Brake Modification To Reduce Fade
High performance brake components provide enhanced stopping power by improving friction while reducing brake fade. Improved friction is provided by lining materials that have a higher coefficient of friction than standard brake pads, while brake fade is reduced through the use of more expensive binding resins with a higher melting point, along with slotted, drilled, or dimpled discs/rotors that reduce the gaseous boundary layer, in addition to providing enhanced heat dissipation. Heat buildup in brakes can be further addressed by body modifications that direct cold air to the brakes.
The "gaseous boundary layer" is a hot rod mechanics explanation for failing self servo effect of drum brakes because it felt like a brick under the brake pedal when it occurred. To counter this effect, brake shoes were drilled and slotted to vent gas. In spite of that, drum brakes were abandoned for their self-servo effect. Disks do not have that because application force is applied at right angles to the resulting braking force. There is no interaction.
Adherents of gas emission have carried that belief to motorcycles, bicycles and "sports" cars, while all other disk brake users from the same automotive companies have no holes through the faces of their discs, although internal radial air passages are used. Vents to release gas have not been found on railway, aircraft and passenger car brakes because there is no gas to vent. Meanwhile, heavy trucks still use drum brakes because they offer more heat dissipation than disks that would fit in the same space. Railways have never used internal expanding drum brakes because they cause skidding, causing expensive flat spots on steel wheels.
Both disc and drum brakes can be improved by any technique that removes heat from the braking surfaces.
Drum brake fade can be reduced and overall performance enhanced somewhat by an old "hot rodder" technique of drum drilling. A carefully chosen pattern of holes is drilled through the drum working section; drum rotation centrifugally pumps a small amount air through the shoe to drum gap, removing heat; fade caused by water-wet brakes is reduced since the water is centrifugally driven out; and some brake-material dust exits the holes. Brake drum drilling requires careful detailed knowledge of brake drum physics and is an advanced technique probably best left to professionals. There are performance-brake shops that will make the necessary modifications safely.
The Bugatti Veyron for example has turbine-cooled brakes that reduce fade to almost nothing considering the speeds it is braking from.
Brake fade caused by overheating brake fluid (often called Pedal Fade) can also be reduced through the use of thermal barriers that are placed between the brake pad and the brake caliper piston, these reduce the transfer of heat from the pad to the caliper and in turn hydraulic brake fluid. Some high-performance racing calipers already include such brake heat shields made from titanium or ceramic materials. However, it is also possible to purchase aftermarket titanium brake heat shields that will fit your existing brake system to provide protection from brake heat. These inserts are precision cut to cover as much of the pad as possible. These Titanium Brake shims are an easy to install, low cost solution that are popular with racers and track day enthusiasts.
Another technique employed to prevent brake fade is the incorporation of fade stop brake coolers. Like titanium heat shields the brake coolers are designed to slide between the brake pad backing plate and the caliper piston. They are constructed from a high thermal conductivity, high yield strength metal composite which conducts the heat from the interface to a heat sink which is external to the caliper and in the airflow. They have been shown to decrease caliper piston temperatures by over twenty percent and to also significantly decrease the time needed to cool down. Unlike titanium heat shields, however, the brake coolers actually transfer the heat to the surrounding environment and thus keep the pads cooler.
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