The high performance brake systems of today are usually in a delicate balance - walking the fine line between being overpowered by some of the most potent powertrains, some of the grippiest tires, and some of the most demanding race tracks that the automotive world has ever seen - and saddling the vehicle with excess kilograms of unsprung mass with oversized brakes, forcing significant compromises in drivability with oversized tires and wheels. Brake system design for high performance vehicles has often relied on a very deep understanding of friction material performance (friction, wear, and compressibility) in race track conditions, with sufficient knowledge to enable this razor’s edge design. With significant restrictions in copper content of automotive brake linings becoming reality in California and Washington State in 2021, and a more or less complete phase-out of copper in linings occurring in 2024, one of the key ingredients of high performance linings - critical for heat transfer, high temperature tribofilms, and medium to high temperature friction - can no longer be used.
This paper looks at dynamometer-based performance data from a new generation of copper-free high performance brake linings, and makes comparisons where appropriate to a current copper-containing lining. Following brake system sizing methodologies (some of which have been described in literature previously, and some of which are new and generate improved correlation to race track operation), the brake system of a case study high performance vehicle is reviewed for the impact that the copper free linings has on it. Data are generated using analysis tools, with correlation to vehicle test results. It will be shown that meeting the demands of race track usage with copper-free lining materials is possible, but that it will affect brake system design in some cases.
