Nissian Spec-V: Part 12: Modifying the Brake System
9/28/2006
Since the horsepower and tire upgrades, the demands placed on our braking system have gone up considerably. Although perfectly adequate for street use, the stock brakes were not designed for repeated high-speed use for extended periods.
We called upon the experts at Stoptech to cure our brake issues. Stoptech gave us a racing brake kit with ST40 4-piston calipers and 13-inch floating rotors. These brakes should slow us down from any anticipated speed with ease.
We chose Stoptech front brakes because they offer the proper piston size for the calipers to maintain correct hydraulic proportioning. Typically, aftermarket brake upgrades have far too much front brake bias and a mushy pedal due to the use of a large pistoned racing brake caliper. Fortunately, Stoptech does not have this issue because of the correct caliper piston sizing for each application, which maintains the brake balance near the stock balance.For the rear brakes, we used Fastbrakes slotted rear rotors with the stock calipers. Since the front brakes of a nos- heavy FWD car like the Spec-V do 80 percent of the work, the stock rear brakes would work fine with a simple rotor upgrade.
Although the Stoptech brakes are big, they are actually about 6 pounds lighter than the stock brakes due to the aluminum alloy construction.
For our front and rear rotors we chose slotted-over-drilled rotors. Slotted and drilled rotors help brake performance because they provide a place for vaporized brake material to escape under hard braking. This material acts like a lubricant and reduces the brakes effectiveness under hard use. We used slotted rotors because drilled rotors often crack under hard racing use.
For front brake pads, we chose Performance Friction’s 01 Compound. This brake pad compound has good bite even at very high temperatures. For the rear we used Carbotech XP10 Compound, we have found this to work exceptionally well on the rear brakes of FWD cars.To fine tune our front-to-rear brake bias, we installed a Tilton Brake proportioning valve from Bits n Pieces Motorsports. This valve allows us to decrease or increase the amount of rear braking power from inside the cabin instantly to compensate for fuel load or driver style.
Finally, we filled and bled our brake system with Motul RBF 600 brake fluid. Motul brake fluid has excellent boiling resistant properties at very high temperatures.
With the brakes installed, we check fitted our Volk TE37 wheels, sized 17x8 inches with a 38mm offset. As you can see here, the wheels easily cleared our brakes. These forged wheels are ultra-strong and light. With our suspension and brakes coming together, it will soon be time to focus on the engine.