[Mk2] [Turbo] Help with CT26 Turbine Identification - Ceramic/Metallic

[Danbob]

I think I've figured this out for myself, but I'd like a second opinion.
Identifying CT26 turbine wheels - Ceramic wheels Vs Metallic/Alloy wheels.

Here's the only half decent info I could find online.

Inconel/Metallic wheel on the left, Ceramic Wheel on the right

So according to this info you can identify the wheel type by the shape of the nut, 6 sided for Ceramic, 12 point for inconel/metallic alloy

Info is from here:
http://www.mr2oc.com/showthread.php?t=282510&pp=30

This info ties up nicely with the three turbo's I have at home.

Turbo number one is a totally standard CT26 from JDM Rev2 MR2 Turbo so should have ceramic wheel:

You can see it has the six sided nut - 11 fins


Second up a Turbo Technics rebuilt CT26, when I gave them the serial number they told me the turbine wheel had been replaced with a metallic turbine wheel.

12 point nut, - and only 10 fins

Finally my Hybrid CT26, which is the one I actually care about:

This one also has the 12 point nut, and only 10 fins.


So can anybody confirm definitively how to identify the "steel" wheel (alloy) turbine compared to the ceramic. Is the nut shape test accurate.

Can anyone confirm if ceramic turbine usually has 11 fins and metallic has 10 fins?

From what I've found, neither will be magnetic so can't use that to test.


I did try using the search feature to find this, but it always just brings up loads of irrelevant stuff

Cheers
Dan

[Peter Gidden]

Magnetic?

[fingers99]

From what I've found, neither will be magnetic so can't use that to test.

Inconels -- if that's what the metal ones really are -- can be magnetic. Nickel is its main component (magnetic) together with 10% or less Iron (magnetic) and other things.

Still, the other alloys reduce or eliminate its magnetic properties, so it probably isn't a reliable way of testing -- its magnetism is also temperature dependent (and responsible, as such, for at least one aborted Space Shuttle mission).

I'd suspect that they actually feel very different, but have never had either, knowingly, in my hands.

Only thing to add is that if it is magnetic, it's surely not ceramic.

[Danbob]

Thanks for the extra info, I think inconel or other similar nickel based alloys (inconel is a brand name) are pretty commonly used for turbine wheels, its inconel exhaust manifolds and turbine housings that are the stuff of extravagant WRC budgets. I can't confirm either way what the ct26 "steel" turbos are though, just a theory.

Yeah I tried the magnet test first, and none of them are magnetic, but as mentioned that doesn't prove it either way.

Has nobody got a ct26 which is 100% not a ceramic one, who could show what the turbine looks like, or test if its magnetic?

Did uk st185's come with a steel/inconel/whatever turbine wheel?
USA mr2's did, I might ask on a us forum

[Danbob]

Or some photo's of another 100% certain standard ceramic turbine might help as well, surely somebody will have that kicking about?