If you are asking if 4 pot calipers will greatly reduce your stopping distance, the quick and simple answer is no, they will not. They do greatly improve overall braking performance, but they will not drastically reduce your stopping distance. If you don’t think your car stops soon enough, buy new tires. The calipers are, in fact, the only part of your car that ever touches the ground. The reasons for this are quite simple and based in physics.
How a Car Stops
According to the Standard Kinetic Friction Equation, it takes more energy to begin an object’s motion than it does to sustain it. So how does this apply to stopping a car? Well, the reverse of this law states that a tire in contact with the road will absorb more kinetic energy (e.g. momentum) just before it slides. Assuming the coefficient of friction is the same, (same tire, same road,) a braking system that applies more force to your rotors will bring about this threshold of sliding only milliseconds sooner. This will result in your ABS kicking in sooner to try and maintain this threshold. Now, if the tire contact patch is greater, and the rubber stickier, this point of force at which this threshold occurs changes greatly–making your car stop sooner.
4 Pot Calipers in Relation to ABS
In many instances, (especially in cars equipped with ABS,) 4 pot calipers can only elongate your stopping distance, even when correctly biased and tuned. This is because the ABS system activates sooner. Even the most modern ABS systems overcompensate. Meaning it releases pressure from the brake lines, allowing the wheels to move, and then reapplies said pressure, making them lock up again. The goal of the ABS is not just to keep the tires from sliding, but also to keep them right on the threshold of sliding, where energy absorption (again, momentum) is greatest. Even the most modern ABS systems cannot do this completely just yet. So we are stuck with a “lock, roll, lock, roll” pattern that brings us to a stop as fast as possible.
4-Piston Opposing CalipersSo what can 4-piston opposing calipers do for your ride, besides looking awesome? The number one performance increase occurs not when slamming on the brakes the first time (as previously discussed in the physics lecture) but, the second, third and tenth time. 4 pot calipers will react with much less brake fade than single or dual piston sliding calipers. It’s because with larger calipers and rotors, heat dissipation is greater. This can be magnified with the use of sport brake pads and larger rotors of different composites. Having larger calipers with opposing pistons also means that the braking force will be increased with less pedal movement. A car equipped with opposing piston calipers and larger rotors will have a harder-feel brake pedal, and will emit more force on the wheels as a sliding caliper with less pedal movement. So in essence, will your car stop sooner with bigger 4-pot calipers up front? No. Will it stop more consistently after time, with less brake fade and a firmer, short throw brake pedal? If installed right, and tuned correctly, absolutely. And it still looks awesome.