Save Money and Upgrade Your Porsche 991.2 GT3 RS's Brakes for Reliable Track Performance with Girodisc Cast Iron Rotors

Performance Tuning

Oct 11

At Murtha Motorsports, we recently had the opportunity to work on a Porsche 991.2 GT3 RS equipped with PCCB (Porsche Ceramic Composite Brake) rotors. For our customer, who intends to use their car on the track, we installed a Girodisc Iron Cast brake conversion. While PCCB rotors are known for their excellent performance on the street, they may not withstand the high temperatures generated by repeated high-speed stops on the racetrack as well as iron cast rotors. The Girodisc Iron Cast rotors offer a durable and reliable option for track use, and can save our customer money compared to replacing their PCCB rotors.

Downsides to OEM Carbon Ceramic Discs

Oxidation at track temperatures
High disc surface temperatures-
Low thermal conductivity
Expensive and limited range of compatible brake pads
High replacement disc cost
Damage-prone
Greater sensitivity to burnishing/bedding-in

Girodisc Porsche 991 GT3, GT2RS PCCB Iron Rotor Conversion

The Girodisc system is a direct replacement for the OE disc. However, you must use the same pad shape on the 991 GT3 that came with the iron rotors from the factory. The annulus (pad swept height) of these pads is smaller than the large PCCB pads; this is done to keep the rotor weight at a reasonable level and allow far better pad selection. They would be unnecessarily heavy if we manufactured a rotor with the same annulus as the OEM PCCB rotors. The central hat section of our rotor is made from strictly U.S.-sourced 6061-T6 aircraft specification aluminum. The disc is made from our proprietary cast iron, poured in the USA, and machined from start to finish in-house at Girodisc. The rotor utilizes a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the disc. The rotor and hat have a floating mount system, which utilizes ten high-strength alloy steel drive pins manufactured by Girodisc in the USA to our specifications and cadmium plated for long-lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. Class 12.9 cap screws secure the pins with hardened washers. To keep the rotors from making noise when cold, the hooks are mounted with anti-noise spring washers on the rotor side, allowing the rotor to grow with heat expansion but eliminating the rattle and noise associated with floating rotors. This float also allows the rotor to self-center between the pads. Once the Girodisc system is in place, replace the cast iron rotor when needed.