AP Racing Radi-CAL Competition Front Kit 394mm - Porsche 981, 718 GT4

The AP Racing by Essex Radi-CAL Competition Brake Kit is a front brake upgrade for the Porsche 981 Cayman GT4 and the 718 Cayman GT4 and Spyder. It pairs AP Racing CP9661 Radi-CAL Pro5000R racing calipers with 394 x 34mm, 84-vane AP Racing J Hook discs on fully floating aluminum hats, built for track days and competition driving. Clears OEM 20 inch wheels without a spacer.

Why upgrade

Saves 15 unsprung lbs. versus OEM iron brakes and weighs almost the same as the OEM PCCB system. Each caliper weighs 6.2 lb without pads, against 9.3 lb for the factory fixed bridge one-piece caliper. Each two-piece disc weighs 21.5 lb, compared with 24.2 lb for the original 380mm disc. The 18mm pad is thicker than the 16.6mm factory pad, so it lasts longer and absorbs more heat between changes. Pads change without removing the caliper. 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. It works with the OEM rear brakes or a matching AP Racing rear kit.

Caliper and disc construction

On the Porsche 981, 718 GT4, the CP9661 caliper mounts radially on a dedicated bracket at 180mm centers with a 42mm offset, with an M10x1.0 inlet thread. Ventilated, domed-back stainless steel pistons keep heat out of the brake fluid for a very firm pedal. Anti-knockback springs behind the caliper pistons limit pad knockback. 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. The championship-winning 84-vane AP Racing J Hook discs are fully floating. The discs use anti-knockback, anti-rattle attachment hardware.

Features

• AP Racing CP9661 six-piston calipers
• 394 x 34mm, 84-vane J Hook discs on floating hats
• About 15 lb less unsprung weight
• 18mm thick brake pads
• Pistons sized for the OEM master cylinder and ABS

What's Included

• One pair AP Racing CP9661 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 front kit fits the vehicles in the table below, which we confirmed against two sources using US model years. Essex has confirmed clearance with OEM 20x8.5 inch Front, All 19 inch APEX wheels (VS-5RS, EC-7RS, SM10-RS, SM-10), Forgeline GS1R 19x9.0 inch & 20x9.0 inch +52, Forgeline GA1R 19x9.0 inch & 20x9.0 inch +52, Forgeline VX1R 19x9.0 inch & 20x9.0 inch, Forgeline GT1-5 19x9.0 inch & 20x9.0 inch and HRE R101 20x9.0 inch. Check your wheel with the Essex wheel fitment template before ordering.

Fitment