If you're thinking about upgrading your brakes, you'd better like choices. Do you want four pistons in your calipers? Or maybe six, or eight? Rotors with cross-drilled holes, slots, or both? Wanna go big with those rotors? Would that be solid or two-piece discs? And how do you take your pads? Organic? Semi-metallic? Mild or hot? With a side of ranch dressing?
For some, the choice is easy. All a show car really needs is the biggest, wildest looking brake kit that'll fit behind those tall, wide-open rollers. If, on the other hand, you're interested in improving actual brake performance more than aesthetic appearance, all those above choices, and more, pertain to you.
With that in mind, what follows is a description of what a brake upgrade can do for you and the roles that the brake system's various components play in improving stopping performance. As usual, we've talked to several experts in the field, and, as usual, they don't always agree. So weigh the information here, visit the Web sites, and above all, talk to the brake companies about your car and your specific driving needs. As you'll see, no single brake upgrade will work for every car in every driving condition.
When Do You Upgrade?
Given the current state of original-equipment brake technology-which, our experts agreed, is pretty damn good-a well-maintained stock brake system should work just fine in an unmodified car that's used for typical daily transportation.
In fact, Dan Barnes of StopTech surprised the heck out of us when he said, "If you have a properly-functioning, well-designed brake system already, the only thing you can do to improve single-stop braking distance is get better tires. Any force that accelerates, slows or stops the car can only be applied through the tire's contact patches. If your current brake system is using all four tires to stop the car as effectively as possible, no brake system change will result in a shorter stopping distance."
So if better brakes won't help you stop shorter, what will they do? Here's Chris Bernal, brake division manager for Stillen: "Let's say a guy goes to a track day once in a while, or he drives the canyons hard, going deep into corners-within the legal limits, of course. He's building heat in the brake system. Most vehicles as delivered from the factory have great brake systems to keep from hitting people in crosswalks, but not to deal with heat buildup. If you're feeling brake fade or a soft brake pedal, you need an upgrade."
Modified cars are prime candidates for upgraded brakes. "Anyone increasing horsepower to achieve higher vehicle speeds, or upgrading to wheels and tires with a bigger circumference or a larger traction footprint, should also be considering enhancements to the braking system," said Wilwood's Carl Bush. Added Dominic Chen of Endless USA, "As you increase horsepower it becomes more necessary to increase brake power. But you want to keep it proportional. Add 500 hp and you'll want a substantial increase in braking power. A 20 hp increase, on the other hand, won't need as much."
How Brakes Work
Notice some of the words that those comments had in common? "Fade" was one. "Heat" was another. To understand why, you should know a little about how brakes work.
Like a lot of what goes on in our cars, braking is all about transferring energy from one state to another. "Brakes convert the kinetic energy of your moving car into heat," explained Barnes. That heat is "temporarily stored in the brake components-mostly the pads and rotor-and then shed into the surrounding air. Some heat is transferred into the wheel, hub, caliper and other places rather than to the air directly, but it eventually all gets into the air."
Brake fade occurs when the heat generated by hard or repeated stops exceeds the brake components' optimal temperature range. "Fade can happen when the brake pad's friction material and rotor are too hot," explained Mark Valskis, Brembo North America's Chief Engineer. "Beyond that, assuming you have a pad upgrade but stock rotors, you might have problems with heat soaking into the calipers and boiling brake fluid. Either will result in dramatic reduction in brake performance."
Because heat is such a critical factor in braking, many of the components in a brake upgrade-from the pads and rotors to even the brake fluid-are designed to either dissipate heat or operate effectively at higher-than-normal temperatures. Yet thermal stability, and the resulting brake performance consistency even under harsh conditions, are just part of what you get from a good brake upgrade. You should also expect greater stopping power, the proper balance in braking force between your front and rear tires, better brake modulation and a firmer pedal. All of these traits combine to improve the brakes' overall "feel" and enhance your driving confidence, especially when braking late on your favorite canyon road or coming up to that nasty right-hand hairpin turn lap after lap after lap.
Two-Piece Rotors
A two-piece rotor is typically one in which the rotor disc (an example from Wilwood is shown here) is made of iron, while the rotor hat, which attaches to the wheel hub, is made of a lighter material, such as aluminum. This construction shaves weight off the rotor and helps protect the wheel hub from damage from excessive heat, since aluminum dissipates heat better than iron. | 
Replacement Rotors
Another entry-level brake upgrade is to swap a car's stock rotors for a set of same-size rotors with performance modifications, such as these drilled, slotted and zinc-washed DecelaRotors from Baer. |
Stock Swap
A big-brake kit might be overkill for a nearly stock car that's driven hard, but only on the street. Instead, stepping up to high-performance brake pads, fluid, and stainless-steel-braided brake lines, such as these in StopTech's Stage 1 kit, will improve a stock brake system's thermal stability and pedal feel, as well as giving the driver better brake bite. | |