The braking advantage by having the innovative cooling method
  • With cooling air flowing from both the inner and outer side of the disc, there is an significant improvement in cooling capability.
  • The cooling effect strengthen the disc resistance from thermal cracking and helps prevent brake judder from occurring.
  • With quick and efficient cooling, the full potential of the brake pads can be achieved.
  • All the brake components last longer.
Is it better to change the brake pads and brake discs at the same time?
About the cooling ability and its effect on disc distortion

By using dual active ventilation, the cooling capability and judder resistance improves significantly compared to the standard ventilated disc.

For standard ventilated disc, the cooling air flows from the inside of the brake hat. The DAV disc has a superior structure which takes in the air flows from both inside and outside of the brake hat. The result is significantly better cooling performance. Moreover, the heat build-up which leads to brake judder can be prevented by proper cooling. When the DAV disc is compared to a standard ventilated disc, the DAV has higher disc resistance from thermal cracking, which helps prevent brake judder.

■ Standard ventilated disc


Cooling air flows from the inside of the brake hat.

■ DAV disc (Dual Active Ventilation)


Cooling air flows from both inside and outside of the brake hat.

The frontal view comparison of the standard ventilated and DAV discs. The disc shape is different for each model number.
  • ■ Side view of a standard ventilated disc
    ■ Side view of the DAV disc

The deformation amount of the disc is proportional to the ratio of the width of the friction surface of the disc (A) and with the diameter of the hat of the disc (B).
On a standard ventilated disc, the hat (B) has a smaller diameter compared to the width of the friction surface (A). When deformation occurs from heat, there is a bigger impact on the outer edge of the disc. On the other hand, the DAV disc has a smaller width on the friction surface (A) with a bigger hat diameter (B). The impact of the deformation at the outer edge of the DAV disc is comparatively smaller than that of standard ventilated disc. The braking surface is sloped in the opposite direction compared to the OEM, therefore there is minimum effect on the braking feel.

Cooling performance test data
  • Testing was done to research the cooling effect of the DAV disc. After warm-up runs were done, brake testing was done 8 times. Brake disc temperatures were measured at two different points. The first measurement was taken immediately after the car came to a complete stop from 150 km/h under hard braking. The next measurement was taken after a cooling run for about 400m at 80 km/h.The temperature of disc and caliper on DAV fitted side was lower than that of normal type fitted side. The superior cooling effect of the DAV disc was proven effective for both the caliper and disc temperatures.
  •   standard SD rotor DAV SD rotor
    temperature of rotor 553°C→396°C 542°C→368°C
    temperature of caliper 185°C→164°C 163°C→144°C

This test was carried out using a Subaru BE5 Legacy on a closed test course. The DAV disc was fitted on the right axle and the standard ventilated disc was fitted on the left axle.

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