Vorshlag has offered "ducted hose" style brake cooling backing plates, inlet ducts, and tubing for a number of cars for many years - and we still do. This is how everyone cooled the brakes for track use for many decades. Well there are issues doing that, namely the corrugated hose feeding a ducted backing plate has some serious flow restrictions, plus the front tires and wheels can rub holes in them at steering lock. But there is another way...
This is our brake "deflector" cooling kit for the BMW E46 M3 (2001-2006) for the stock brakes or 14" or larger big brake kits.
How do they work? The incoming airflow from OEM brake inlet ducts in the front fascia as well as from under the car feed air to these air deflectors, which then pump air inside the rotor hat. You will need to remove (and/or modify) the factory dust shields inside the rotors, obviously.
This massive volume of air cools the hubs then the vanes inside the vented rotors pull air through like an air pump, which cools the rotors and pads. It works surprisingly well. On our S550 Mustang in track testing, this deflector design worked better than our 4" ducted hose brake cooling!
These deflectors are built 100% in-house here at Vorshlag. This version takes considerably longer to form the aluminum and rivet them together than some of our other versions - and is priced accordingly. Remember: There are no 3" or 4" corrugated "consumable" brake cooling hoses needed. Those hoses can get smashed by tires while near steering lock, and have to be replaced regularly. This kit is still less costly than our ducted backing plate + hose kits.
BRAKE INLET DUCTS OR TUNNELS
The brake deflectors need to be fed cooling air from a high pressure sources, such as the front of the car or tunnels in an undertray or splitter.
BMW created a perfectly adequate brake inlet duct on the E46 M3, as shown above. This has a smooth bore duct that feeds air right towards our brake deflector.
Alternatively a well placed "tunnel" molded into an undertray or added to a splitter can feed as much or more air to the deflectors. See our S550 Brake Deflector Kit for ideas on tunnels.
Installing the Vorshlag E46 M3 brake deflector kit is easy if you have the factory lower control arms. We designed this on a car with 14" diameter StopTech rotors and 4 piston ST-40 caliper, but works on stock M3 or virtually any aftermarket big brake kit. 18" diameter wheels are required to clear the bottom of the shield, but if you are running 17" wheels they can be trimmed or bent at the bottom.
First step is to remove the factory dust shield on the back side of the rotors. The stock dust shield is behind the front hub, so you have to pull the caliper, rotor, then remove the main hub nut. Bring a big 1/2" impact gun.
The OEM dust shield needs to be cut at the portions show to allow for adequate airflow from the deflector to the backside of the rotor and front hub.
After the dust shields are trimmed reinstall those, then the hubs, the rotor and caliper.
We designed these deflectors to mount with a U-bolt and worm gear clamp, as shown above. There is some adjustability left to right - get the deflector as close to the rotor as you can, but test with the wheel turned to full lock in both directions.
Optionally you can remove the "V" portion shown below for even more airflow to the rotor.
This allows the dust shield to cover both ball joints (control arm and tie rod) while getting the maximum amount of airflow to the inside of the rotor.