Ceramic Stockies

[No one]

hey guys

just had a another question

with the stock ceramic turbos ive heard that its impossible to know when there gona blow up but it will happen

everyone sort of says its the heat that kills them

like if ya run a bar boost or new cams etc etc

i was thinking today that maybe its the oil lines clogging up over time and blocking

leaving no oil going to the turbs and then just burning away till a ceramic explosion

what do you guys think??

or am i just talking shit

g

[R31Nismoid]

Its proven that the shaft speed along with the heat causes the wheel to split from the shaft and thus, cermic wheen out the end.

Its cermic and does not last like steel

Its not oil lines clogging up.

[bogcock]

Its proven that the shaft speed along with the heat causes the wheel to split from the shaft and thus, cermic wheen out the end.

Its cermic and does not last like steel

Its not oil lines clogging up.

what are you, a f**king engineer ay!

[R31Nismoid]

Just about

[bogcock]

Just about

ur funny.

i actually am an engineer. and its not the rotating speed, its the heat. the excessive shaft temps cause the wheel to split, as the shaft expands and pushes out on the wheel.

just to clarify.

cheers

[R31Nismoid]

Are heat and rotating speed not related to each other?

[bogcock]

if you could keep the exhaust wheel and shaftat an even say 25oC, the wheel would not explode.

if its pumping 15psi @150,000rpm for 30 seconds @ 1200oC it will die fast due to expansion

if its pumping 15psi @150,000rpm for 10min @ 10oC it will stay together as long as the temps are even, and consistent

[Cubes]

In short,

Aim to keep those EGT's down.

What raises EGT's one engineer may ask another?

Reduced Timing

Detonation

Lean mixtures

off topic..

Nizmoid.. Get your hand off it. hehe

Thats disturbing.

[Quinny]

A ceramic wheel or shaft should be more heat tolerant than a steel one. Cermic pieces are fired at over 1000*C, steel won't take that. I would think that it would be the pressure of the forces pushing a ceramic shaft at very high rpm that would cause ceramic to crack, where as a steel blade will be much more tolerant than these forces.

Just my 2c.

[bogcock]

In short,

Aim to keep those EGT's down.

What raises EGT's one engineer may ask another?

Reduced Timing

Detonation

Lean mixtures

this is true, but unfortantly as you will know, the turbo relys on hot expanding gasses to operate efficiently not just gas velocity, so its a bad circle of ceramic death..lol

[Cubes]

A ceramic wheel or shaft should be more heat tolerant than a steel one. Cermic pieces are fired at over 1000*C, steel won't take that. I would think that it would be the pressure of the forces pushing a ceramic shaft at very high rpm that would cause ceramic to crack, where as a steel blade will be much more tolerant than these forces.

Just my 2c.

And how does one bond the ceramic to the shaft.. This is where the problem lies, its not a ceramic shaft.

[09ONE_32]

I was under the impression that the wheel departed the shaft because of excessive heat, which causes the material that joints the ceramic wheel to the shaft to fail.

Not suggesting that I am right, but just what I have been told.

Beat me to it. Had to have a piss while typing my post.

Edited June 19, 2006 by 09ONE_32

[Quinny]

Interesting question, how does one bond ceramic to the shaft? Is the shaft ceramic also?

[bogcock]

make a ceramic wheel and shaft... but hmmm, how to fix it to the comp wheel... think of this and make a mint..haha

unfortunatly the shaft would break on the first compressor surge

[bogcock]

I was under the impression that the wheel departed the shaft because of excessive heat, which causes the material that joints the ceramic wheel to the shaft to fail.

Not suggesting that I am right, but just what I have been told.

this is half correct.

the reason is the wheel is pressed from the inside out by the shaft, and the material that bonds the wheel to the shaft weakens.

next time you flog the turbo, the wheel expands BEFORE the heat can transfer to the shaft and evenly heat the unit, causing the wheel to "fall off"

[mad082]

Are heat and rotating speed not related to each other?

no they aren't. boost pressure and heat are related. the higher the pressure, the higher the temp. you can increase airflow and have the same pressure and it won't raise the temp.

also having a restricting exhaust holds in the heat more. a more restricting exhaust has a higher pressure in it, which creates more heat.

[GTRsean]

At least you'll never have that problem with N1's!!

Interesting that nissan also had nylon compressor wheel and ceramic turbine wheel on the r34 GT-T.

[bogcock]

At least you'll never have that problem with N1's!!

Interesting that nissan also had nylon compressor wheel and ceramic turbine wheel on the r34 GT-T.

nylon comp wheel was also for quicker spool but the main reason was for the bearings. a lighter rotating mass lightens the load on bearings, which stretched the service life!!!

[paulr33]

it was probably cheaper and lighter in wieght, which means faster response.

its like oem would be worried about how it went at 12psi for extended periods of time as this was beyond the factory scope/specs. sure they would have tried it for a few laughs, but its well within acceptable for factory configuration

[GTRsean]

One of the HPI dvds had their R34 GT-T project car blow one up on a track day but they were sort of expecting it to after all the mods they did. Was funny though.

On guy who lives near me has a NOS system on his GT-T and the stock turbo is still hanging in there.