The BMW E46 M3 and non-M 3-series chassis have a minor amount of factory brake cooling - but we can always add more. No matter how much aftermarket BBK you throw at them, the extra brake cooling these Vorshlag E46 brake cooling deflectors add is tremendous, and cuts down on pad wear, rotor overheating, and fluid boiling. This extends the brake and rotor life, and adds a bit of cushion to over-zealous late brakers within their track sessions.
In the past Vorshlag offered "ducted hose" style brake cooling backing plates, inlet ducts, and tubing for a number of cars for many years - and we still do for some chassis. This is how everyone cooled the brakes for track use for many decades.
There are issues doing that "old school" way, 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 cooling "deflector" kit for the BMW E46, which takes the place of the factory dust shield and "bearing cage". This takes the high pressure air stream from the front of the BMW E46's factory "inlet ducts" and redirects that airflow into the inside of the rotor. The rotor vanes act as a pump and push the air out of the rotor, cooling it from the inside-out.
This design completely replaces the factory dust shield, and in doing so we have built in two heat shield sections that leave an air gap between the deflector and the two ball joints - one on the tie rod and one at the control arm. You can see these heat shield sections in the image above, with the rotor removed.
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 every car we have built these for and tested on track they outflow and outcool even 4" ducted brake hose kits!
All Vorshlag brake cooling deflectors kits are built in-house, with CNC cut plates bent to fixtures we keep on hand. 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.
FEED IT: BRAKE INLET DUCTS OR TUNNELS
The brake deflectors need to be fed cooling air from a high pressure source, such as the front of the car or tunnels in an undertray or splitter.
The easiest way is to just re-use the OEM brake inlet ducts. BMW created a perfectly adequate brake inlet duct on all E46 models, as shown above. This has a smooth bore plastic duct that feeds air right towards our brake deflector.
These ducts dump out this high pressure air into the front wheel well and the deflectors redirect that to the inside of the rotor - better than the OEM dust shields.
Alternatively a well placed "tunnel" molded into an undertray or added to a front splitter can feed as much or more air to the deflectors. If your E46 is a race car and has a splitter - and your class rules allow for tunnels - point them right at the deflector, like in the S197 Mustang picture shown above. You can also see our S550 Brake Deflector Kit for ideas on tunnels.
INSTALLATION INSTRUCTIONS
Installing the Vorshlag E46 front brake deflector cooling kit is easy, but it might be best done at the same time as you add new front wheel hubs.
First step is to remove the front brake caliper and rotor. Just hang the caliper with a J-hook out of the way, so it isn't hanging by the brake line.
Next, it is time to pull the front hub off, to gain access to the the factory dust shield on the back side of the rotors. The stock dust shield is behind the front hub, so you have to remove the main hub nut. Bring a big 1/2" impact gun.
The next step might involve a slide hammer. Depending on how old the hubs are on your E46.
The hubs on this red 2004 ZHP weren't that old and they came off easily - as did the inner race. We were able to reinstall these hubs and checked them to have no "play". If in doubt, have a spare set of new hubs ready to go on - Rockauto replacements from Timkin or SKF are a safe bet.
Now that you have access, the large factory dust shield is unbolted and set aside - none of it will be reused. We need to clear the path for the cooling airflow to reach the rotor, so the old bits have to go.
Next, the brake deflector is bolted onto the E46 spindle (M3 or non-M) with the 3 factory bolts. This goes in place of the dust shield, as shown above. Then the hubs are reinstalled - now would be a great time for a fresh set of Vorshlag screw-in wheel studs.
The last step is to re-install the brake rotor and caliper, then the wheel. We test fit this brake deflector inside 17" and 18" wheels, to fit what our customers will likely use.
