From – Bob

I see you have some new products!  I've been looking for a good brake duct kit and have a few questions on yours. The photo on the web site only shows the plate that attaches to the spindle.  Are hoses and some kind of brackets for mounting the inlet end of the hose included in the kit too?  If not, what size hose is needed?  One brake engineer told me it's not the greatest idea to completely close off the eye of the rotor unless there's at least a 4inch hose supplying air. The claim was if a smaller hose is used the rotor can actually be starved for air and could pump more if the eye of the rotor is open.  Got any comments on that?

Hey Bob –

We offer both a Brake Duct kit that fits on the spindle and a Universal Brake Duct Hose Kit to get air from the front fascia to the duct.  Both come with mounting hardware and instructions.

Here are the part numbers for my Brake Duct kits
KB-71200 94-‘04 GT, V-6 & Cobra
KN-71600 2005 on --
And - Universal fascia to brake duct hose kits
KB-71300S W/ 600⁰ Silicone aircraft hose
KB-71300N W/350⁰ Neoprene aircraft hose.

The hose size on my brake kits is 3".  I have been using the 3" hose for many years with good results.  The FR500S Mustangs I engineer for the Mustang Challenge Series use a 4" brake hose except, the restrictiveness of packaging due to the spindle and the round 4”outlet at the rotor only puts about 70% of the cool air directly into the center of the rotor.  The rest hits the inner surface of the rotor.  When I developed my kit, by using the 3" hose I was able to make the outlet oval and put all of the air into the center of the rotor or the "eye" as the brake engineer referenced.

Something the brake engineer may not have taken into consideration is that the air from the fascia to the brake duct is under pressure; the faster you go the more pressure and the more air.  For most drivers our 3" duct have shown to be more than adequate in keeping brake temps in range.  Also in the OE application, there is a "dust shield" that covers the inner surface and eye of the rotor.  Anyone who is running open track, if you can’t afford brake ducts - at least take off the dust shields.  My recommendation though is anyone running open track needs brake ducts to cool the brakes.  Brake Ducts will easily pay for themselves in longer pad and rotor life and most importantly – safer surer stops.

I would encourage caution when comparing brake duct kits as many of the kits I have seen in the market only put the air on the inner surface of the rotor which causes a temperature differentiation between inner and outer surfaces of the rotors - not the best solution.   Putting the air into the center or the “eye” of the rotor cools both rotor surfaces equally – as well as helping to cool brake pads, caliper s and fluid.

As a side note: when we have run both my CSR-69 with 3" ducts and the FR500S Mustang Challenge racecars with 4" ducts very hard at the same track on the same day - both have Brembo brakes w/14" rotors - the brake temps were pretty much the same and very consistent in 950⁰ to 1050⁰ rotor temp range.