These brake proportion valves enable very precise and sensitive adjustment and regulation of the % braking force (pressure) applied front to back or left to right Brake Bias in single cylinder brake master cylinder set ups -depending on how this is installed. This enables the user to situate the valve within reach of the driver enabling immediate changes of brake bias with changing track conditions during a race or immediately before leaving the pits with changing weather conditions. This greatly improves handling particularly on entry whilst negotiating bends under braking.
IT IS THE RESPONSIBILITY OF THE PERSON INSTALLING AND BRAKE COMPONENT OR KIT TO DETERMINE THE SUITABILITY OF THAT COMPONENT OR KIT FOR THAT PARTICULAR APPLICATION. IF YOU ARE NOT SURE HOW TO SAFELY USE THIS BRAKE COMPONENT OR KIT, YOU SHOULD NOT INSTALL OR USE IT. DO NOT ASSUME ANYTHING. IMPROPERLY INSTALLED OR MAINTAINED BRAKES ARE DANGEROUS. IF YOU ARE UNSURE, SEEK EXPERT PROFESSIONAL QUALIFIED HELP OR RETURN THIS ITEM TO US. YOU, OR THE PERSON WHO INSTALLS THIS PRODUCT, MUST KNOW HOW TO INSTALL OR PROPERLY USE THIS PRODUCT. IT IS NOT POSSIBLE TO OFFER TECHNICAL ASSISTANCE OVER THE PHONE TO UNDERSTAND OR FORESEE ALL THE ISSUES THAT MIGHT ARISE IN YOUR SPECIFIC INSTALLATION. RACING EQUIPMENT AND BRAKES MUST BE MAINTAINED AND SHOULD BE CHECKED REGULARLY FOR DAMAGE, WEAR OR FATIGUE.
To complement these valves, we have a range of other products available in our online store.
UNDERSTANDING THE PRODUCT
The proportioning valve is one of the least understood devices bolted on to a race car. They are often viewed as restrictor valves, which they are not. Understanding, from a functional viewpoint, will allow the driver to take full advantage of it;s properties for a better race car set up.
At low pressures (up to about 150 PSI), these Proportion valves operate as a simple hydraulic through coupling with a 1:1 inlet to outlet pressure flow rate. The various lines coming off from the 45 degree line shown in the below chart that once a certain pressure is reached, with a further increase in line pressure (i.e. more braking) the Proportion valve starts to operate and a further increase in line pressure results in a reduced flow rate of 60% from inlet to outlet from that point on wards.
The Adjustment knob or lever adjusts the point at which this switch over from a 1:1 flow rate to a reduced 60% flow rate occurs.
The dual slope line performance characteristic gives one advantage over the brake pedal box adjustable balance bar type proportion system as it can be fine tuned for better front to brake balance under both light and heavy braking. A particular setting of a pedal box brake bias bar gives you a fixed front-to-rear brake balance (such as 70/30 – 70% front to 30% rear). Under both light and heavy braking, the balance remains the same.
However, the loading on the front and rear axles does not remain the same under different braking conditions. During heavy braking, there is a large load transfer from the rear to the front axle. As the load increases on the front axle, you want a higher percentage of the braking force on the front axle. The bend in the above graph lines for the Proportioning valves allows this progressive braking force proportioning to happen when the valve is placed in the line for the rear callipers – during heavy braking, a higher percentage of the braking force is proportioned to the front calipers.
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