Titanium Rotor

[Kenhk]

Anyone heard about Titanium rotor ?
www.zmibrakes.com
Appreciate if anyone know about it.

Thanks for sharing

Ken [img]images/graemlins/greyrs4.gif[/img]

[Mog]

I posted this about a month ago and no one showed any interest [img]images/graemlins/frown.gif[/img]

Mog [img]images/graemlins/s4anogaro.gif[/img]

[Kenhk]

Hi Mog,

Pls tell more.
Is it proven technology and supplier ?

Thanks,
Ken
[img]images/graemlins/greyrs4.gif[/img]

[Mog]

I'm afraid I just found the web site like you and posted it up to get some opinions with no results.

Mog [img]images/graemlins/s4anogaro.gif[/img]

[runrowsam]

I'm not a genius, but I thought I'd add my tuppence worth. The trouble with using titanium would be it's friction coefficient, and possibly heat issues. Firstly, the friction. They claim to have used some fancy chemical etching which basically roughens the surface, but I'm not sure about once you've work down that initial surface. In theory a rough pad surface should maintain a reasonable level of roughness on the disc, but it will smooth off a bit.
Then the temperature factor. Just like in carbon brakes, titanium needs to get pretty hot in order to be any good. As it heats up it expands unevenly, hopefully increasing the friction coefficient, but cooking the system a bit. So long as you use the right fluid it should be fine. But the discs will run a lot hotter, so I'm unconvinced about cold mornings and the usual low initial temperatures.

However it does have its good points of course. The discs are much stronger and lighter than steel, so they will take a lot more stick than normal steel discs - always handy on a big car like the RS4, especially for track use. They should also theoreticall last a bit longer than steel discs. They are lighter too, which lowers your unsprung weight, allowing better steering response, and also road contact if there's enough of a difference. It really is amazing the difference that can result from lowering your unsprung weight.

Anywho, that's me about done. Feel free to tell me I'm talking crap, since I'm only going on my basic knowledge of titanium. That's what I like to call "blag physics". Too cool for school [img]images/graemlins/bigwave.gif[/img]

Rock on
Sam [img]images/graemlins/thumbs.gif[/img]

[Kenhk]

Hi Sam,

Thanks for your input.
It's definitely lighter/harder. But I don't know about the coating, elongation ?

Anyone knows more or did anyone even try it ?

Have fun. [img]images/graemlins/beerchug.gif[/img]
Ken
[img]images/graemlins/greyrs4.gif[/img]

[kiwi_mtm]

carbon composite for me please.

[Jon]

I was having a chat with a porsche enthusiast the other day and it appears a lot of GT2 owners are swapping the ceramic ones for steel ones as there are issues with them at the mo.

[Golich]

Hhmm interesting..come on someone with loads of dosh buy them and give us a review. [img]images/graemlins/smile.gif[/img]

[runrowsam]

Sounds a bit dodgy. I've had a brief go on the Porsche ceramic brakes and I thought they were AWESOME. It was a 6 month old 911 Turbo with the GT2 upgraded system on it. By 'eck did it stop. All Porsches have good brakes but those ones really did take the piddle. Needed to get a bit of heat in them, but then they were fantastic. Zero fade, good feel, and unbearable retardation forces. I'm guessing these problems you're referring to are long term, maintenance related, as I can't see how you can have something like that that NEEDS to have its nuts ragged to bits, without destroying them every 5 minutes. Much the same issue as I fear these titanium chappies might have.

Come on somebody, prove me wrong!

Rock on
Sam [img]images/graemlins/thumbs.gif[/img]

[Kenhk]

Other than braking force/fade, how about the weight of the system ? The producer gives emphasis to the light weight of titanium rotor and result more hp on wheels. Also it is easier to brake !

Any idea for the weight of ceramic ?

Ken
[img]images/graemlins/greyrs4.gif[/img]

[SaabTuner]

Titanium isn't THAT light. Here's some info:

Density
Ti: 4.51 g/cm^3
Fe: 7.86 g/cm^3

Melting/Boiling points:
Ti: 1668/3260 degrees C
Fe: 1536/3000 degrees C

Coefficient of linear Thermal Expansion:
Ti: 8.41E-06cm/cm/°C (0°C)
Fe: 1.176E-05cm/cm/°C (0°C)

Thermal conductivity:
Ti: 0.219 W/cmK
Fe: 0.802 W/cmK

Thermal Capacity:
Ti: 0.52J/gK
Fe: 0.44J/gK

Rigidity:
Ti: 44/GPa
Fe: 82/GPa

What does all that mean? Well titanium does expand about 60% less when heated compared to Iron, and stores slightly more heat, but Iron is TWICE as rigid, conductcs FOUR TIMES more heat (which is far more important that how much it stores), and melts at almost as high a temp.

Here's three parts to the elastic modulus of both metals:

Ti:
Bulk: 110/GPa
Rigidity: 44/GPa
Youngs: 116/GPa

Fe:
Bulk: 170/GPa
Rigidity: 82/GPa
Youngs: 211/GPa

And here's the hardness of both metals:

Ti:
Brinell: 716 MN m-2
Mohs: 6
Vickers: 970 MN m-2

Fe:
Brinell: 490 MN m-2
Mohs: 4
Vickers: 608 MN m-2

This shows that titanium is harder than Iron (even if not nearly as rigid), which may be good for rotor wear, but probably not for coefficient of friction. (which cannot be quantified as the pad compound would be part of the equation)

Anyway, hope that's helpfull. [img]images/graemlins/smile.gif[/img] This of course does not address certain Iron and Titanium alloys which may have varying properties.

Cheers,
Adrian W

[SaabTuner]

I recall a Saab concept car used Aluminum rotors. Sounds crazy but here's some info to consider on properties of Al vs. Fe:

Thermal Conductivity:
Fe: 0.802 W/cmK
Al: 2.37 W/cmK

Rigidity:
Fe: 82/GPa
Al: 26/GPa

Coefficient of Linear Thermal Expansion:
Fe: 1.176E-05cm/cm/°C (0°C)
Al: 2.39E-07cm/cm/°C (0°C)

Summary? Aluminum is much less rigid (which may have been the ultimate reason it wasn't used), but it conducts 3 times the heat of Iron (10 times as much as Titanium), and oddly enough expands LESS than Iron when heated. If appropriate pads were developed and implimented it could be a very effective rotor substance for street cars. Though race cars would be better off with Ceramic or Carbon because of the extreme heat.

Cheers again,
Adrian W [img]images/graemlins/smile.gif[/img]

edit: I decided to add Tungsten (Symbol W) to the list of possible materials. Here are its properties:

Thermal Conductivity:
Fe: 0.802 W/cmK
W: 1.74 W/cmK

Rigidity:
Fe: 82/GPa
W: 161/GPa

Coefficient of Linear Thermal Expansion:
Fe: 1.176E-05cm/cm/°C (0°C)
W: 0.460E-05cm/cm/°C (0°C)

Hardness:

Fe:
Brinell: 490 MN m-2
Mohs: 4
Vickers: 608 MN m-2

W:
Brinell: 2570 MN m-2
Mohs: 7.5
Vickers: 3430 MN m-2


Tungsten transfers TWICE the heat of Iron, is TWICE as rigid, expands HALF as much when heated, but also FIVE TIMES harder making it possibly much slipperier, and it's two and a half times heavier than Iron. Not to mention a lot more expensive. Just food for thought.

[Paul-RS]

Funny you mention ally discs.

my mate runs a Lotus elise (road car)

he has got Aluminium metal matrix brakes or some similar name.

costs of pads and availability are horrendous, and lotus dont fit them to elise's anymore, but the pads supposedly replace the material on the disk AND create Zero dust.

[SaabTuner]

Airplanes often use Beryllium rotors which conduct almost as well as aluminum but are LIGHTER than aluminum and much much stronger. They also don't melt as easily. And suprisingly, copper conducts heat almost TWICE as well as Aluminum does, is harder to melt than aluminum, stronger, and only weighs just slightly more than the stock Iron. If you compare it to Iron it transfers five times more heat and only weighs about 10% more! Anyone try a copper rotor? [img]images/graemlins/laugh.gif[/img]

Cheers,
Adrian W