Growliing noise x-drilled rotors

[quattrotman]

Hey guys,
Been a while since I've been here. Had a problem develop after installing B5S4 brakes up front. Mated them up with zimmermann x-drilled rotors and PBR delux pads. Everything has been great and stopping power is remarkable compared to the stock crap but lately I have developed a growling noise on hard braking. It is not a grinding metal on metal noise (plenty of pad and no groves on the rotors or visible damage). I took em off and they looked fine and no steering wheel shake either so I don't think we're talking about any warpage. So, has anyone else ever had this? It almost sounds like the holes are creating a cheese grater effect and that is the sound...the holes generating the noise as the go over the pad surface. Is this normal for x drilled rotors? I had them on my stock setup but they weren't nearly as big and they didn't make noise but I thought that maybe with the bigger size and added work these can do, that is where the noise is coming from. Any input from anyone else who has drilled rotors would be appreciated.
Thx.

[DenverNoob]

perfectly normal noise. cheese grater is about right...thats exactly what the rotors are doing to your pads...under hard braking they are scraping a smal amount of surface off and exposing fresh surface. keeps the pads from glazing over.

[jessefrank]

I have the Zimmerman x-drilled w/ Hawk HPS and I get a similar sound to what you described under hard braking.

I think Plain rotors would help eliminate/lessen the noise (like DenverNood stated) and also cut down on brake dust.
I love the way they look, but hate the extra dust associated with them.

[quattrotman]

The PBR delux pads that I'm using are surprisingly good and zero dust. I'm really happy with them. Thanx for the input guys, I was wondering if the noise was normal or not.

[nihil]

I get the same sound on my slotted rotors, it's normal.