I have the same problem. I had a local shop drill the bolts last week and spent nearly $100 doing so. I am still running on a damaged turbine wheel because I want to confirm that these bolts work before spending $450 on another CHRA (this will be my third).

IMO one of the big reasons is the M6 hardware TiAL uses, vs. the standard M8 hardware that Garrett uses. I haven't heard of this issue from Garrett-housing users with our Inconel studs installed.

 

Is there no room to drill oversized and tap? That ***** easy since there's already a hole to center on.

 

Do you think the Tial housing could be machined for larger bolts?

 

Don't know. The Inconel hardware appears to be holding up so I'm not going to mess with it anymore.

 

I wonder if you can laser cut the wire holes

 

These are the old stainless bolts? I see writing on the head. Their inconel stuff has no writing as they are made from rod stock.

I haven't read to the 6 pages yet but I'd consider drilling out the 8mm stuff and running 10mm inconel hardware. Perhaps cutdown trackspeed stuff?

And the cranes I see so far seem to be designed to help with cracking of the manifold, not the removal of the CHRA from the turbine. But I guess stiffening the entire assembly will change the harmonics of the CHRA somewhat regardless. You can try a EFR turbo. I'll weld on a T2 or whatnot flange for ya for teh cost of the flange + shipping.

 

That's the standard stuff, Inconel is off to a machine shop.

I appreciate that, but I'm not sure what I'm doing yet, most likely the most cost-effective option which is to deal with what I have. The issue right now is totally managable of course, just not picture perfect.

 

Because you've safety wired stainless bolts, not inconel bolts? I have one set of older-gen drilled tial inconel CHRA bolts here...kept them when I noticed tial stopped predrilling them and if I ever build a track car I might need them. But I know I won't ever build a track car...

I'll take one of my current-gen tial inconel bolts to work and see if they can drill them.

 

Are they the short bolts that look like the ones in my picture, or do the have the larger "head"? If I can't get mine drilled by JohnWag's friend then I'd love to get you to help me out. You've helped me out so much with this car too, lol. If this stuff doesn't cost me too much I'm going to get my car balanced and aligned if I have any money left.

 

The predrilled tial bolts I have are the older ones with the 8mm hex above a larger washer surface. The newest tial bolts are back to a 10mm hex like the original stainless hardware. BTW, the tial hardware quality sucks in general.

What diameter safety wire are you using?

EDIT: Didn't you buy a drill fixture?

 

what about bent tab retainers that bend over the flats of the bolt and around the side of the retainer plates?

or just a second thin retaining plate that has tabs to bend up over the sides of the bolts. It would be disposable but so what.

 

I actually just turned my computer back on to mention this. Kaisersoze mentioned it earlier in this thread too (how's your setup holding up kaiser?!) I drew a tab plate out actually for Hustler's build back in the day but he went with drilled bolts, hence me remembering him mentioning a drill fixture at one point, bought off ebay. It'd be relatively easy for someone to make using a dremel and those simple cutoff wheels. Get some 1" wide, thinass stainless strip from mcmaster, trace the tial tab/clamp thing, make it a little longer on each end, cut it and make 2 others the same length, clamp them together, cut em out.

Or spend a bunch drilling for safety wire and time to thread it properly?

 

I bought a safety-wire jig but can't seem to find a drill bit that cuts or doesn't slip in the chuck.

I use .032" inconel wire with a meticulous effort in safety-wiring to put lots of tension on the wires, usually 2-3 attempts per wiring.

Do you think the new TiAL bolts are also bad? Why is it so hard to get a quality Inconel bolt to fit our needs?

 

The new bolt is the same alloy as the old bolts. Some sort of nickel alloy. They are "better" than stainless. I have the SEM/EDS percentages at work and the rockwell hardness....i remember it not being very hard. I'll post tomorrow the #'s. I do not know why it's hard for tial to produce a quality fastener. There's plenty of jobshops that can make a quality inconel bolt for tial (in quantity that's not realistic for us people). Unless they are making them in house and have a real shitty machinist and/or tooling. It's the quality of one bolt to the next that sucks ***, not necessarily the alloy. One bolt will have a completely different major diameter on the thread than the other bolts, another will have a wider hex requiring filing your harbor freight wrench to slip over it, some aren't deburred, chamfer sizes vary on each bolt, overall lengths vary, etc.

Odd, the machine work on their other parts tends to be very very nice.

 

I'm not sure why you guys switched to inconel and the reasons why it 'works' better but ti bet its thermal expansion rates. from matweb:
http://www.matweb.com/search/DataShe...e6369bc&ckck=1
http://www.matweb.com/search/DataShe...3eaa74fe812895

inconel 600 CTE (coefficient of thermal expansion... ie rate of expansion per unit increase of temp) is 13.3 vs stainless 301 being 16.6.**

So, Hustler I feel your doubt... i certainly wouldn't want to screw up another turbine wheel on a 'might' work (the material property in question is within ~50% of each other) ...I'd want safety wire as well. I'll add that proper torque will be important. You dont want to over stretch the bolts and make them weak, but under tightening them will allow vibration and that is way worse. the change in preload with the extreme temp changes makes the problem more challenging....all the more reason for safety wire.

*** that is for generic *** stainless and inconel, materials that are fastener specific will likely have a lower CTE. Also, drunk engineers tend to ramble...YMMV.

-Brad

 

My setup? Sigh, afraid I don't have much to add on this subject. In the short time it was running it was never pushed in the way hustler or Savington's setups are. Now we are trying to get the first miata to run on Hydra 2.7. Plus the low oil pressure issue. Like with any project you reach a point where you despair whether or not it will ever run. I'm there.
I sent Tial an email asking whether it would be possible to tap the housing for larger bolts just for better clamping force and less chance of stretch but they have yet to get back to me. If not I will probably do drilled bolts and safety wire as well.

 

Yeah typical nickel alloys have a lower CTE than stainless steels, closer to mild steel like the typical CHRA. But they have much higher yield strengths especially at temperature. At 200F inconel 718 has a yield strength of 204000psi, 304stainless is 31200psi. Yeah. The % difference gets greater as temps rise.

 

Tial replied that they don't think there is enough room to tap the housing for larger bolts.

 

About that phi-rho-Z EDS percentages for the Tial bolts. Percent by weight:

Cr: 19.86%
Mo: 2.60%
Fe: 18.10%
Al: 1.59%
C: 2.47%
Ti: 1.09%
Balance Ni: 52.38%

Hardness: 29-30 Rc

I have some pointers by one of the machinists here about drilling holes into this material, I may try it someday this week at home after I buy some drill bits.

 

Bravo, sir.