If you’re heading to your first SCCA® Time Trials event, I have one quick word of setup advice for you: brakes. Most of the time, we don’t have to think much about the brakes on our cars. If we’re driving to the grocery store to buy more Cap’n Crunch Berries and come across a red light, we simply hit the “whoa pedal” and the car stops. On the street, brakes generally work every time. But on a road course under the pressure of a Time Trials or Track Day (or Track Night), this is where things get heated – literally.
On the track, you’ll be going much faster than you drive at an autocross or a RallyCross, and certainly faster than when you buy those Crunch Berries. And since racetracks have a series of turns (some tighter than others), you’ll be required to slow that speed to make it to the next corner. All of that slowing means your car’s brakes are working harder than ever.
Allow me to lay some science on you. The speed you’re traveling and the weight of your car have something physicists refer to as kinetic energy (an object that is moving), and slowing down kinetic energy takes work. The brakes on your car do the work needed to slow the car down, and that kinetic energy is transferred into heat. The heat has to be stored somewhere, and that “somewhere” is your brake components. The more kinetic energy being slowed equals more heat. So, as you lap the track, accelerating down the straights and using the brakes before every corner, your brakes are doing a lot of work and creating lots and lots (and lots) of heat.
“I get it, brakes get hot, I knew that,” you may say. Great point, and you’re not wrong. What many people who’ve not done a track event don’t always realize is how much brake heat is created at the track, and how that heat can negatively affect a stock braking system. Unfortunately, many drivers find out the hard way when their brake pedal becomes soft (or worse, sinks to the floor).
By and large, passenger vehicles that come from the factory are designed to give you immediate panic braking on a cold, wet morning. If a dog runs in front of your car and you hammer the brakes, the car will stop quickly. Stock vehicles do a great job of this. What they’re not designed to do – even most of the ones that are marketed to us as sports cars or performance vehicles – is slow multiple times from high speeds over and over again. Why not? It comes down to a multitude of things manufacturers consider when building a car. Some of it involves cost, some is avoiding brake pad squealing or excessive dust, some is brake pad choice for cold stops, and some is smaller brake components for more fuel efficiency. Rarely are a car’s brakes designed for track duty straight from the showroom floor.
Here's the good news: By making a few adjustments to your stock braking system, you’ll be able to go lap after lap, use the brakes over and over again, and have confidence as you come flying into the next corner.
Here are five things you can do.
1. Brake Fluid
The first thing I do to any car I’m taking to the track is replace the brake fluid.
Brakes are a hydraulic system. What that means is when you hit the brake pedal, you push fluid inside brake lines to the calipers at each wheel. The fluid squeezes pistons that push the brake pads on to the spinning brake rotors, which is what slows the car down. For the system to work, the fluid needs to not compress. “Why not use water? Water doesn’t compress?” Under the pressures we’re talking about, water doesn’t compress – in liquid form. But at 212 degrees F, water turns into gas, and your brakes get way hotter than 212 degrees. This is also why it's important not to have water or condensation in your brake lines: Gas compresses, and this is how a brake pedal can feel soft.
(Replacing brake fluid with something with a higher boiling point is key to success at the track. Photo courtesy Hawk Performance.)
Generally, stock brake fluid is made with a fluid called glycol ether, which is rated as a DOT 3 and has a minimum dry boiling point of 401 degrees. That’s great for trips to Costco, but brakes at the track can easily exceed 401 degrees and boil the fluid, which means the fluid turns to gas, which means the pedal goes to the floor … which means you soil your pants.
I replace my brake fluid with any brand that uses borate ester, rated at DOT 5.1, which has a dry boiling point of over 500 degrees (some fluids have ratings well over 600 degrees). What you use is up to you, but do not use DOT 5 fluid, which is silicone – that stuff doesn’t mix with DOT 3, 4, or 5.1 fluids.
Two quarts of high-performance brake fluid will set you back no more than $100. Replacing an entire car that hit a tire wall? That’s a little bit more than $100. This is an easy investment to make.
2. Brake Pads
The compound of the material of the brake pad makes a huge difference in how those brake pads react to heat. Stock pads are designed for a cold stop, low squealing, and low brake dust. What you want for repeated hard brake applications is a brake pad made with a carbon metallic material that has a much higher thermal dynamic threshold. The good news here is this is an easy upgrade. There are plenty of aftermarket companies that make high-performance brake pads that will easily fit directly into your OE brake calipers (quick reminder that Hawk Performance is the official brake partner of SCCA, and we love to support those who support the sport).
(Brake pad selection is key to a successful day at the track. Photo by Adam Brooks.)
All you have to do is swap out a different set of pads and then go hard into the next corner. But like anything in life there’s always a tradeoff. Brake pads with a very high thermal dynamic threshold don’t have very good cold stopping power, which is why you see road racers warm up their brakes before they take the green flag. Also, these extremely good pads for road courses tend to squeal like crazy and create tons of brake dust. This isn’t a problem on the racetrack, but can be annoying when driving on the street.
Some Time Trialers swap in sticky pads at the track and use their OEM pads for the street, while others find a brake pad that’s middle of the road. Talk to the experts at your favorite brake manufacturer – they know their stuff and have lots of compounds to choose from.
3. Brake Lines
We’ve already discussed how we don’t want any compression in our brake fluid. What we haven’t discussed is the actual materials that are used for these hydraulic lines. Because cars have suspension and steering that articulates, brake lines cannot be made completely of solid metal piping, so there’s a small portion of the brake line between the chassis and the brake caliper that’s made of rubber.
When you push on your brake pedal hard, you can expand that rubber line ever so slightly, making your brake pedal feel a bit soft. By replacing the rubber lines with flexible metal ones, you take away that expansion in the line and have a more solid brake pedal feel.
Bonus: Even for the entry-level Sport category in SCCA Time Trials, brake lines can be upgraded.
4. Brake Bleeding
Brake fluid doesn’t circulate in the system. What that means is the fluid that’s inside your brake caliper is the same fluid that has been heated and cooled hundreds of times. Even if you have DOT 5.1 fluid already swapped into your brake system, very little of the fluid has seen continual extreme temperatures from hard braking at the track. You’ve probably seen teams bleed just a few inches of brake line after a long session on the track to replace the fluid in the caliper with some fresh, less exposed fluid. This is a great method for ensuring your braking system is optimal.
(Bleeding the brakes is a simple, but necessary, process.)
5. Brake Ducting
There’s been a lot of discussion here about brake heat, yet we’ve only covered what OEM parts can easily be swapped out for aftermarket ones to control that heat. What we haven’t discussed is other methods to cool the brakes.
Brake ducting is a fantastic way to help keep temperatures down by pushing cool air onto brake components. Brake ducting can be as simple as a piece of plastic attached to a swaybar that directs air onto a brake rotor, or more complex systems of ducting, high temperature hoses, and attachment points to dust shields to ensure the cool air is directed to the brake rotor or hub. The more air you can direct toward the brakes, the cooler your brakes will be, which means the longer you can stay on track.
(Brake ducting can be as simple as a piece of plastic that "encourages" air toward the brakes (above), or as robust as the setup used in the lead image for this story.)
Before signing up for your first SCCA track event – especially if you’re taking your daily driver – take a good look at your brake system and consider these five easy and inexpensive steps to ensure your safety and your car’s well-being. You’ll also improve performance and have a great weekend at the track!
(About the author: Rob Krider is a national champion racer, the author of the novel Cadet Blues, and is the host of the Stories and Cocktails podcast.)
Photos by Rob Krider (unless otherwise noted)
