In the quest for more horsepower, brakes are often the last items to be addressed - they’re dirty, hidden behind the wheels and don’t add any power; however, to safely increase a car’s performance, you must be able to harness all those extra ponies consistently and reliably. They may not make your ride faster in a straight line, but around a track, upgraded brakes will absolutely improve your lap times. Your car’s stock brakes are matched for stock power levels, just like the suspension, fuel system and engine internals. You can push them, but only so far. While full-on racing setups can be astronomically expensive, significant improvements can be made your car’s stock brakes for relatively little cost.
The first upgrade for stock brakes is also the cheapest and easiest to install. Replacing your stock brake pads with a more aggressive set will provide a noticeable improvement in braking performance. This increase in stopping power comes from alternate compounds in the pads; semi-metallic and ceramic are two of the most common pad types. In addition to their stopping capability, noise, wear, brake dust and environmental friendliness are other factors to consider when selecting new pads.
Semi-metallic pads utilize steel fibers which provide excellent strength and heat dissipation, but are noisy, generate more brake dust and are abrasive enough to significantly increase rotor wear. Ceramic pads are generally regarded as the best all-around choice for daily use and occasional ‘spirited’ driving, as they extend brake life and produce less dust and noise without sacrificing performance.
Repeated, high-speed stops generate extreme heat, which is why the brake pads used in racing applications are not suitable for everyday street driving – the pads will never get hot enough to provide their full stopping power.
Bigger is Better
The next step is to replace your rotors with the biggest ones that will fit the stock setup. Bigger rotors provide a larger contact patch for the pads and dissipate heat more effectively. Cross-drilled and slotted rotors may enhance aesthetic appeal and help evacuate the gasses that induce brake fade, but are more prone to cracking and should not be considered appropriate for high-speed track use when sold as OEM replacements. If you do plan to use drilled/slotted OEM replacement rotors on the track, be sure to carefully inspect them for cracks and signs of deterioration; also, expect them to be noisier than your stock discs.
Now that you’ve decided to replace your pads and rotors, the next step is to properly ‘bed-in’ the pads with the new rotors to maximize their performance. This process involves a gradual buildup of heat, which will produce a thin layer of transfer film from the pad onto the rotor surface to provide smoother, more consistent braking and minimize brake judder and noise.
If you are reusing your rotors but installing new pads, make sure the rotors have been resurfaced to remove any transfer film from the old pads. If you can feel a “lip” on the edge of your rotors, resurfacing or replacement is required. Since resurfacing removes mass from the rotor, it may become more prone to warping in the future; past a certain point, rotors cannot be resurfaced and must be replaced. Check the “Worn Rotor Minimum Thickness” value engraved on the edge of the disc for the exact limit.
Bedding-in procedures differ depending on manufacturer, but typically involve light to moderate braking, followed by a period of driving to allow the new components to cool off. The process is then repeated several times, usually followed by progressively heavier braking.
Another popular, effective upgrade for your stock brakes is to replace the factory hydraulic brake lines with a set of high-performance stainless steel lines. The stock, rubber lines can flex and expand under pressure and give the brake pedal a vague, “mushy” feel; rubber is also more prone to cracking and deterioration over time. Stainless lines will not expand or crack and provide a much firmer, positive pedal feel.
When replacing brake lines, it is imperative that you properly bleed the brakes to purge any water or air bubbles from the system - even the smallest bubbles can translate to a brake pedal that feels soft and imprecise.
Still Not Enough?
Once you’ve upgraded all of these components, you should see a noticeable improvement in your car’s braking, with more consistent stopping power. If your car is making significantly more power than stock, or if it will see regular track use, a more substantial upgrade may be in order.
Bigger calipers will increase the clamping force applied to the rotors and will drastically improve the stopping capabilities of your brake system. The hydraulic fluid compresses a piston or “pot” in the caliper to force the brake pad against the rotor. The vast majority of vehicles are equipped with single-piston or dual-piston calipers up front and a single-piston caliper in the rear. Most performance automobiles and brake upgrade kits employ a 4-piston caliper at minimum, while some use 6-piston or even 8-piston calipers for extreme stopping power.
Additionally, high-end setups will often use 2-piece rotors, where the outer ring of the rotor is a separate piece from the center hat, which is where the whole assembly bolts to the wheel hub. This configuration allows for the different metals used to expand and contract at different rates, reducing stress on the rotors and extending their life.