GiroDisc Front Brake Rotor Rings – Porsche 991 Cup / GT4 Clubsport – Factory PFC Hats

Description

GiroDisc Front Brake Rotor Rings – Porsche 991 GT3 Cup & GT4 Clubsport

Upgrade the front brake rotors on your Porsche 991 GT3 Cup or GT4 Clubsport with GiroDisc D1-370 slotted replacement rings, designed to fit the original Porsche Motorsport / Performance Friction (PFC) rotor hats.

These 380 × 32mm front rotor rings provide a direct replacement for the factory PFC friction rings while retaining the original aluminum center hats and mounting hardware.

Unlike GiroDisc replacement rings designed for GiroDisc-specific hats, the D1-370 uses the factory-compatible tooth-drive mounting arrangement.

GiroDisc Part Number: D1-370
Rotor Size: 380mm × 32mm
Sold as a pair – left and right front rings
Factory Porsche/PFC hats required – not included

Direct Replacement for Factory Porsche/PFC Rings

GiroDisc developed the D1-370 specifically for Porsche Motorsport applications using the original PFC two-piece brake rotor system.

These rings directly replace:

• PFC 380.32.0054.451 – Left Front
• PFC 380.32.0054.461 – Right Front

The replacement rings use the same tooth-drive mounting configuration as the factory components, allowing installation on the existing Porsche/PFC hats without purchasing a complete new rotor assembly.

Upgraded 72-Vane Cooling Design

One of the most significant differences between the GiroDisc D1-370 and the original PFC friction ring is the internal cooling-vane design.

GiroDisc D1-370: 72 cooling vanes
Original PFC rotor: 48 cooling vanes

The increased vane count is designed to improve rotor durability and longevity under the repeated high-temperature braking conditions encountered in competition.

For race teams running Porsche Cup or Clubsport cars, this provides an alternative to the original PFC replacement rings while retaining the existing rotor hardware.

Retain Your Factory Rotor Hats

The D1-370 is designed for customers who already have the factory Porsche/PFC two-piece rotor assemblies.

Instead of replacing the complete rotor assembly, remove the worn friction rings and install the GiroDisc replacements onto your serviceable factory hats.

This offers a practical way to upgrade the friction rings without purchasing new aluminum center hats.

Porsche GT3 Cup & GT4 Clubsport Applications

GiroDisc specifies these rings for:

• Porsche 991 GT3 Cup
• Porsche 981 Cayman GT4 Clubsport
• Porsche 718 Cayman GT4 Clubsport

Fitment requires the appropriate factory Porsche/PFC front rotor hats and tooth-drive hardware.

Important – Factory Hats vs. GiroDisc Hats

GiroDisc offers two different front replacement-ring designs for these applications.

D1-370 – Factory Porsche/PFC Hats

Designed to replace the original PFC front friction rings while reusing the factory Porsche/PFC hats.

D1-238 – GiroDisc Hats

Designed for customers who already have complete GiroDisc rotor assemblies with GiroDisc-specific aluminum hats.

These two replacement-ring designs are not interchangeable.

If your car has factory Porsche/PFC rotor hats, select D1-370.

If your car has GiroDisc rotor hats, select D1-238 instead.

Specifications

• Manufacturer: GiroDisc
• Part Number: D1-370
• Application: Porsche 991 GT3 Cup / GT4 Clubsport
• Axle: Front
• Diameter: 380mm
• Thickness: 32mm
• Minimum Thickness: 30mm
• Friction Surface: Slotted
• Cooling Vanes: 72
• Original PFC Cooling Vanes: 48
• Mounting: Factory-compatible tooth-drive system
• Required Hats: Factory Porsche/PFC
• Quantity: Pair
• Hardware: Not included

Features

• Direct replacement for factory Porsche/PFC front friction rings
• Fits Porsche 991 GT3 Cup and GT4 Clubsport applications
• 380 × 32mm
• 72-vane cooling design
• Slotted racing friction surface
• Reuses serviceable factory Porsche/PFC aluminum hats
• Compatible with original tooth-drive mounting hardware
• No need to purchase complete GiroDisc rotor assemblies
• Designed for demanding track and competition use
• Sold as a left and right pair

Important Installation Note

These rings are designed for factory Porsche/PFC rotor hats, not GiroDisc hats.

Inspect the existing hats and retaining hardware for wear or damage before reuse. Follow the applicable rotor assembly and inspection procedures.

If you are unsure which rotor hats are installed on your car, contact Demon Speed before ordering.