[Hex]

What are the pie tin looking shields for on the inside of my front rotors on my M4 CSL?

[Hit_Apex]

Originally Posted by Hex

What are the pie tin looking shields for on the inside of my front rotors on my M4 CSL?

Dust shields - common on most disc brakes.

[bri1042]

Originally Posted by Hit_Apex

Dust shields - common on most disc brakes.

Plus, every once in a while, if you've been nice to your brakes, they'll give pie.

[Hex]

They sure look like they will retain heat.

[Hit_Apex]

Originally Posted by Hex

They sure look like they will retain heat.

The purpose is primarily to protect inboard suspension bits from heat (rubber bushings) and caustic brake dust. But, you are right they do limit rotor cooling. Race shields typically have a port (2-3" cutout) in which to route ducting to an inlet at the front of the car. Not really an issue unless you are endurance racing.

[Stockholmarn]

That's the pebble resonator. You'll notice is has a built in alert function if you ever get a small rock trapped against the rotor.