(ambient music) - For your car to operate the
way it's all mighty engineer intended it to. Its individual systems got
to be in the Goldilocks zone. Not too hot, not too cold. That goes for the engine,
the tires, even the driver. But one component that often
gets unnoticed are your brakes. Too cold, you get this,
too hot, you get this. So today, we're gonna
figure out why temperature is so important for your brakes. And to do that, we're taking a little field
trip to Wilwood engineering, to see how engineers
manipulate brake components to maximize their stopping power. You can manipulate brakes,
but you can't manipulate me. I'm unmanipulatable. - [Eddie] Glad you decided to
grow out that mustache Jerry. - Thank you, Eddie. That compliment gave me the
confidence to grow it out. Let's go. (upbeat music) Thanks to Kove for
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a limited time site-wide. Now let's boom, back to the show. I'm gonna take this here,
we don't need this anymore. This is how I carry
products out of the office. Oh, what do you got in your jacket? Nothing. Heat is the enemy of braking. Even though most brakes don't work great when they're extremely cold, brakes have no trouble
making heat and a hard time getting rid of it. When brakes get overheated, they don't stop well and
they can fail completely. That's more of a problem on
high performance and racing cars than a typical road car, but almost all cars use braking systems that operate the same way. To understand why
temperature matters so much. We first need to see how brakes work and they're not that complicated. For a typical braking setup. There are three main parts at each wheel. There's the disc, the
caliper and the pads. The disc or rotor as people call it is attached to the hub or axle and rotates along with the wheel. As it rotates, the disc passes
through a stationary caliper that holds the pads. When you step on the brake pedal, this increases hydraulic
pressure in the caliper pushing a piston into the
backside of the brake pad, which presses it against
the face of the disc. Manufacturers of road cars,
especially electric cars have recently introduced
electronic braking system. We did a whole B2B about those. So check that out over here if you want to understand the differences, but those still rely on
disc calipers and pads and despite their name, they'll
still use hydraulic pressure to create braking force. So, the heat problem applies
to those systems as well. The biggest difference
though is in the pedal because in an ordinary
hydraulic braking system, the resistance you feel with your foot is actually the pressure
in the hydraulic fluid. In an electronic system pedal feel is simulated
with a separate hydraulic or electrical system. But for today, we're gonna
stick with the juicy stuff because that's what you'll
find on most performance cars and at the racetrack. The fluid that takes
the paint off your car if you ever spill it on
there, been there brother. How your brakes work is pretty simple friction between the disc
and pads slows the wheel. And that friction is
produced by an increase in hydraulic pressure. But the two physical principles
that make brakes work friction and pressure, both create heat and heat is
what makes brakes stop working. Friction is just the force opposing motion between two surfaces and your brakes work by using frictional force to convert kinetic
energy into heat energy. With greater friction, more kinetic energy can be converted into heat, but you already understand this. It's why we rub our hands
together when we're cold. When a brake pad and a disc
really love each other, they make friction baby. (Jeremiah groans) The amount of kinetic energy
is based on the speed at which the two surfaces are moving
relative to each other. So the faster you move your hands, or the faster the brake disc is rotating the more kinetic energy it has. Not a lot of kinetic energy. A lot of kinetic energy. The amount of friction is
determined by the materials the two surfaces are made of. Any two materials have a
specific coefficient of friction. A number of usually represented
by the Greek letter mu. Mu is like u, but with a little tail, it's a u with a droopy neck. That's why brake pads
are sometime described in terms of their mu factor or mu level. The higher that number is, the
more friction they produce. But the total amount of
friction between two surfaces also depends on how much force
is pressing them together. In physics, that's Amonton's first law, the force of friction
is directly proportional to the applied load. So if you rub your hands together gently, there's not much friction and
they don't produce much heat, but if you really put some muscle into it, you can feel the heat in no time. The muscle in your brakes depend
on the hydraulic pressure. And you already know about
the direct relationship between pressure and heat. It's how a pressure cooker
works or a diesel engine, or even why a can of soda
left in a hot car can explode. As temperature increases, so does pressure and as pressure increases
so does temperature. It's why I get hot when I'm forced to release these episodes. (tense music) For a hydraulic system like brakes, which uses pressure to generate force. Every time you step on the pedal
and increase that pressure, it also increases the
temperature of your brake fluid. Stopping an object completely
requires enough friction to turn all of its
kinetic energy into heat. And in the case of a car,
that can mean a lot of heat. Kinetic energy is 1/2 mv squared. It's directly proportional to mass. So the heavier a moving car
is, the more energy it has, but kinetic energy also
increases as a square of speed. So a car moving 40 miles per hour has four times the
kinetic energy as it does when it's going 20 miles an hour. At 60 miles an hour, the same car has nine times
as much kinetic energy as it does at 20 and so on and so forth. All that kinetic energy being
turned into heat by the brakes is absorbed in the discs, pads, calipers and even hydraulic fluid. In a road car under normal driving that heat dissipates into the air. And you're unlikely to
notice any problems, but in performance applications that require repeated hard
braking, heat is a major concern. Excessive heat can work discs as the metal softens and deforms reducing the contact
surface with the pads. A pads mu factor also
changes with temperature. And at a certain point, they
won't produce enough friction to stop the car. Overheating the brake pads
can crack the material or cause it to glaze, meaning it turns smooth and glassy no longer able to produce enough friction, even once it's cooled. Heat can damage or rupture the
rubber seals in the caliper causing leaks that reduce
hydraulic pressure. And heat can boil the brake
fluid, turning it into a gas. So we understand that heat
is the enemy of brakes. So to find out how engineers
manage brake temperatures, we went to Wilwood engineering
where one of the major tasks when designing high performance brakes is getting rid of all of that heat. (upbeat music) So I'm here at Wilwood engineering
in Camarillo, California. They've got production,
they've got manufacturing. They've got it all. We're gonna walk around
and I'm gonna ask questions and figure out how these guys engineer better braking systems. Let's go, come on, come
on, Grant, let's go. I hear you're the man who's gonna give me a show of this place. - What's up man? How are you? - I'm doing well, thanks. - Good to have you here man. - This is Mike. Mike, why don't you tell
us a little bit about what you got going on here. - What we've got going on is this is where all of the R and D is done. We bring cars in, we test fit stuff. We design new brake systems. And then from here, we're gonna walk you through the shop kind of show you like the
progression of how stuff's made, but primarily calipers 'cause that's our primary stuff. - Okay, cool. - Cool?
- Yeah, let's do it. - So, primarily, caliper manufacturing, but like that caliper is our Dynalite. You've probably heard of that caliper. - Yes, sir. - So that one machine with one operator will do 250 inboard and
outboards in an eight hour shift - Oh thanks. - And very few failure rate. This is like the most
common caliper that we sell on a lot of our street applications, but also some race applications. - Okay, all right, cool. - [Mike] So over here,
there's one last thing that I think you'll kind of trip out on. So, this is like where we
used to get all of our dyno information and we're
talking from 35 years ago. - Okay, the OG set up. - This is super OG. In fact, when I started here,
it was still running on dos. - [Jeremiah] Oh nice. - [Mike] But there's no reason now for us to change any of this. - [Jeremiah] It works. - Well, we bad brake pads now with it. So we're not extracting
any data from it anymore. Basically what we're doing is pre-bedding for race applications,
brake pads, and rotors, and really even do it
together for a race team. - So can you explain what
betting and brakes means? - So, the betting procedure
is super important when you're talking about
high coefficient of friction, high temperature applications, what happens is it's kind of
tough to take your race car and drive it up and down the street here and even get it hot enough to get all of the saturation in the system so that the binder that's
inside the brake pad gets onto the face of the rotor. - [Jeremiah] Okay. - [Mike] We don't want
just the face of the rotor or the face of the
brake pads to be 'hard'. - Right. - We want all of the system to get hard. - The entire rotor, right
or just the entire system. - 7175 are the forgings
that you saw out there. - Yeah. So before, when we were in the diner, you were talking about
saturation temperature and how all the individual
components, when they get up, they need to get up to temp
to perform optimally, right? - Correct. - What happens when you
pass that threshold? What happens? - That's when you start experiencing fade. - Okay. - So when you start to experience fade, one of the first things
that'll start to happen is maybe you don't have
the right brake fluid. You might have like a
DOT three brake fluid, and you really need to
step up to a DOT four something that has a higher boiling point. So the next thing is,
rotors are very important. This is one of our premium
spec, 37 race rotors, and it's not only directional
vein, it's also staggered vein What we learned from testing was if we were to close this stagger, there wasn't enough air getting flown. So now we've got way more capacity. We can cool off the rotor a
lot better, super important. - Okay, so here we have two
different types of brake pads and you said two different ways
that they were manufactured. Okay, so how was this made right here? - So, this backing plate
you can see is flush. - Right.
- Right. There's no holes in it,
that one's got holes. - Right. - So anything that we're
gonna do for racing, we don't want holes because that's gonna add
deflection in the pad. All right. The other thing about this
pad is it was made with NRS. So feel that.
- Gotcha. So that's what's getting
that to grip onto this piece of metal right here, right? - I hate to say the word,
but it's almost like Velcro, right?
- [Jeremiah] Okay, yeah. - [Mike] So when we manufacture this particular type of setup under super high heat and pressure, we press the material
onto this backing plate. - You know, obviously the
material pad composition is a huge influence or the factor when it comes to the coefficient
of friction of the pad temperature range as well. Is there a specific compound in particular that higher temperature pads have in it that allow for that ability
to take that much heat? - So all the pads that
we're talking about today are gonna be what we sell,
which are semi-metallic. - Semi-metallic, okay. - So, here's the thing
that I don't even know is the ratios for
different pad formulations. Some might have more nickel,
more copper, more beryllium different things that cause the pad to do what you're asking it to do. - Right, so different secret formulations of metals in this pad
determine the temperature range and the coefficient of friction. - Absolutely.
- Okay. - And in a lot of cases,
like I joke around, but. - [Announcer] Sergio 709, Sergio, 87609. - Sergio, 07. All right, I was hoping you
were gonna be able to tell me the secret formula. - No.
- It's cool, you don't have to - No, I'm not going to. So, all of our engineering staff is here in building number one. So we do all of our dyno testing when we've got a new project, when we've got friction
materials that we want to try or test.
- Right. - So, this is our link. Now this is pretty much state-of-the-art dynamometer for doing brake systems. - [Jeremiah] Okay. - [Mike] It's all electric. It has the capacity to be
able to give you the inertia of 30,000 pounds. - [Jeremiah] Oh wow. So you can do calipers, pads, rotors all in this one machine. - Yes. - Okay, great. We're gonna get to run it. - Yeah. - I get to hit the big button over there. - That's the turn off button. You don't want to hit that. - You don't know that. (upbeat music) A brake dynamometer or
dynamometer or brake dyno is often used to measure
the amount of power a car is transmitting to its axle. But it can also be used
to measure the force of a braking system. Advanced brake dynos
like the one at Wilwood could even be programmed
to run simulations of specific racetracks to
determine the conditions the brakes will face over
the course of a race, helping engineers choose
the best braking setup. Wilwood engineering has
been designing and building performance brake components for 45 years. They make everything from
high performance pads, big brake kits for road cars to fully custom setups for racing. I got to set of Wilwood brakes
on the old catfish Camaro They get me out of the jam
when I'm going too fast. But I drive with the speed limit. Most brake discs are made from iron. These are cheap and effective,
but they're also heavy. So some race cars will use
steel, which can be made thinner, lighter and has greater
thermal connectivity. Meaning they dissipate heat faster, but steel wears quicker and
is more prone to warping than iron. Aluminum dissipates
heat better than steel, but it also has a lower melting point. So it's only used for
lightweight applications like motorcycles or as the hub component of a two piece rotor with a disc made of iron,
steel or carbon ceramic. That's what's used on
some of the most expensive performance cars in the world, like the Bugatti Chiron and Rimac Nevera. Because the two-piece
carbon ceramic brake disc can be made large,
lightweight and heat resistant at a cost of course. Carbon brakes, they can
be as much as 21 grand. If you want the option then
for your Porsche 911 turbo, for example, that's like a car. You buy a whole car for that.
Keeping a brake this cool isn't just about the material size and construction matter too. Big brake kits like the
ones designed by Wilwood use larger discs, larger disc
means heat is spread out more and their greater surface
area means more disc is exposed to cool air. All of which helps dissipate heat. Engineers will also
design discs with vents wave patterns, slots,
grooves, dimples, and holes to increase surface
area and create passages for hot gases to be
channeled away from the disc. Pads have a huge impact
on braking performance. Like tires, each pad
has a unique compound. That's the mixture of
materials it's composed of and just like tires, the compound determines the amount of grip
or friction it can produce. And the temperature
range at which it works. Like tires, brake pads don't
work well if they're too cold or too hot. Pads fall into three general types. You've got organic, ceramic and metallic. Organic pads are made from
materials like glass, rubber and Kevlar bonded together with resin. A lot of road cars come with organic pads because they're quiet, but they also don't
create a lot of friction and wear quickly under hard braking. So they are a poor choice
for performance application. Ceramic pads are made from ceramic fibers. They're incredibly durable
and good at dissipating heat, but like carbon ceramic brakes, they're incredibly expensive. So they're the least
common of the three types. Most performance pads are metallic made from a combination of
metal shavings and resin. Metallic pads can include
copper, steel, graphite, brass, but the exact mixture of any specific pad is a closely guarded secret like Kentucky fried chicken's recipe. By varying the materials
in the pad compound. Engineers can dial in pads to work at just the right temperature
for different application and to avoid brake fade. That's when the pads get too hot to work and the amount of friction
it produces drops off. In the quest for speed,
many enthusiasts add power, and they don't spend much
time thinking about brakes. But when engineers think about speed, brakes are an essential
part of that equation and maintaining the right
brake temperature is vital for hard stops and fast laps. On a racetrack, speed on the streets. It doesn't do you any good if you can't get rid of
it before the next turn. - Ho-ho-ho.
- Happy holidays Donut fans. - We want to personally let y'all know it's your last chance to order donut swag before the holidays. - Get your orders in before December 10th. - And never forget
'cause we're Island boys. ♪ I'm a donut boy. I'm gonna
keep it, I'm a donut boy ♪ ♪ I'm gonna keep it, I'm a donut
boy, I be eating it all up. ♪ ♪ It's so good, I be eating them crumbs. ♪ ♪ I'm like, go, I go so dumb. ♪ ♪ I love donuts. ♪ ♪ Shout out to Donut media fans. ♪ - I want to thank everybody
at Wilwood engineering who helped out with this episode. Those guys are great over there. If you want more information about them, we'll put a link down in
the description below. You want to see more
videos about the catfish. Watch this video over here. Man, I think it's looking sick, isn't it? Ooh, this gets me all hot inside. Follow us here on
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