Well, what a massive last few months it has been for everyone at Team Jenkins HQ.
- Troy and Ben Jenkins
Owners / Drivers of Team Jenkins Motorsports
Chase Bays sells many brake component products, and in doing so we receive many questions regarding the function of our setups. There is a lot of misinformation and misunderstanding when it comes to brake hydraulic function. Here are 4 facts to help better understand braking.
1. Master Cylinder Bore: Larger vs Smaller
One of the most common misconceptions is that a larger master cylinder will create more pressure. While a larger master cylinder creates a larger displacement, it takes more force to create the same pressure as it would with a smaller bore. The result after adding the larger master cylinder bore is a harder pedal which requires much more pedal pressure to create the same amount of brake clamp force. This result displays itself as a combination of undesirably high force and unpredictable braking response. In more specific terms, moving from a 3/4" master cylinder to a 1" requires 77.7% more force on the push rod to reach the same amount of clamping pressure. Our goal was to develop a product that balanced the entire system. We factored in pedal force, system pressure, and lever travel and the 7/8” Wilwood fit the bill in every category.
2. Eliminating the Brake Booster: Impact on Braking Function and Pedal Feel
It is not uncommon for us to hear people say that eliminating the booster will cause the pedal to be too stiff for reasonable braking control. While we cannot disagree that some people do have this issue after eliminating their booster, their issues are always due to improper design and setup. Every bore has an appropriate pedal (or lever) design required to produce a certain level of pressure. The key to a great pedal feel and more controlled braking is a properly balanced master cylinder bore in relation to the pedal ratio (the length from the pedal swing mount to where it attaches to the master cylinder) used, with an adjustable proportioning valve before the rear brake lines.
In a brake boosted setup, the purpose of a brake booster/vacuum servo is to reduce the amount of pedal pressure required to push the master cylinder. In doing so it creates inconsistent braking because of varying vacuum levels within the chamber. It is very common in race cars (and show cars) to eliminate the brake booster to attain more consistent and controlled braking. After removing the booster the pedal does get stiffer but it is still reasonable for street and track use (much like the difference in pedal feel after changing from stock to an aftermarket clutch). The stiffer pedal feel allows better brake modulation now that there is no booster between the driver and the master cylinder. Our Brake Booster Eliminator kit ensures the master cylinder size is paired properly with the pedal ratio on street cars. Chase Bays offers a Brake Booster Eliminator Kit, Adjustable Proportioning Valve, and Brake Line Relocation Kit for various chassis.
To see more about these Chase Bays brake products, click HERE
3. Cross-Drilled and Slotted Rotors: The Basics
Cross Drilled Rotors
Cross drilled rotors are OE-style blank rotors that have been cross drilled to allow heat to escape that builds up between the brake pad and rotor through the drilled holes and out the mid rotor vent channels. Many people prefer drilled rotors because they like the look and consider it a good upgrade over an OEM blank rotor. The problem is that the integrity of the rotor is moderately compromised which combined with extreme temperatures and pressure can allow them to crack between the drilled holes. Thus even though drilled rotors are specifically designed to expel hot gases, most available on the market are not built properly and the holes serve merely an aesthetic purpose. If you are set on buying a drilled rotor, we recommend a quality brand such as DBA, Brembo, or Wilwood.
Slotted brake rotors are a great alternative to drilled rotors because they serve the same purpose of expelling hot brake gas, but since they retain the strength of the rotor, they are not prone to cracking in the same fashion as cross-drilled rotors. They are also easier on the brake pads in terms of wear.
What's best for the street vs the track?
Most of our customers will notice more of a difference in stopping performance by changing the brake pads than the rotors. The advantages from cross drilled and slotted rotors comes during extremely hard and repetitive braking such as in competition use. For street use, we believe the best bang for the buck is to get a quality set of slotted brake rotors, suitable brake pads for your driving style, and replace your rubber fender well brake lines with stainless steel brake lines.
4. Brake Pad Quality Breakdown
There are different types of brake pads for different purposes. The qualities we demand from a street pad is completely different from what we need out of a race pad. Day-to-day street driving pads generally demand the following characteristics:
- Never make any noise
- No dust on our fancy wheels
- Good cold bite on the way to work
- Effective in the rain and snow
- Last 100,000+ miles
- Never wear out rotors
However, our priorities shift when the weekend rolls around. We want our race pads to have the following characteristics:
- Enough heat capacity to never fade after repeated lapping on a racetrack
- Predictable torque response for precise brake pedal feel and modulation
- No required bed-in or preparation
- Immediate release from the discs when we let off of the brakes
- No uneven pad deposits or scoring of the rotors
- Little to no wear as temperatures increase
Each driver must determine the most important pad characteristics for the type of driving he or she will be doing and choose a pad strategy with acceptable compromises. Out of often hundreds of different pad options, each pad compound will exhibit different characteristics and potential drawbacks. The goal is to find a happy medium based on how the car us used. Every situation is different.
With this article, we hope to help people understand braking components better so they can build a functional system suitable for their demands. If you would like to see a full article on specific pad types including their strengths and drawbacks to help you determine which is best for each type of driving…let us know!