21K95RX7

just wondering if anyone has tried fabricating a titanium wheel for their turbo? i heard titanium is stronger, and is 30% lighter than comparable size wheels. i dont know if this equates to 30% faster spool. just imagine if you changed a t88 wheel for a titanium one. lets say on average (havent gotten hard figures) its starts boost at 4800rpms and you knock that down by 30% you get spool up at 3360. for the twin guys like me who are looking to go bnr\'s one day. i believe the bnrs start about 2600 rpms (please dont flame me if wrong) so if you replace the wheels they could possibly start boost at 1820 rpms. like i said before im not sure if the weight loss equates to 30% faster spool. but i have read about supra guys going to aluminum wheels and evo turbo makers using the titanium.

mibad

Now that would take some serious skills. Better let me cryo treat it after you get one. : )

21K95RX7

lol no problem bro, just need to find someone who could make them to spec

mono4lamar

iTrader: (32)

for the high cost... i wouldnt want one. thats my take, sorry

true_rolling

What kinda price range are we looking @...?

21K95RX7

have you seen the prices? really not that much more expensive, you should really do some research on it before you shut out the possiblilities, of noticably less lag and higher top end power

21K95RX7

i found a place that does custom turbo chargers boostplanet.com im gonna call them and see what they could do

21K95RX7

now this is an evo turbo maker and the turbo is only 825 usd (not sure of their quality) but thats not that expensive

This is the EVO6.5 RS T.M.E Titanium shaft turbocharger with larger 10.5cm^2 Turbine housing. Fits all EVO4-EVO8 cars and offers a larger, less restrictive turbine housing made in A3N material that is less affected than the standard F5 material by anti-lag systems and elevated EGT’s.
The Titanium Aluminide turbine wheel and shaft is 33% lighter than the standard Inconel 713C turbine wheel and shaft. This enormous reduction in the rotating assembly inertia is Mitsubishi’s response to the demand for ever increasing shaft acceleration rates and decreasing turbocharger spool-up. The Titanium Aluminide material is also significantly more stable at 1600F than Inconel 713C.

The effect of increased lag of this larger exhaust housing is more than offset by the increase in spoolup provided by the lighter rotating assembly, resulting in faster than stock EVO8 turbocharger spoolup with increased top end power. Our AEM EMS datalogs show a .3 second boost recovery to 25psi during shifts while producing in excess of 370whp through the stock intercooler!

21K95RX7

didnt know this but the stage 3 mopar kit for the srt4 uses a titanium wheel in the turbo

21K95RX7

damn i thought there would be more interest in this

zxert

nm editer.

dgeesaman

iTrader: (7)

I have to be honest - there is probably very good reason why they aren't already using titanium. I'll have to go research it and try to determine why.

Dave

bajaman

^ there IS a very good reason.....titanium does not hold up to the heat as well as Inconel. Ti is great for something that is not expected to last like we expect turbos to last. 'Course, if you've got the money....go for it!

The company I work for has made titanium turbines for various applications for years. Of course, we charge something like $15K for a turbine.......

dgeesaman

iTrader: (7)

Makes sense - quick punchy spool is mostly a thing for street applications, but in that case you also need very long lifespan.

What happens to the Ti? Loss of strength, galling, creep?

Dave

21K95RX7

im sorry but titanium has a melting point of over 3000 degrees farenheit. if it wasnt expected to last then why does mitsubishi use it in their turbos from the factory, and its used by dodge in their stage 3 turbo. 15k for a turbine??? for what application? im talking about cars here, i didnt know the stage 3 was 15 grand that was supposed to be sarcasm. please disprove me with facts not opinions

21K95RX7

dave hes talking out of his ***

rynberg

Who's talking out of their ***? Your "theory" that a 30% lighter wheel will spool 30% sooner (several hundred rpm sooner) is simply ridiculous. There are many factors that determine spool time, rotational inertia only being one....

In any case, why bother using them on stock twins, which already spool almost instantly and make full boost by 3000 rpm?

dgeesaman

iTrader: (7)

Bajaman does NOT talk out of his ***.

A turbine is not a turbo. However they experience similar environments.

Melting temperature does not provide much information about the performance of a material at elevated or high temperatures. Strength can decrease significantly, or it can become less rigid or even plastic. While Titanium and Ti alloys work well at 'elevated' temps compared to cheaper lightweight materials like aluminum, it peters out and loses strength above 600-1000F. They call this 'elevated' temperatures. Turbos need to withstand much higher temps - so-called 'high' temperature service.

In high temp environments like a turbo, materials like Inconel and other nickel-base superalloys do better. Though these materials are more dense than aluminum or titanium, these would require thicker blades, and thick blades are not as efficient as thin ones.

Dave

21K95RX7

if you read my post i said that i dont know if it equates to a 30% spool up time, and yes i do realize that there are more factors that go into determining boost. oh and talking out his *** was meant for the baja guy. you make a good point of not using them on the bnr\'s or stocks but what if you put it in a t88? you could almost get the boost response of a apexi rx6 turbo, and have alot more power potential.

rynberg

Again, you are talking out of your ***. You have zero clue of what the effect of a titanium wheel in a T-88 turbo would be. You are making it up out of thin air and promoting it as near fact.

Until you start showing calculations proving your "theories", you are just spinning your wheels...no pun intended.

bajaman

Not talking out my *** here, buddy. I've been either machining or supervising the machining of these things for 28 years. So shush now, okay? No one is saying that a titanium impellor wheel is not possible and hasn't been done. What needs to be understood is that Monel, Inconel, and Inconel X are simply the best all around choice for the MAJORITY of applications.

And the $15K is for one small single stage stator used in a GE APU.

21K95RX7

first off sweet baby jesus dont ever tell me to \"**** off\" a very wise person told me to always know who your talking to before you say something like that. also, when i say \"but what if\" simply implies that im theorizing not passing it off as fact. and if you read my cut and paste of the tests of that companies turbo with the ti wheel it will \"prove\" my theories. .3 second boost recovery to 25psi during shifts while producing in excess of 370whp through the stock intercooler! .3 is 30% of a second isn\'t rynberg? also, dave the titanium wheels have thinner blades than their steel counterparts.

California Dreaming

I'm interested in seeing where this goes, my bet is on the long list of locked threads.

I must say, the idea is thought provoking to say the least and I'm sure someone else must have pondered the same thing in the past.

-Neal

Tenacious

the dude I bought my car from is a cancer doctor, his brother is a nasa rocket scientist....apparently my turbo's were rebuilt by his brother, it'd be kickass if he used some crazy alloy on my turbo's! I cant wait until I can afford new turbo's to check this out...

Either my turbo's are crazy cool, just regular normal, or jerry rigged to ****....hmmmm /ponder

dgeesaman

iTrader: (7)

If you're shocked by the harsh reaction of several engineers/scientists/manufacturing specialist, maybe it's because your question came off as really ignorant. Your response of "talking out of his ***" was the beginning of the aggression. If you hadn't been aware of that, you need to pay more attention to what you're putting out.

As far as I can tell, Bajaman is the only one here with significant hands-on experience with high temp turbine parts. Some of the rest of us have the training to know that the idea of applying Titanium is far from original and that there are many potential issues. In my industry, we generally don't use Titanium above 300°C - the Inconel becomes the winner.

It's fine to armchair engineer some ideas, but when you pose the question I think you should take the responses seriously. Nasa, GE, Rolls-Royce, etc have been testing materials like titanium and inconel for decades. That's a trustworthy body of knowledge.

As for the thickness of the blades, I was referring to the fact that at high temps Titanium really loses strength, so you would need more of it to handle the same job. This would not be the case at lower temperatures, but since rotary exhaust is extra hot it's even more important.

Take a look at sources like this: http://www.timet.com/all-p03.htm and you'll see service temperatures ending at 650°C. Inconels like X750 have service temps up to 800°C. (http://www.hightempmetals.com/techda...elX750data.php). And I didn't even consider what corrosive effects the exhaust may have on the metal, or if they part could be manufactured. There is still massive interest and research going into developing better materials for these applications - and in fact Titanium-based ceramics (Gamma Titanium Alumnide for example) are in the mix. But they aren't here yet, and they are very expensive. And they aren't "titanium" - they are really what we call ceramics.

A metallic titanium turbo might resist creep well enough work in low-cycle applications where you can force down the EGTs (e.g. drag racing where you can use water injection and the turbo's lifspan is measured in minutes, not hundreds of hours). That is drastically different than track and street turbocharging at EGTs put out by a rotary.

Dave