Are Ceramic Turbine Wheels Really That Bad?

[R31Nismoid]

NO you read right, gtr turbos kill motors, wheras gtst turbos dont. Could be due to the manifold design, cam timing, maybe because the gtr turbos are smaller, they spin harder and fly apart harder, who kmows.

Ah but they do

Two Vic people have killed them, was the shitty series 2 turbo, compressor wheel came off (when the rear let go, unbalanced the shaft) and then the comp wheel minced the motors... yes - it did make it past the cooler!

I couldn't believe it either, its just a very uncommon occurrence

[GTRgeoff]

Perhaps its counter intuitive from a fluid flow perspective, but if we consider the momentum of the pieces of turbine as the wheel lets go - those pieces are mostly flying off toward the manifold against the direction of fluid flow, due to the shape of the turbine lead in. So short manifold = not enough time for the exhaust to slow the shrapnel down and it makes it all the way pass the exhaust valve.

Just a theory.

Actually the pieces coming off have to contend with the scroll shape of the housing and the direction of travel of the turbine so even with the energy release there has to be more happening to create such a reversion pulse that particles enter the engine.

Considering that this doesn't occur in every case it can't be contributed to just the destruction of the turbine, which gives me greater confidence that in the cases where ingestion occurs some degree of blocking by the turbine wheel has to be present. Then it is plausible that pulse inversion causes a negative pressure spike dragging the material into the cylinders. Similar to extractor function, just in reverse.

Alternatively there could be a relationship with exhaust back pressure from the turbo still running that causes flow reversion in the damaged side.

26 has three runners per turbo @ much shorter lengths and less bends.

20/25 has six runnders per turbo @ much longer lengths and harder bends.

I don't think it takes a genious to see why more ceramic can get in the 26 cylinders... either engine will get a taste of dust be it 25 or 26 TT or single

There are a couple of runners that are very close to the turbo so the explanation has to be a little more complex. I'd do some calculations on the mass flow, impulse reversion and relative densities but I'm retired so cbf.

We've all seen compressors have a munch on the housing, which being ally will absolutely go through the pipes and IC causing engine damage but this discussion has little to do with that so we should avoid getting sidetracked.

[Brezza]

i would've kept my ceramic ones, great for spooling up quickly.

but yeah, problem was that they were old and the rear wheel broke right off.

just give manufacturers time to perfect the way they are attached and they'll be much better than heavy steel wheels