I installed brand new brembo discs and hawp HP+ pads on my FD. I didn't properly bed them in, I just drove normally for 4-5 days, then went to a track day. (I was invited the very morning so I didnt have time to do a proper bed in for the brakes)

the brakes made quite a lot of smoke after the first few runs, then they stopped smoking. I felt that the brakes had less braking power after the first few runs. Still enough to trigger ABS, but I had to press harder on the brake pedal

now after a few more days of normal driving, my rotors look like this. They still brake fine but the black/grey spots won't go away. Is this normal?

 

It looks like pad deposit. It's pretty common occurrence when the pads are overheated. Unless you are getting vibrations, don't sweat it, it will diminish with time.

The HP+ are great pads and I use them for street and autoX. However, I strongly suggest a more track worthy pad if you intend on doing more track days. The HP+ friction curve drops like a rock if you get them too hot resulting in a serious pucker moment. Did that exactly once...

 

Yup... overheated pads transferred material. Next track day you do, put some track pads like PFC 01, or even Hawk blue or DTC 70's, and they'll clean that crap right off.

 

pretty sure you can sand the pads and rotors and 'start over.' i think one of the brake companies has a writeup somewhere. wouldnt recommend doing any racing type activity with them like that tho.

break in is very important, esp with race(ish) pads. which includes HP+

 

You can always turn the rotors and start the break in period from scratch.

 

Use a Rotor Flexhone or Scotch Brite with brake cleaner to clean off disks and re-bed the pads in. Here is a good bedding procedure you can use.

If it happens again, maybe it is time for pads that are more suited for the application.

http://www.endlessdata.info/Endless%...d%20manual.pdf