 02-24-2011 01:32 PM


Originally Posted by Savington (Post 693932)
I thought your alpha-male driving prowess made the studs in your sister's MSM run screaming like little girls?

That would be from the time the bolt in the turbine housing fell out. hehe.

hustler 02-24-2011 01:35 PM

Tim. you are correct and I like #2. Understand that I'm very weary to attempt this without the safety-wire fail-safe.

hustler 02-24-2011 01:36 PM


Originally Posted by curly (Post 693929)
What about something like a typical MC brace. Just a bolt stuck up against the housing.

I assume that when the manifold heats and changes shape, this design won't work.

TurboTim 02-24-2011 02:24 PM


Originally Posted by y8s (Post 693940)

What andrew said, some mitsu stuff. My GReddy kit's turbo was like that. Smart.



Originally Posted by hustler (Post 693956)
Tim. you are correct and I like #2. Understand that I'm very weary to attempt this without the safety-wire fail-safe.

I would not do #2 without a failsafety too, either safety wire or the easier tab plate.

hustler 02-24-2011 02:27 PM

does anyone have a link to those little tabs or any insight on the strongest ones possible?

TurboTim 02-24-2011 02:50 PM


Originally Posted by hustler (Post 693981)
does anyone have a link to those little tabs or any insight on the strongest ones possible?

Sure!
www.mcmaster.com
Item numbers:
1421T61
1661T27
8870A27
4370A6
1257A74
9529K53

EDIT: Oops, safety first!
54185T601
54315T18
5450T13

hustler 02-24-2011 03:13 PM

looololol. I will order the safety glasses though., I keep forgetting to buy them and end up wearing my Kim Jong Il stunna shades.

hustler 02-24-2011 03:39 PM

I just spoke with a local EDM shop who claims they can do this job on Inco, with no problems, for $90. I guess I have a back-up plan now.

JasonC SBB 02-24-2011 03:48 PM

Juuust to be clear, for posterity's sake, and for anyone who stumbles on this thread, and can't read through 9 pages.

For the love of god. Hustler. PLEASE. Post photos of your setup WITH ARROWS pointing to the loosening bolts.

This should have been the FIRST POST.

hustler 02-24-2011 03:54 PM


Originally Posted by y8s (Post 693940)

This is from leMSM.

kaisersoze 02-24-2011 05:15 PM

I didn't think about it but precision turbo has a SS Vband(inlet and outlet) exhaust housing. I emailed them to see what size hardware it uses and if they have had any similar problems reported

hustler 02-24-2011 05:41 PM


Originally Posted by kaisersoze (Post 694056)
I didn't think about it but precision turbo has a SS Vband(inlet and outlet) exhaust housing. I emailed them to see what size hardware it uses and if they have had any similar problems reported

Good try but I expect these are your options:
PT doesn't have anyone driving hard enough to kill hardware
PT doesn't think you will drive hard enough to kill hardware
PT turbo won't tell you if they do
PT won't give you consideration.

I'll test the Inco bolts for you. Then you can get the EDM "drilled" and life successfully through my misfortunes.

bbundy 02-24-2011 06:05 PM


Originally Posted by y8s (Post 693940)

FWIW I had a Mazda 323 GTR turbo on one of my GTX's with a band like that. the band came loose and the turbine hit the housing and destroyed the turbo.

Bob

wayne_curr 02-24-2011 06:10 PM


Originally Posted by bbundy (Post 694064)
FWIW I had a Mazda 323 GTR turbo on one of my GTX's with a band like that. the band came loose and the turbine hit the housing and destroyed the turbo.

Bob

So have you not had this problem with CHRA bolts at all then?


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