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I’ve stolen with pride from the GiroDisc website, and detailed below is the rationale for the improved performance expected by upgrading.

I’m hoping that one of the drivers that have made the move to GiroDiscs might be able to give a first hand review of what performance improvements they’ve noticed in making the change.

Source – Technical Section of the GiroDisc website

Girodisc Rotor Construction
The primary purpose of the Girodisc system is to reduce unsprung and overall vehicle weight. The secondary purpose is to increase the ventilation and cooling capacity of the brake disc while retaining it’s original dimensions. This is accomplished by using two-piece disc construction. The central “hat” section of the disc is made from 6061-T6 aircraft specification aluminum.

The disc is made from cast iron, to the same specification and material as used by professional racing organizations. It is 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 high strength alloy steel drive pins, manufactured by Girodisc to our own specifications and cadmium plated for a long lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. The pins are secured by grade 12 cap screws with hardened washers. In order to keep the rotors from making noise when cold, the pins are mounted with anti-noise spring clips on the rotor side which allow the rotor to grow with heat expansion but eliminate the rattle and noise associated with floating rotors. This float also allows the rotor to self center between the pads.

Important Questions Answered
Q: What is required to install the Girodisc system?
A: The Girodisc system is a direct replacement for the OE disc.
No modifications are necessary. The disc will bolt directly to the car and work with OE calipers and pads perfectly. Once the Girodisc system is in place, simply replace the cast iron rotor when needed. Some discs are larger in diameter and come with caliper spacers. If longer bolts are required, they are also supplied.

Q: How does reducing weight of the braking system benefit the vehicle?
A: The Girodisc will generally weigh between 4 – 8 lbs less than the oe disc it will replace. This is due to the heavy cast iron hat section being replaced with lightweight, high strength aluminum. The mass of any vehicle requires energy to accelerate or decelerate. Reducing the vehicle mass improves acceleration, and requires less energy to be dissipated during deceleration. Rotating mass requires additional energy in order to increase or decrease its speed of rotation. Decreasing the mass of the disc has a great benefit due to reduction in rotational inertia. This will allow more of the braking force to be available to decelerate the vehicle, not the disc.
Additionally, the mass of the brake system is also unsprung mass. Reducing the unsprung mass has the additional benefit of improved suspension performance, resulting in enhanced ride and handling. Rotating masses require additional energy to vary the plane on which they turn. The lighter the disc, the quicker the response of the vehicle steering due to the reduction in gyroscopic effect/rotational inertia of the disc. As an example, compare the weight of the Ferrari 360 OE disc at 18.2 lbs, and the Girodisc at 14 lbs. The Girodisc is 4.2 lbs lighter per disc. Replacing all four discs will save 16.8 lbs of rotating, unsprung mass.

Q: Why slotted discs?
A: The edges of the slots continuously clean and refresh the pad surface. This will allow the pads to have a maximized friction surface always available. Additionally, they prevent containments from collecting between the pad and disc interface.
The disc is lightened, decreasing its rotational inertia.
Slots prevent the formation of a water film on the disc in wet weather, maintaining the best brake response.

Project Mu pads have been produced in Japan since 1988 and have earnt a great reputation for precision engineering, excellent durability and delivering much more responsive braking. In Australia, Project Mu pads are used as the Control Brake Pad for the Australian V8 Supercar Championship Series and often used in the Bathurst 12-hour race.

With a range of size and specification options, there is a Project Mu pad to fit your Porsche and track day needs. Depending on the Project Mu pad that is right for your requirements, costs can vary from $400 – $900 for a set of Pads. Stuart our Cheif Technician would recommend that where possible you run Project Mu pads on both the front and rear. However, if budget doesn’t allow investing in both fronts and rears, moving to race brake pads just in the front is still worthwhile and should improve your on track performance.

In conjunction with moving to a race brake pad, we would also recommend the use of a high temperature race brake fluid to avoid the fluid overheating. At NINEAUTO we recommend using Castrol React SRF Brake Fluid for club and track days. This product has a very high boiling point of over 300°C which makes it ideal for use under more arduous braking conditions. For more information on race brake fluid, click on this link which will take you to a previous post, “How often should I change my brake fluid?”