If you owned and tracked a C5 or base C6, you probably view the front OEM brake system as a weakness of the car. They were more than adequate for street use, but didn't really live up to the performance potential of the platform overall, particularly on the Z06, or after the car was modified. While that isn't an uncommon situation with factory brakes, there simply wasn't much 'headroom' built into the system. The front calipers were heavy, two piston sliders with aluminum pistons and dust boots. They didn't respond well to heavy track use, and tended to fatigue and 'clamshell' (lose their stiffness and spread open like a clam) after repeated trips to several hundred degrees F. The pad shape these calipers used had a reasonably adequate volume, surface area, and thickness, but the shortcomings of the overall system took their toll on pad longevity and effectiveness.

On all variants of the C5 and the base C6, a conventional one-piece 325x32mm, 19 lb. front disc was used. While on paper these front discs were large enough in mass to handle a significant amount of heat, their simplistic, cost-driven design prevented them from adequately doing the job on the track. The vane design on these discs was a pillar vane, which can be thought of as a group of posts or pillars connecting the two disc halves together. The pillars are not organized linearly from the outside to the inside of the disc, and turbulence is created as air flows through and among them. Pillar vane discs are therefore not particularly well suited to heat evacuation. The goals of a pillar vane design are disc face stability for low nvh (noise, vibration, harshness), and a low cost of production. The discs are non-directional, and the same part number is used on both sides of the car. For reference, below is a picture of an OEM pillar vane disc stacked with an AP Racing competition disc. You can see the considerable difference in air gap, and the number, shape, and direction of the vanes.

For the C6 Z51, the front disc size was increased to 340x32mm, weighing in at roughly 22 lbs. The added mass of the Z51 front disc provided a larger heat sink, but the same design deficiencies of the smaller disc were still present. It therefore wasn't much more efficient at removing heat from the system when being flogged.

Some of the common results of running the C5/Base C6 system hard on the track were severely tapered brake pads, pads quickly burning up, pad fade (firm pedal, but car won't slow), fluid fade (soft brake pedal due to boiled fluid), cooked dust boots, and quickly cracked discs. All of these problems are directly related to the overall brake system having inadequate heat capacity and cooling for heavy track use. When the OEM brake system was retained and tracked/raced, the system required considerable maintenance, and owners wasted a significant amount of time and money bleeding brakes, replacing pads and discs, and losing valuable track time.

Owners tried to work through these issues via several means: installing stainless steel pistons in the OEM calipers, stainless steel brake lines, high temperature race pads and brake fluid, and aftermarket brake discs. Ultimately though, most serious track enthusiasts were far better served by replacing the entire front brake system with an aftermarket kit designed specifically to handle the rigors of track use. Our Essex Designed AP Racing Competition Brake Kits have also been a popular choice for all of the reasons outlined above.

On the rear of the C5/Base C6, a simple one piston slider caliper and 305x26mm, 14.2 lb. discs were employed. Given their layout, modern Corvettes are not particularly hard on rear brakes, and many people found the rears adequate. These discs were on the small side for a car of this potential however, and again became more problematic as the car was modified and run on the track. A substantial number of owners did run into heat-related issues. Combined with the diminutive discs, the pads on the rear were quite small in terms of overall volume and surface area (see below), which can lead to heat dissipation issues. Also of note, drivers who left Competition Mode engaged ran into rear brake overheating from time-to-time, as the car tried to correct yaw by engaging the inner rear wheel brakes.

For the Z51 rear brakes, the caliper remained the same, but the rear disc diameter was increased to a more adequate 330x26mm, and 20 lbs., alleviating some of the heat issues. For those whose problems weren't solved, there are a number of options available, including a complete Essex Designed rear competition brake system we'll be releasing shortly.

And for a final note to those who care about aesthetics, the C5 & Base C6 brakes were just plain ugly!

C6Z06- An upgraded brake system?

Everyone knows that the C6 Z06 is an absolute monster on track. The LS7 and improved chassis turned the platform into a bullet, and it's not uncommon for the C6 Z to dominate the time sheets on any given day. To match the prodigious output of the LS7, GM 'upgraded' the brakes to a completely new system. While the general design direction of the new brake system was correct, the implementation was not, resulting again in an inadequate system for a car with such an extreme performance envelope.

The front and rear calipers were fixed six and four piston units by PBR, a step in the proper direction. The goal was to provide a firmer pedal feel, more total pad volume, and more leading pad edges to bite into the disc. The final product didn't work out quite as planned however. Despite looking the business, the front and rear calipers were heavy, not terribly stiff, and overly complex featuring the now dreaded brake 'padlets,' which provided inadequate volume for heat absorption (most owners run a one-piece pad when available).

While the calipers presented a list of problems, the discs were an even bigger problem. At 355x32mm, the front disc size was an excellent choice. It's been proven over and over since the C6 Z's release that a quality, optimized, floating 2-piece racing 355x32mm disc is a perfect choice for even the fastest cars and drivers. A one-piece, drilled disc that has vanes pointing in the wrong direction isn't such a great choice however, but that's what came on the car from the factory. If you drive your car on the track, 'just say no' to drilled discs! They will crack more readily than a slotted disc, regardless of whether or not the holes were cast into the disc (a popular myth propagated by Porsche road car owners worldwide, but refuted by just about every winning racecar in the world). Ultimately, someone in marketing at GM won the battle for the drilled discs because they looked really cool. Even more egregious than the drilled holes however, was the fact that the same directional disc was used on both front corners of the car. In other words, the directional vanes were actually spinning in the wrong direction on one side of the car!

- See more at: http://www.essexpartsblog.com/news/c....ARJysqRp.dpuf