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SKU: D2-370
GiroDisc Slotted Rear Rotor Rings for Porsche 991 GT3 Cup/GT4 Clubsport
Maximize the braking performance of your Porsche 991 GT3 Cup or GT4 Clubsport with the GiroDisc Slotted Rear Rotor Rings, the industry’s leading choice for high-performance braking. Engineered for race enthusiasts and professional teams, these replacement rotor rings deliver superior stopping power, exceptional heat dissipation, and unmatched durability, outperforming OEM rotors and competitors like PFC, AP Racing, and StopTech. Crafted by GiroDisc in their Bellingham, WA facility using U.S.-sourced materials, these slotted rear rotor rings are the best choice for track-focused Porsche owners seeking precision, reliability, and cost-effective maintenance.
Why Choose GiroDisc Slotted Rear Rotor Rings?
The GiroDisc D2-370 Slotted Rear Rotor Rings are made from proprietary high-carbon cast iron, poured in the USA, and feature a racing-derived curved vane design with 72 vanes that act as a centrifugal pump to force cooling air through the disc. This advanced design ensures superior heat management, reducing fade and maintaining consistent performance during intense track sessions. The precision-machined slots enhance bite, clear brake pad debris, and improve braking efficiency, delivering a 15-20% performance boost over OEM rotors. Compatible with PFC and Porsche OEM hats, these rings offer a direct-fit, cost-effective solution for maintaining your GiroDisc 2-piece rotor system, making them ideal for endurance racing and high-performance track days.
What’s Included in Your Purchase?
- GiroDisc Slotted Rear Rotor Rings (Pair): High-carbon cast iron rings (380mm x 30mm) with precision-machined slots for enhanced braking and heat dissipation.
- Replacement Hardware: Includes 10 high-strength alloy steel drive pins (cadmium-plated for corrosion resistance), class 12.9 cap screws with hardened washers, and anti-noise spring washers to eliminate cold rattle.
- Installation Instructions: Detailed guide for re-assembly, available via GiroDisc’s website or included packaging. Optional re-assembly service available through select retailers (e.g., Apex Performance) for a nominal shipping fee.
- Part Number: D2-370
- Warranty: 12-month limited warranty covering defects in materials or workmanship (excludes labor, wear from racing, or consequential damages; void for improper installation or non-GiroDisc hat use).
Vehicle Fitment
The GiroDisc Slotted Rear Rotor Rings (SKU: D2-370) are designed as replacement rings for GiroDisc 2-piece rotor assemblies (e.g., A2-238) or PFC/Porsche OEM hats in the following vehicles:
- Porsche 991 GT3 Cup (2012-2019) – 2.0L Turbo (M97/74, 4.0L MA1.75)
- Porsche 981/982 (718) Cayman GT4 Clubsport (2013-2022) – 3.8L/4.0L (MA1.76, MDG.GE)
Important Fitment Note: These rotor rings are compatible only with PFC or Porsche OEM hats and GiroDisc 2-piece rotor assemblies (380mm x 30mm) using OEM race ZR68 calipers. Not compatible with PCCB (ceramic) brakes.
Verify hat compatibility and rotor specifications with GiroDisc or your retailer before purchase.
Performance Advantages
- Superior Braking Performance: Slotted design and 72 curved vanes enhance bite and heat dissipation, reducing fade and delivering 15-20% better stopping power than OEM rotors.
- Lightweight Construction: High-carbon cast iron rings reduce unsprung weight (approx. 19.8 lbs per rotor vs. 26.6 lbs OEM), improving acceleration and suspension response.
- Track-Proven Cooling: Curved vane design acts as a centrifugal pump, forcing cooling air through the rotor for consistent performance under extreme track conditions.
- Quiet Operation: Anti-noise spring washers eliminate cold rattle while allowing thermal expansion, ensuring street-friendly performance.
- Cost-Effective Maintenance: Reusable PFC/Porsche hats with replaceable rotor rings reduce long-term costs compared to full rotor replacements.
- Outperforms Competitors: Surpasses PFC V3, AP Racing, and StopTech rotors in cooling efficiency, durability, and ease of maintenance, making it the top choice for Porsche race teams.
Technical Specifications
- Material: Proprietary high-carbon cast iron (rotor rings), cadmium-plated high-strength alloy steel (drive pins)
- Dimensions: 380mm diameter x 30mm thickness
- Vane Design: 72 curved vanes for centrifugal cooling
- Slot Pattern: Precision-machined slots for enhanced bite and debris clearance
- Weight: Approximately 19.8 lbs per rotor (with compatible hat)
- Position: Rear axle
- Compatibility: Designed for PFC/Porsche OEM hats and GiroDisc 2-piece assemblies with OEM race ZR68 calipers
Important Notes
CARB Compliance: This product is not CARB legal and is not for sale or use in California for on-road vehicles (intended for off-road/competition use only).
Proposition 65 Warning: This product may contain chemicals known to the State of California to cause cancer or reproductive harm (www.P65Warnings.ca.gov) (www.P65Warnings.ca.gov).
Installation Warning: Use only with compatible PFC or Porsche OEM hats. Improper installation or use with non-compatible hats voids the warranty. Professional installation by certified mechanics is recommended, with regular track inspections required.
Warranty Limitations: Warranty is void for improper installation, racing beyond recommended limits, or use with non-GiroDisc hats. No warranty is offered for wear from track use or vibration due to improper setup.
Why the GiroDisc D2-370 is the Best Choice
The GiroDisc Slotted Rear Rotor Rings (SKU: D2-370) are the ultimate upgrade for Porsche 991 GT3 Cup and GT4 Clubsport owners seeking track-ready braking performance. With lightweight construction, superior cooling, and a slotted design, these rings deliver unmatched stopping power and durability, making them ideal for endurance racing and high-performance track days. Unlike competitors, GiroDisc’s U.S.-made, high-carbon cast iron rings and precision engineering ensure reliability and cost-effective maintenance, backed by over 20 years of racing innovation. Whether competing in Porsche Motorsport events or pushing your Clubsport to its limits, the D2-370 provides confidence-inspiring braking performance.
Order the GiroDisc Slotted Rear Rotor Rings (SKU: D2-370) today and experience unrivaled braking precision for your Porsche 991 GT3 Cup or GT4 Clubsport!
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