My calipers have been running hotter ever since I switched to DTC-70s up front. Even with titanium shims, I managed to cook my caliper boots last fall. So over the winter, I rebuilt both front calipers with hi-temp boots and seals from
OPS. Feedback from M3 owners seem to suggest these are up to the task, but with very little data out there, I figured it wouldn’t hurt to look into some cooling solutions.
On my old 3.0si, I installed
brake cooling ducts by the factory fog lights. For the M, I had to get a little more creative since I didn’t want to hack any of the factory plastics. My options were then limited to:
Option 1 - Illustrative Scoop off Control Arm
Option 2 - Illustrative Ducts in the Lower Tray
Even though less air is fed through with Option 2, I preferred its shorter and more direct path to the rotors. So I began tracing the factory tray on a 3mm aluminum composite sheet.
After trimming to shape, I cut out the inlet holes and attached the ducts with some low profile fasteners before sealing the edges with black silicone.
So how will the air be directed to the rotors? Simple… I picked up
Westerlund’s brake cooling kit. Install is straightforward. Remove the caliper, use tin snips to remove the dust shield. Use provided hardware to mount the new backing plates.
I have to say these things are absolutely beautiful. The backing plate bolts up to the spindle perfectly and provides the same coverage as the factory dust shields. Best of all, he was even able to customize the inlet to accept a smaller 2.5 inch hose.
The attention to detail is quite obvious. For example, he includes a C-shaped piece to cover the tiniest of exposed area on the hub that forms when you remove the factory pressed dust shield. Other features include a protective cap for the wheel sensor. Basically a Z4 kit offered by a Z4 enthusiast.