[jyoung]

Hey all,

Just did my first track day this past weekend at TMP Cayuga (about 2hrs from Toronto, Ontario) and the G80 was a certified M-onster.

Only thing I wanted to raise though is that at the end of the day my rotors look like the attached image. Looks like a dark layer of pad material/brake dust covering only the surface area where the drill holes are. My only conceivable explanation is that the heat and brake dust that got caught in the drill holes combined caused this colouring. Any one else experience this or have any other thoughts?

For reference, TMP Cayuga is a pretty brake heavy track with several hard braking zones per lap, of which the hardest I did 195km/h down to about 80km/h.

Brakes feel fine and didn't experience any issues or noticeable fade though.

Cheers all

[Boomer 2019]

This is nothing more than brake pad dust and is perfectly normal. The pads wipe it away from the rotor surfaces as you are driving but it accumulates in the dimples. This is not a mechanical issue but a cosmetic one. As in how severe is your OCD. Washing will remove nearly all of it, but if the force is especially strong in you, then a toothbrush is called for. Personally, I don't even see it anymore. That's what track driving will do to you.

[TopJimmy]

The brake dust in the holes will fall out, or use a dry brush. The bluing on your rotors are the brakes “bedded in” which is proper. Leave that coating alone. If your brakes are bedded in and working well that coating helps the brakes work better.

[jyoung]

Thank you both for the insight! Gives me piece of mind! Got the itch to track this thing more now after the first one

[GrannyShiftG80]

cayuga is a very hard track on the brakes with the 2 back straights where you easily reach 180 + km/h

that's how my rotors look

keep in mind if you do track it more, consider track pads as the stock pads will wear out pretty quick, especially the rears will go first

there's no issues on the OEM braking system in terms of performance or fade though

[jritt@essex]

The blueish-gray color you're seeing is a layer of brake pad material that is now stuck to the face of your disc. With any new car, particularly before going on a racetrack, the brakes should be properly bedded/burnished. That means establishing a layer of pad material transfer on the brake disc face. Laying down a pad transfer layer prepares both your pads and discs for heavy use and can increase their longevity.

Also, NOT having a pad transfer layer on your discs is the leading cause of brake squeal. If the pads are running on a layer of raw iron disc, they tend to squeal, scrape, vibrate, and chirp. If the pads are running on a layer of pad material that has adhered to the disc face, they tend to run more quietly, the vibration is dampened, there is less squealing, scraping, etc.

What you really have to be careful of however, is overheating your stock pads. OEM pads aren't designed for heavy track use. If you overheat your pads, they will not apply an even layer of pad material on the discs. Instead, they will smear and splotch on the disc face in an uneven manner, creating high spots on the disc face. Those high spots collect even more pad material as the pads are heated and clamped on the discs, ultimately creating a vibration that is typically felt through the brake pedal and the steering wheel. Sometimes uneven pad deposits can be very difficult to remove, and sometimes they can even trash your brake discs.

Please see our Essex Parts learning center article, "Can I Run OEM Brake Pads on the Track?"

Please see the videos below. Sorry for the quality...we produced them a long time ago!

Finally, we have a patented machine that applies a pad transfer layer to discs prior to their first use on a car. We do this for professional race teams, as well as our AP Racing by Essex Brake Kit customers. It's called our disc burnishing service. You can see the obvious visual differences in pre vs. post burnished discs in the image below and in this video: https://www.essexparts.com/pro-race-...ng--burnishing