Titanium Compressor.

SmokinCAT

SmokinCAT

Cheap and Easy.
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Sep 13, 2008
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Curious what purpose these serve over the standard aluminum compressor wheel?
 
The he561 titanium wheels are heavy as hellllllllllll.
 
It takes more heat and weight doesnt matter in industrial engine. No chargecooler between stages ?
 
Mainly fatigue is why they use TI wheel and yes it could be HP application like on the Cummins QSK series and these have after coolers between the stages but like mentioned before every application that goes over critical cycles on the turbo side of things there could be a chance that TI is used from forklifts to city busses.

For motor sport do you need TI? Bit heavy I would say and for pulling sport in Europe it’s banned out as being to dangerous. You could speculate about other benefits bit I can not find any unless you want to run hi pressure difference for a long time but chance is that your alloy compressor cover (if there is one) will chance shape under hi temperature messing things up.
 
Leiffi said:
It takes more heat and weight doesnt matter in industrial engine. No chargecooler between stages ?
Click to expand...

Nothing between stages that I can tell with what engine information I can find from just the turbo number. LP turbo is a HT100.

No alloy cover here, the cover for this turbo is cast iron as is almost all others use with Ti wheels in the large frame holsets.
 
The VGT titanium wheels are identical in design to some of the MFS aluminum wheels. The CAT ti wheels are usually a full blade design. No split blades. The strength during high cycling makes sense. The part I cannot figure out is one would think the bearings would take a bigger beating with all of the added mass but all of my cores with ti wheels are tighter than heck. Whether it be Holset, Garrett, or the ti borg stuff on some of the Macks.
 
I'm curious about the clearances required, I suppose the aluminum housings expand at a higher rate than the Ti wheels

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biggy238 said:
I'm curious about the clearances required, I suppose the aluminum housings expand at a higher rate than the Ti wheels

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Click to expand...

I will check some clearances but this one is a cast iron cover for containment if the wheel were to explode.
 
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One on the right is an older H5 wheel, less than a millimeter difference in inducer size but exducer is quite different.

Ti wheel looks to have a bit more angle to the blades, someone a bit more versed in the lingo might be able to explain how there will have different characteristics.
 
Almost all of the time, Garrett uses Ti wheels on the secondary in a compound setup due to the air charge temperature. I can't recall off the top of my head, but the aluminum wheel long-term service temperature is lower than you would think for commercial apps...like around 300F. Cast/ductile iron covers are needed for containment...the heavier wheel, if it ever let go (say due to a casting defect) would pulverize a cast Al cover.

Ti wheels are also used where corrosion by salt (marine) has caused issues with Al wheels.

As for the weight, yes they are heavier, but remember the turbine is an an overwhelming % of the total rotor mass. And you see in many cases for commercial vehicles where the turbine seems rather large (to us in the hi-po world), the compressor weight is just not a big deal.

Titanium's coefficient of thermal expansion is very low....which is fantastic because the housing is always going to grow more than the wheel....so as you flog it...the clearance goes up, which is generally OK for commercial vehicles.

And yes the fatigue life is 6X or more of the same aluminum alloy wheel.
 
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I remember the Ti being preferred in aerospace because of the lower coefficient of expansion, I was thinking that an aluminum housing would expand to the point that the clearances caused a loss in efficiency.
Then again, maybe not

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biggy238 said:
I remember the Ti being preferred in aerospace because of the lower coefficient of expansion, I was thinking that an aluminum housing would expand to the point that the clearances caused a loss in efficiency.
Then again, maybe not

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Click to expand...

Right at .020" clearance.
 
SmokinCAT said:
No alloy cover here, the cover for this turbo is cast iron as is almost all others use with Ti wheels in the large frame holsets.
Click to expand...


Going to want that cast iron cover when your the passenger in a cabover truck sitting on top of that charger when the driver is flogging it! Lol. Or at least Kevlar underwear.
 
So outside of it being heavier and containment if it goes, a Ti wheel theoretically would be preferred for a HP turbo in compounds?
 
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