Transcription
Hello everyone, and welcome! In this video, we are talking about Porsche's innovative new brakes. They call these Porsche Surface Coated Brakes, and they have a tungsten carbide coating on those rotors, which Porsche claims is a worldwide first. And it's not just the rotors that are unique; it also has specific brake pads that go along with it.
Looking at it visually, it's already quite different. It has a mirror-like finish, and Porsche has boldly chosen to use white brake calipers to show off how little dust it produces. So, what's cool about these brakes? Well, compared to iron rotors, they have better braking response and more resistance to brake fade. They have less brake dust without reducing braking performance. The rotor's service life is about 30% longer, and unlike iron, which you can see here, starts to rust, this surface won't rust. So, you know, after a day driving out in some rain, you come home the next morning, you look at your car, and the rotor is all rusted. Not with these.
So, how does it do all of that? Let's break it all down. Hold up, stop it, slow down. I'm sorry if your ears are bleeding. All right, so you've probably heard about cast iron brakes. It's the brakes that you'll find on most cars out there. And perhaps you've heard about carbon ceramic brakes. They're super expensive, they're lightweight, but they're extremely fade-resistant, which makes them great for racing on tracks. These surface-coated brakes are trying to fall somewhere in the middle. They're not nearly as expensive as carbon ceramic brakes, but have performance benefits over cast iron brakes.
For the brake rotor itself, you start with a cast iron rotor, and then the surface is thermally treated, galvanized, and then you spray on a layer of tungsten carbide. It's a wild process. If only there was some tool I could use to help explain it. I'll put a whiteboard anywhere. So, the process is called High Velocity Oxygen Fuel spraying, HVOF. So, the basics of how it works is you mix oxygen and fuel. You have a little combustion chamber here, and then you have a carrier fluid bringing in your tungsten carbide. And so you're combusting and then accelerating that tungsten carbide, so it's getting really hot, and then you're accelerating it to supersonic speeds, above the speed of sound, and slamming it onto that brake rotor. And so you're going to have this super dense layer of tungsten carbide that forms on that brake rotor, and this is only millimeters thick.
Here's what that looks like on a set of calipers. It's barely measurable. It's about the width of a human hair, and that's all you have until you have to replace your rotor. So, once you wear through that 0.1 millimeter layer, you've got to replace the rotors. And I know everyone's head just exploded in anger because what, I have to replace the rotor after this barely measurable amount of wear occurs? But here's the thing: because this surface is so hard, the wear rate is extremely slow. Porsche says these surface-coated rotors are 30% more durable than cast iron rotors, meaning they'll actually last longer.
This is actually something I have unique data on. So, I did a video with NRS Brakes where we looked at multiple brake pads to compare them, and when I look at the wear data from these tests, one full round of testing saw about 1.3 millimeters of the brake pad worn down, whereas one full round of testing saw about 0.00083 millimeters of rotor wear, and this was on iron rotors. In other words, under this testing, in which case the scenario was pretty severe high-temperature braking, the pads were at a rate about 1500 times greater by thickness than the rotors. And when you think about how hard rotors are, and that they have a much larger surface area to spread out that wear, that makes sense. And the surface of these rotors, the tungsten carbide rotors, is about 10 times harder than gray cast iron rotors.
So, let's talk about tungsten carbide for a moment. It's the same stuff that's used to make cutting tools because it's so hard. So, if you look at the Mohs hardness scale, you have one, which is like talc, which is something super soft, you could scratch it with your fingernail. Fingernails at like two and a half, and then you have the rating up to ten, which is a diamond. And so tungsten carbide is about a nine, nine and a half on that hardness scale, extremely hard.
So, because this rotor surface is really hard, there's not much rotor wear. And because there's not much rotor wear, there's not much brake dust produced. According to Car and Driver, in an interview with Porsche, Porsche was claiming that 70% of brake dust actually comes from the rotors. And so, if you think about the gray iron rotor on a Porsche Cayenne, it can wear one millimeter on each side of the rotor. This can wear 0.1 millimeter on each side of the rotor. So, because you have significantly less of that rotor material actually being removed, you have significantly less brake dust, in this case, about 90% less.
They also require specific pads that were engineered to be able to work with the carbide surface. If you look at it, if you touch it, it's extremely smooth. So, they had to develop a pad that could dig into this very hard surface and still provide smooth braking. Porsche describes the pads as having microscopic anchors. And these are 10-piston calipers up front to ensure that you have a good distribution of pressure across the pad. Seriously, these calipers are massive.
Now, on the front brake rotors, you'll notice these little cracks and dark spots and stuff here on the rotor surface, and this is actually normal. This isn't affecting how the braking works. The reason why this happens is if you start to brake very aggressively, if you're driving this thing very aggressively, you'll start to see these marks on the brakes. And as this is a press car driven by a bunch of automotive journalists, yeah, they're going to be a little hard on the front brakes. So, actually, if you were to drive this thing lightly over time, it might come back. It'll smooth out that surface, and it could go back to looking like those rear brakes with that mirror-like finish.
So, what about braking performance? Well, what's really impressive about these rotors is that they maintain much more stable braking pressures than cast iron rotors. Porsche provided a graph showing the increase in pedal force required as the brake disc heats up. This is done with 0.8 G braking, so very aggressive braking. And you apply stop after stop after stop. After two hard braking instances, the brake temperature is at 330 degrees, rising all the way to 640 degrees by the 13th braking maneuver. And as you can see, the cast iron rotor, the black line, continues to increase as you continue to apply the brakes each time. This means the pedal effort required by the driver to maintain the same deceleration, 0.8 G, increases. So, the driver has to push the pedal harder and harder each time. The PSCB rotors, on the other hand, allow for fairly steady pedal effort. This will lead to a more intuitive feel for the driver, and it won't give you the sensation that your brakes are getting too hot because they can actually handle these hot temperatures.
So, what do the brakes feel like to drive? Well, honestly, I wouldn't be able to tell the difference between these and cast iron rotors in normal driving conditions, and that's a good thing. And versus carbon ceramics, sometimes you'll have where when you brake really hard with carbon ceramic brakes, the first time you do it, it's a little sketchy and a little uneasy, and the car kind of squirms around. But then once those carbon ceramics get hot, the brake feel is really good. And these don't have that. So, with that first really hard initial break when the brakes are cold, it feels just as confident like iron rotors do.
You might reasonably ask, is it actually necessary to have brakes that don't fade on a Cayenne Turbo? And in most daily driving scenarios, no, absolutely not. I suppose you could track your Cayenne Turbo. However, I'm not sure if you were aware, but for the same money, or significantly less, there are much more track-friendly Porsches out there. Now, if you do plan on towing, and this has a towing capacity of 7,700 pounds, then certainly having brakes that don't fade is a bonus. Regardless, the reduction in braking fade is a performance benefit that these brakes offer.
Now, it's fair to wonder, what do these brakes cost? So, the way Porsche describes it, these are going to last about 30% longer versus iron rotors. However, they're going to give you brake fade characteristics similar to that of a carbon ceramic brake rotor, but at a third of the price. So, these come standard on the Porsche Cayenne Turbos. However, if you get the base Cayenne, this is a $3,500 option versus the carbon ceramics, which is a $9,000 option.
Now, for fun, I emailed a Porsche dealership to see what the replacement cost is for the various types of brakes that they offer on the Cayenne, whether that's the cast iron brakes, whether that's the surface-coated brakes, or the carbon ceramics. So, they provided me the total parts cost with tax, no labor included, for pads, rotors, sensors, and I rattle clips and bolts for both the front and rear brakes. So, the standard gray iron rotors, total replacement parts cost of $343.15. The surface-coated brakes that you see here, $11,095.10. And the carbon ceramic brakes were quoted at $32,206.74. $32,000 for a wear item. Now, granted, rotors can last quite some time, but regardless, spending $32,000 on brakes, that's a level of baller I'm not sure I can comprehend.
Now, there's a couple cool things to point out with the wheels off. So, in front of the tire right here, there's a heat exchanger, and so that heat exchanger is dumping out air through these vents, which is trying to push that air out and around these wheels right here. But certainly, some of that hot air is going to enter this area. So, isn't that going to be heating up the brakes? Well, there's a duct here at the bottom to bring in cool fresh air, and then there's deflector plates on the suspension to redirect that air towards the brake rotors to cool them. Then, on the rear suspension, you can also see this arrow plate right here, which is mounted to the lower control arm, presumably to help reduce drag.
This is a quick bonus clip. So, I posted a photo of this car on the internet on the social medias, and I got a lot of uh feedback about it not being safe. So, we're gonna discuss very quickly about safety. Someone in the comments even referred to me as a "quote engineer," meaning like, not a real engineer, which they didn't realize engineers don't have feelings. So, no feelings were hurt in that exchange. But let's talk about what's going on right here. So, what is holding all of the weight of the right side of this vehicle? Well, nearly the entire weight of this vehicle is just on this floor jack. And you're wondering, wait a minute, there's a scissor jack right here? Yes, but it's redundant. If I were to remove that, the car would not fall down. Over here, that floor jack is holding it up. This scissor jack, I'm just giving it maybe like one more inch on this side. But if I were to take it out, the backside would just come down about an inch. It wouldn't destroy the brakes. And then, well, what if this floor jack fails? Well, there's a jack stand underneath it that's going to catch it. So, if the hydraulics of this floor jack were to fail, this jack stand right here would catch it.
So, what has to happen in order for this Porsche to ruin its brakes? Well, first, the floor jack has to fail. Then, the jack stand underneath it has to fail. And this scissor jack over here has to fail. So, if all three jacks fail, then it will hit the ground. But as long as any one of them works, it will remain elevated. So, I'm not super concerned about it. I'm not going to get underneath the car, but certainly for filming the brakes, I thought it was perfectly sufficient. Some of the comments disagreed. I'm not doing any work underneath the car. I'm not worried about it.
Thank you all so much for watching. If you have any questions or comments, of course, feel free to leave those below.