Where to begin!

Readers,

First off, I would like to introduce myself. I am a car enthusiast, no wait, an aficionado. I find the engineering, passion (and sometimes, the manufacturing) amazing. Some base their liking of automobiles by the lines and the artistic concepts expressed through vehicles. I on the other try to look deeper, at individual components and the basis for why things are the way they are. However, the true reason for this blog is to keep myself asking why and to assist (well, to try) my mind from becoming a non-progressive, stagnant human organ of post-graduation laziness. I will give my earnest attempt to post 3-4 blogs a week which may be more than I'm asking for. But it really depends on what I see at work, so the more kickass stuff I see, the more I will blog. So, lets dive into things!

My first topic that I would like to discuss are ceramic brakes. Nowadays, ceramic pads and rotors are commonplace with super car manufactures and more recently, with Nissan under the debut of the GT-R Spec-V (which we don't have in the states yet). Ceramics (from what I remember as a student) is the abnormally high concentration of carbon mixed into materials. So how can a commonplace steel rotor be improved by a ceramic rotor. Well for one, lets imagine that a steel rotor is like a sponge cake. Our sponge cake has tons of air pockets most likely full of oxygen and nitrogen (the stuff in the air). Now, instead of a sponge cake lets say our batter of a carbon and steel mixture was used to create a pound cake. The pound cake is packed with less air pockets, however, since our pound cake is a mix of two things, those old air pockets are now full of carbon.

You see, carbon is one of the hardest and smallest particles on the face of the planet. Carbon makes up diamonds, diamonds! There's a reason why "diamonds are forever" and that you can cut or vandilize just about anything with a diamond. But you may be asking, "wait a minute, carbon makes up coal, and coal just falls to pieces when I burn or throw it." But did you know that artificial diamonds can and are made by highly compressing large amounts of coal into small "fake" diamonds? And the mixture of carbon into steel gives us the ceramic rotor.

So, in reference to the cake metaphor, the ceramic rotor is stronger. But what about weight? Due to carbon's strength, less iron can be used to manufacture a rotor and that saves weight. This produces a rotor that is lighter and stronger. And since these air pockets (which are sensitive to heat and cause expansion when pedal pressure is applied) are full of carbon, there is less air and a smaller amount of expansion under hard braking. Last but not least, this reduces rotating mass which aids in later braking and quicker acceleration.

However, due to the reduction of friction (which is common with ceramics as ceramics have even been used over steel in ball bearings), the rotors are pretty shitty in the cold. The pads and rotors thus have to be "warmed-up" before aggressive driving and have a key operating temperature for optimum performance. With the reduction of friction though is the increase in longevity (which is also aided by the added strength) and the technician at work tells me Porsche ceramic rotors will probably last longer than the cars themselves!

But is not worth it in the end? Of course! A rotor that is significantly lighter than its steel counterpart while improving off-the-line and out-of-the-corner performance and improved braking is a wanted must for any enthusiast. However, the price of true ceramic rotors and pads come at a cost. Supposedly, the cost of the ceramic rotors and pads on the GT-R Spec-V are a bit under $50,000 for all four corners, but then again we are talking about a 15 inch rotor. On that expensive note, lets look at some real-life ceramic rotors, the ones below are off a coveted 997 GT3 RS at work.


First thing you should notice is the "two-piece" design. The center on this particular rotor is a cast aluminum piece. The use of aluminum allows for a light-weight rotor and great heat dissipation. However, Porsche engineers have taken it to the next level to make sure that the heat created under braking does not interact with drive-line components (wheel bearings, C.V. joints, etc.).

As you can see, the rotor and the aluminum "hat" (center) do not actually touch. Thus, the only thermal exchange can only occur through the pins (shiny, fat "H" shaped things) that hold the rotor to the hat which again reduces the amount of heat exposed to drive-line components. One of the coolest things about this particular rotor is the female threaded pin. It has a small slit through the center of it, allowing for a slight compression when the bolt that threads to it is properly torqued down. Porsche engineers, in all honesty, never cease to amaze me.

On the back face, Porsche engineers have decided to use a TORX style bolt. The only valid reasons that I can think of for using a TORX style bolt is to reduce over torquing and to avoid clearance issues (and possibly because its a German thing). Another cool thing is if you ever had to change the rotor, you simply unfasten these TORX bolts from the drive pins allowing you to reuse the aluminum hats.




These things compared to the two-piece brake rotors we have at work are WAY lighter. I usually struggle carrying around a 350mm steel rotor with an aluminum hat attached but this piece is at least half the weight of that, and larger in diameter! Well, I've written for over an hour now, so I think its time to take a break. Thanks for reading!

-Josh