We wanted to dive into the design and manufacturing of our fog light ducts and backing plates for the ND brake cooling kit.  They are a unique and neat part with an interesting design and impressive manufacturing process.


The Data


We start with a scan of the rear side of the front bumper with the fog light removed.  We also scanned the knuckle for the backing plate and duct design.  With this data, we can design the duct and backing plates!


The Design


To keep costs down on the backing plate, we opted for a stainless backing plate with a specifically designed carbon duct to aim airflow into the center of the rotor. 

On the fog light duct side, the only option we saw for a nice unit given the space required a completely composite design.  With the scan data we took previously, this was accomplished using surface modeling.   Tabs were added for bolting the duct to OEM bumper locations.


The Manufacturing


The backing plate is produced out of stainless sheet which is the same thickness as the OEM backing plate.  These backing plates are cut from a CNC laser.  The ducts are produced from pre-preg, 2x2 twill, autoclave cured 3k carbon.  These are produced using a two-piece mold built off our 3D printed unit which was used as a plug.  The duct is then riveted onto the stainless backing plate using rivets.


The fog light ducts are also produced from pre-preg, 2x2 twill, autoclave cured 3k carbon fiber.  At the time, we were unable to print these units accurately so we had to CNC plugs directly from our CAD using a 5-axis mill.



After producing both plugs, we were able to produce the molds from these units.  The molds for each duct consists of (4) pieces per side to properly produce the ducts from carbon fiber.



Using the molds, we are able to produce a duct.  The mounting locations are twice as thick as the duct body to increase rigidity for the mounting locations.



The Parts!


The ducts are produced with pre-preg carbon, which offers superior strength, weight, uniformity, repeatability, and cosmetics when compared to hand, wet lamination.  It is a bit more expensive but offers a lot of positives.  The negatives are cost, the shelf life of the actual carbon before it is cured, and the necessity to use an autoclave.  Below are some photos of the carbon ducts directly out of the mold.  Note how the finish is a bit hazy/matte.


After curing, these units are removed from the mold and polished to a shine.

A lot of work goes into producing ducts like these from scratch.  It was a very fun and exciting project that pushed our abilities!  If you have any questions, please don't hesitate to send us an e-mail.  The full kit is located here for purchase and through our various vendors: https://www.verus-engineering.com/product-page/nd-mx5-miata-brake-cooling-kit