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In-stock items ordered before 1 pm PST typically ship the same day.

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Free shipping to the continental US on orders over $400 (some exclusions apply)
In-stock items ordered before 1 pm PST typically ship the same day.

Boxmount Brake Duct Kit for BX11/BX1175


Product Description

Boxmount Brake Ducts

If your pads spend a lot of time near their MOT (Max Operating Temp) functional brake ducts can double pad life. If you are occasionally experiencing mild fade now, these brake ducts will probably reduce or eliminate it.

Our patented Boxmount caliper mounting system leaves a nice big space for air to flow where it’s needed most – the center of the rotor. That space is blocked by traditional plate style brackets. The increased cooling air flow also passes across the hub, helping extend hub life. It then flows out through the rotor vanes and through the caliper, cooling the both sides of the disc evenly. Cooling just one side of the rotor doesn’t work.  After testing 2 and 2.5″ diameter ducts and the long 40″ hose, we found those diameters simply did not flow enough to make a meaningful difference in cooling. The longer the hose, the more restriction to airflow. So 3″ is the absolute minimum. Heavier cars will often use 4″ diameter ducts. Sports prototypes often multiple 4″ ducts on each wheel. So while 3″ might seem like overkill for the little NA/NB, our experience has shown that its the minimum required to be effective.

Our extensive endurance racing experience (2x Thunderhill 25hrs champions) taught us that brake cooling is key. The Boxmount system was specifically developed to allow better cooling. The entire system is integrated. Ducting this direct and efficient isn’t possible without our patented Boxmount caliper brackets.

The BX11 Duct Kit requires relocating the brake hose in your BX11 brake kit calipers. All the necessary fittings are included
BX11 Duct instructions

The BX1175 Duct kit includes new backing plates designed to keep the high pressure cool air mass directed through the rotor vanes and caliper.
BX1175 Duct instructions

Compatible ONLY with our Boxmount Big Brake Kits. Order together with our BX11 or BX1175 brake kits and receive free shipping in the US

Hose Kit
Recommended shopping list from Aircraft Spruce for connecting your ducts to the nose of the car. This assumes a flat plastic style air dam.

  • 05-29812  : 3″ duct hose x 7′. You will need about 3.5′ per side
  • 10350-12  : 2x 3″ Duct flanges
  • QS200-52H  : 4x Clamps to secure hose to flanges


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