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Oggie

Is the T25G Turbo Steel or Ceramic?

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Yep, the boost sensor is only in the first series of S14's and is in the intercooler piping just where it turns 90 degrees after heading across the top of the radiator up towards the tb. On the later S14's you were left with a small flat blank section that looks like it was made an extra injector, water spray etc

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dudes we are tying to prove dumb *milkshake's* wrng about t25's

Why the anger, dude? I've asked a question that I'd like an answer to, with a high probability of being correct. There are so many "experts" on the Internet, it is hard to know who is right.

 

In any case, I have now got the definitive answer, straight from Garrett (this is a straight cut and paste from e-mail's I received from two Honeywell/Garrett representatives): Quoting Geoff Watson (Honeywell Australia):

"Hi Peter, there are several iterations of this older model and there were a couple of different suppliers.

 

In general the turbine wheel is a high grade, high nickel content wheel casting and the compressor wheel is an aluminium casting. Garrett have used some ceramic turbine wheels for Nissan production.

 

Most of the import 180SX s and Silvias imported into Aus are alum comp wheels and high nickel turbine wheels."

 

Geoff Watson also CC'd the e-mail to Masao Haneishi (Honeywell Japan), who confirm this:

 

Yes, 180 SX used hi Nickel ally turbine wheels.

Only applications that used the ceramic turbine wheel is a Skyline GT-R.

 

So there we have it. Definitive proof that the T25G doe not have a steel exhaust wheel. :lol: Rather it is a high nickel content alloy and DEFINITELY NOT CERAMIC.

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is the GTR ceramic?? isnt it only some GTst's? T3?

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The T3 skyline GTS-t turbos definitely have ceramic wheels, but maybe there's a ceramic T28 version for the GTR too.

 

I just measured the resistance on a T25 turbine. Dead short, ie it's made of metal.

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Just a little off topic now: does that white stuff in the exhaust part of the turbo mean the engine has been detonating AND running lean or what?

does anyone know the answer to this?

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it could mean a couple of different things, like excess heat, runnin lean etc etc...

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or just different fuel additives..

 

It's too variable to diagnose the engine's running habits from :)

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i give up i em sick of ppl asking and aurging FFS GO AND GET A T25G or a T25 AND HAVE A LOOK FOR UR SELF.

 

 

think wat eva the f**k u want but maybe when u lrean that they are not steel come back and talk it up like u know ur shit.

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i give up i em sick of ppl asking and aurging FFS GO AND GET A T25G or a T25 AND HAVE A LOOK FOR UR SELF.

 

 

think wat eva the f**k u want but maybe when u lrean that they are not steel come back and talk it up like u know ur shit.

You didn't read the thread, did you? I posted the definitive answer from Garret themselves (above).

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and based on the electrical conductivity of a T25 turbine I have right here it is made of metal (this happens to be high nickel content steel according to garrett).

 

Another clue can be found by looking at the blades of a damaged turbine, and by doing a simple experiment.

Take something ceramic, like a coffee cup. Hit it with a hammer.

Notice the effect? It seems to break into many pieces which, when examined closely, have all broken sharply, and none have become bent at all.

Next bash a metal milkshake cup with the same hammer. You will notice that it doesn't shatter, or even break, but bends out of shape a bit.

 

I have two different damaged turbines here as it happens.

One is a ceramic turbine from a VG30 turbo. It has broken off the shaft and smashed itself up in the turbine housing.

On examination, the edges of all the blades have snapped off, and nothing can be described as bent.

The other turbine is from the aforementioned T25, which suffered a major bearing failure.

The edges of the turbine blades have worn down a bit, but the ends have actually bent very noticeably.

 

I'll post pics tomorrow if I get a chance.

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I have a T25 I pulled from a CA18det

Its a steel wheel, tested with a multimeter, and scraped with a knife. I can scratch / shave the wheel.

 

I have a T25g from an SR20det

It has ceramic wheel, tested with a multimeter and scraped with a knife. I cannot scratch or shave the wheel.

It also appears that the wheel and the shaft are one piece.

 

What is the highest boost someone has run on a T25g successfully?

My CA18det ran 15 that would drop down to 12 by redline, but it took me a year to blow that turbo.

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Ignoring the unnecessary 9-year-old-thread-resurrection, my old T25G had a metal wheel, so varients of the turbo probably exist.

 

12psi is the accepted efficiency limit of the T25G, not because it can't make more boost prior to self-destruction, but because beyond 12psi it heats the air too much. Hot air is less dense and can cause detonation, so your gains are actually fewer and risks higher, hence it being the limit of efficiency for that turbo. A high-flowed T25G or T28/25 can obviously perform better, but these days people just buy a 3071 or whatever. With so many turbos on the market, why bother upgrading a stock one for similar cost to a new unit?

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Foxtail,

 

Either your T25G is in fact a T2 GTR Turbo or a GTS-t turbo with a T2 housing or your turbine is steel....

There are NO Silvia/180sx turbos with factory ceramic wheels.

 

Anyhow as pmod has stated once you start running more than 12PSI there are no a lot of gains to be had as the compressor charge will be quite hot and power wise you'll be going backwards.

Edited by D_Stirls

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