Brake System
Brake System
The standard brake system of the new 911 Turbo (997) is more generously dimensioned than on the previous 911 Turbo (996) as a result of the increase in performance, and represents a completely new development. In addition to the larger internally vented brake discs on the front and rear axles, the brake force distribution of the new 911 Turbo has also been optimized by use of a new 4-piston rear axle fixed caliper. The design-related potential offered by the current 911 Carrera models with respect to dynamic axle load transfer when braking is thus used to further increase brake performance.
Front Axle Brake
The cross-drilled and internally vented grey cast iron brake disc has a diameter of 350 mm and is 34 mm thick. A new 6-piston fixed caliper is used with a pad area which is 42 % larger than on the 911 Turbo (996).
Rear Axle Brake
To further increase braking power, the brake disc diameter has been increased to 350 mm, and the pad surface areas and piston diameters have been enlarged. As a result, the design of the 4-piston brake caliper had to be revised. To mount the "pulled brake pads" and increase rigidity, two additional bars are fitted over the brake pad slot. The brake caliper must be removed in order to change the brake pad.
Brake Cooling
Compared with the previous 911 Turbo (996) model, brake cooling at the front axle brake has been improved by enlarging the brake air spoiler and optimizing the underbody panel. With these measures, more air reaches the brake disc directly and the brake is cooled more effectively. For the first time in a Porsche series vehicle, the 911 Turbo is provided with active ventilation of the rear axle brakes. The cooling air is routed under the vehicle body through additional openings and a flow channel as well as via special control arm spoilers so that it is directed in a targeted way at the rear brakes. This made it possible to increase cooling efficiency by 14 %.
Tandem Brake Booster
Similar to the current 911 Carrera 4 (997) models, the new 911 Turbo is also provided with a 9-inch tandem brake booster instead of a 10-inch single brake booster. The compact tandem design made it possible to further increase brake booster performance compared with the previous model. The total surface area of the tandem brake booster is around 45 % larger than that of the single brake booster of the 911 Turbo (996). As a result, it was possible to reduce the pedal forces by approx. 20 % in conjunction with optimized brake force distribution and correspondingly modified dimensions.
Brake Master Cylinder
In order to attain an optimum pedal feel with a more precise working point, the diameters of the brake master cylinder have been increased to 26.99/26.99 mm.
Vacuum Pump
A mechanical vacuum pump has been installed on the engine instead of using a vacuum amplifier for providing the brake booster vacuum. This design enables a high and constant level of vacuum supply and subsequent effective brake boost even when the most unfavorable underlying conditions apply, e.g. low barometric pressure at high altitudes, under boost pressure and in highly dynamic driving involving a high proportion of full-load operation, e.g. on race tracks.