AP Racing Radi-CAL Competition Rear Kit 380mm - Porsche 981, 718 GT4

The AP Racing by Essex Radi-CAL Competition Brake Kit is a rear brake upgrade for the Porsche 981 Cayman GT4 and the 718 Cayman GT4 and Spyder. It pairs AP Racing CP9449 Radi-CAL Pro5000R racing calipers with 380 x 32mm, 72-vane AP Racing J Hook discs on fully floating aluminum hats, built for track days and competition driving. Fits OEM 20 inch wheels without spacer.

Why upgrade

Saves 18 unsprung lbs. versus OEM iron brakes and weighs almost the same as the OEM PCCB system. Each caliper weighs 4.85 lb without pads, against 7.5 lb for the factory iron System caliper. Each two-piece disc weighs 19.1 lb, compared with 24 lb for the original 380mm disc. The caliper takes a 16.75mm thick pad for long life and heat tolerance. Pads change without removing the caliper. The OEM parking brake keeps working. The caliper takes pads from all major pad manufacturers. Every component is designed to resist the heat of extended track sessions. Pistons are sized to work seamlessly with the OEM master cylinder and ABS.

Caliper and disc construction

On the Porsche 981, 718 GT4, the CP9449 caliper mounts radially on a dedicated bracket at 152mm centers with a 44mm offset, with an M10x1.0 inlet thread. The anodized caliper finish resists wear and deterioration at high temperatures. Stainless steel caliper hardware gives a long service life even with frequent pad changes. There are no dust boots to burn up at track temperatures. Pads change with one bolt, with no caliper removal. The championship-winning 72-vane AP Racing J Hook discs are fully floating. The discs use anti-knockback, anti-rattle attachment hardware. The disc metallurgy is designed for the temperatures seen on track, for a long service life.

Features

• AP Racing CP9449 0-piston calipers
• 380 x 32mm, 72-vane J Hook discs on floating hats
• About 18 lb less unsprung weight
• 16.75mm thick brake pads
• Pistons sized for the OEM master cylinder and ABS

What's Included

• One pair AP Racing CP9449 Radi-CAL Pro5000R racing calipers
• One pair caliper mounting brackets and hardware
• One pair Spiegler Stainless Steel Brake Lines with abrasion resistant coating
• Detailed installation instructions

Brake pads are not included.

Specifications

Video

Fitment notes

This rear kit fits the vehicles in the table below, which we confirmed against two sources using US model years. Essex has confirmed clearance with Forgeline 18 x 10 inch +35, Forgeline GS1R 19x10.5 inch & 20x11.0 inch, Forgeline GA1R 19x10.5 inch & 20x11.0 inch, Forgeline VX1R 19x10.5 inch & 20x11.0 inch, Forgeline GT1-5 19x10.5 inch & 20x11.0 inch and HRE R101 20 inch. Check your wheel with the Essex wheel fitment template before ordering.

Fitment