GT1 Ultimate Brake Kit
Traditionally, the 928 owner's brake upgrade choices were limited to upgrading to the brakes found in the next-newer generation of 928's. 928 and 928 S owners upgraded to brakes for a 928 S4 or GT, and S4/GT owners went up to GTS brakes. And there it stopped.
But wheel upgrades haven't stopped as 18" and 19" wheels are now fairly common, and the brakes have not kept up. And if you're a racer - you may have found like many of us that you can over-cook the GTS brakes. But no more.
928 Motorsports LLC® in collaboration with Brembo has developed a new brake kit for the 928, dubbed the "GT1" big brake kit.
Not to be confused with others' "big brake" kits sporting 304 or 322mm rotors, these GT1 brakes are a whopping 355mm rotor with a lightweight two-piece rotor and hat combination.
ROTOR DIAMETER: the easiest part of the upgrade to see. Larger diameter rotors Increase the thermal mass (decreasing brake fade) and improves stopping power by increasing the effective radius (see below). And they look AWESOME through aftermarket 18" wheels!
EFFECTIVE RADIUS: the benefit received when using a longer wrench to turn a tough bolt. In this case, using a longer wrench to stop the rotor from spinning. The longer the effective radius of the caliper/rotor combination, the more powerful the brakes. Not the same as the radius of the rotor, but the distance from the center of the rotor to the center of the caliper piston.
ROTOR WEIGHT: although increased thermal mass helps decrease brake temps, increased weight means more unsprung weight and higher rotational inertia - both which hurt performance. The answer is a two-piece rotor/hat combination that gives the rotor the thermal mass it needs, but lightens the assembly for less unsprung weight and inertia.
A WORD ABOUT 4-PISTON vs. 6-PISTON CALIPERS
There is a common misconception that 6-piston calipers have better stopping power than 4-piston calipers. That isn't true. The increase in stopping power comes from the increase in rotor diameter, effective radius, and the hydraulic gain of the system. Brake pad size and the number of pistons in the caliper have nothing to do with braking effectiveness.
Most 6-piston calipers flex more, cost more, and fit inside fewer wheels - making wheel fitment a challenge. Brake pads for a 6-piston caliper also cost more, and are offered in only a few materials. The only merit they have is that the brake pad on a 6-piston caliper is larger, so they last longer between pad changes - which is a valuable feature if you are endurance racing. But, it also means they cost more at each pad change.
On the other hand, our Brembo 4-piston caliper is stiffer, and requires 10mm less of clearance than the 6-piston model, so it will fit inside virtually all 18" wheels. It has a broad selection of brake pads available for it, and they cost less. Additionally, the 4-piston caliper features the quick release pad design, which is a nice feature for customers tracking their cars.
DESIGNED WITH YOUR MASTER CYLINDER IN MIND
928 MOTORSPORTS QUALITY
There are several reasons that a two-piece floating disc assembly is of benefit. First, using an aluminum bell for the hub section of the disc saves a great deal of weight. Since this is both rotating and unsprung, it benefits the acceleration, braking, and handling of the vehicle. Secondly, it is better able to handle the large temperature changes that a brake disc experiences, and provides a better thermal break to reduce wheel bearing temps.
The mounting system is designed to allow a specific amount of float in both radial and axial directions. Brembo has engineered special springs that are used on every other fastener in order to slightly preload the assembly. This has been done to prevent excessive noise from the system during street use.
Brembo supplies a directional curved vane disc in these assemblies. The discs are installed with the vanes running from the inside to the outside diameters in the direction of rotation. Orienting the disc in this manner creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This greatly enhances the disc's ability to dissipate heat.
WHAT ARE THE ADVANTAGES OF DRILLED AND SLOTTED DISCS?
COMPLETE KIT INCLUDES
Multiple Brake Pads Available
THIS IS A SPECIAL ORDER ITEM
SHIPPED IN MATCHED BOXES:
GT1 Ultimate Brake Kit
* Domestic US shipping shown. International shipping will be calculated based on location.
Phone: (920) 485-0928
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