Quote:
Originally Posted by lucid
That car is 5 model years old. You said that they upgraded its rotors to 15" and shipped it with matching pads.
|
I did not choose it because it is old. I chose it because I could find all of the necessary data. I agree the the latest Porsche systems are likely much better.
Quote:
Originally Posted by lucid
How about the ZR1? I know it has 15.5" Brembo rotors up front, but I couldn't find any data on thickness or volume.
|
I heard the ZR1 uses rotors straight off the Enzo.
Quote:
Originally Posted by lucid
How did you arrive at 4" for the same mass? Clearly, the c values are higher in the products that are shipped today. At least for the Brembos. The SGL data seems less certain. Their website says c=800, and their SAE presentations says c=1350. I am not sure how to intepret that.
And, again--I've repeated this several times--they don't even have to weigh the same for the thermal performance of the CC rotor to be superior. According to the specs for the CSiC materials that are being used in the rotors TODAY, you need increase the CC rotor volume/mass by just 37% for the mass x specific heat capacity ratios to be equal. Anything beyond that hands the advantage over to the CC rotors.
|
Not the best estimate. That was for equivalent mass, not equivalent thermal mass. For equivalent thermal mass with the lower c you would need 2.5 thickness or a 22/19 diameter (or something in between). For the improved c you need a modest 1.5 thickness or a 15/12 diameter. Funny how the latter looks to be right about where things have gone, 15" OD and perhaps a bit thicker than "normal"!
Quote:
Originally Posted by lucid
I'd be happy to work on a computational model with you on this one.
|
That would be fun. We still need some concrete material (pad and rotor data) to make the models truly meaningful. We'll also need conductivity as a tensor (ugh). My thoughts were just a transient thermal analysis leaving all thermal expansion and stress effects out of the model. As well I would assume a non-rotating system with a annular patch power input, initially constant then later allowing it to ramp down with vehicle speed. I'd like to have an estimate of this difference between peak and spatially averaged temperature results and a model can do that. It would also test conservation of energy. My company was recently acquired by ANSYS so I will have access to a great deal of best in class tools in the structural, thermal and fluid domains (ANSYS bought Fluent (CFD) a while back as well). Cheers.