I put the tape around the ducting so the floor and cables don't cut trough.
Install your floor back on the car.
6: Trie rip the duct to the lower control arm. I used 4 tie rips , you can only see 3. I used one to tie the 2 tie rips together to stop them sliding over the Control arm.
Attachment 320392
7: Point it at the center of the disc.
Attachment 320393
With the brake ducts attached to the front lower control arms, they are in line with the backplate air inlet.
8: From the side it should now look like this
Attachment 320394
Now you can make some custom backplates.
Or just make the ends of the brake ducts oval and lodge it in the back plate opening behind. With the length @ 42 Cm - 17'' it's just right.
Yes, i know what you are thinking. That won't work, it will be all over the place...But i tested it, 900Km hard drivin' so far and they stay in to place.....Unbelievable but true.
Now to make your Custom Backplates
9: Remove your calipers, by undoing two 18mm bolt thats hold the caliper. you can remove the caliper and use some zip ties to hang it somewhere.
I stole a few pics for Longtrans BBK install
10: Remove the brake disc. 6mm hex on the face of the rotor.
11: Mark the back of the backplate where you will create the opening and mounting points for the brake duct first before removing it.
12: Remove the back plate.
13: Work you magic, Do some riveting and attach your 'ring' to the backplate to accept the ducting hose. Make sure with a bit measuring and fitting that your 'ring' installation does not touch the hub and that you leave some space to later attach the hose and clamp.
Attachment 322851
14: The red is the metal i removed to get the extra air to the disc. The red arrow point to the 'ring' it's kinda hard to c.
Attachment 322852
15: Attach your brake ducting hose to the 'ring' you just installed on the back plate.
Attachment 322853
16: Install everything back and you just saved yourself over a 1100+ Euro/Dollars!!
It took me 3 hours, it helps allot! I drove my car hard after i installed it today and it works no more fading!! And when i park my car @ home i don't hear the brakes 'crack' or 'ping' any more.
It's like BMW left the space to install the ducting.
It's easy, Hope this post inspires you to put this cheap DIY upgrade on your M3 fast! Then you can finally drive it hard like you should!
Jr