akediord

I went to MSR (Motorsport Ranch) yesterday with a local Z club. I've been out twice before and know the circuit. I've got what looks like some SERIOUS issues with my rotors. I only have vibrations in the high-speed, hard braking zones on the track. Driving home everything seemed fine. I was running the Panther XPs in the StopTechs and had two lead/follow sessions for the n00bs in which I brought the temps up nice and easy on the pads. After each session, I checked the rotors and had a nice, even application of compound. On the two hot lap sessions (20 min.), I started to get what looks like pad deposits on the rotors, with the second session being worse than the first.

This looks like deposition, right? The thing is, on the "splotchy" areas the rotor is actually scored as opposed to having a high spot of compound. You can feel this with your fingernail. These Carbotechs are supposed to be way track worthy and I just can't believe that I might have overdone them like this. I don't run a timer out there, but I do monitor my average lap speed. Back in June at a PCA event with this same compound I only hit a high of 47 MPH a.l.s. (WEAK!) and had no problems all weekend. Yesterday, I was booking it however and hit 53 mph in my first session and 64 mph in the second.

Can ABS kicking in do this to a pad?

<img src="http://www.waynewmedia.com/350z/images/rotor_deposits_02.jpg">
<img src="http://www.waynewmedia.com/350z/images/rotor_deposits_01.jpg">

Thanks!

nrh

The first step is always to disassemble and inspect everything. Check out the surface of your pads, are they consistent? If not, you probably cooked them.

Pick up a cheap disc brake caliper (the measuring device, not the car part) from your local auto-parts store and measure the scored areas and the non-scored.

I'm guessing that the scored areas are thicker.

p.s. I'm not a track superstar by any stretch of the imagination, but I've had my share of brake woes.

p.s. I'm not a track superstar by any means, but I've had my fare share of brake woes.
If so, I would suggest buying some real race pads (Hawk Blue works good for this), and throwing them on for a few hours at most. They'll clean your rotors off real nice if they're not up to temp. Keep an eye on them to make sure that you're not removing too much rotor material.

Then, next time you go to the track, swap your nice new bedded race pads in at the track. Our cars are hard on brakes as it is, I'm guessing the "street/track" pad wasn't up to the task.

I can't understand how ABS would do that to a rotor.

akediord

Here's the details on the Carbotech Panther XPs.

<i>CARBOTECH PANTHER XP (1108):
An extremely high torque brake compound with a wide operating temperature range (250F to 1350F). Unparalleled initial bite at race temperatures, high coefficient of friction (0.58-0.60), excellent modulation and release characteristics, extremely high fade resistance, very rotor friendly and excellent wear rates. Designed for race/track use with R-compound tires, but can be driven to and from the track if necessary. Not intended as an aggressive street pad.</i>

I really thought I'd be in the clear

juliem

that the pads overheated on the track and left material behind - I know you have good brakes cause I have them too

My car did this with porterfield track pads - I now run colbalt friction VR track pads and the above problem is gone

FYI I had this happen and then it got worse on the street and some other events to the point where the car was feeling undriveable! Solution? Put hawk blue pads on the car for a couple days and they cleaned that gunk off. This was at the suggestion of the stoptech folks FYI

I'm guessing this all on what you car looks like and my experience which seems similar. Of course, not seeing your brakes in person...

Warren Wang

XP's are good to 1200F. You baked the crap out of those. Heh. You'll have to turn the rotors on a lathe or run around for 2-3 days on Hawk Blues.

There are a few things you can do to prevent this. Use a compound rated (and tested) to work well at a higher temperature, like Cobalt VR's (shameless plug for my sponsor, but these pads really are incredible). Hawk HT-14's should do the trick as well.

Another thing you can do is to try and use less brakes. This one is tricky though. It requires that you have enough skill to carry the extra speed, or scrub it off with the tires. My lawyer would probably get very angry if he saw me suggesting this, so I'm not. This is a horrible thing to do. Never attempt it...

The biggest problem though is that you only got up to 63 mph. There's no chance for the brakes to cool off if you don't have at least 1 long straight. Even if you duct, with speeds that low, it's going to get REALLY hot.

Short tracks with lots of low speed braking zones are the hardest on brakes. CMP for instance. That track is REALLY rough on brakes.

Warren

nrh

In the catalog, hawk blues are listed as "easy on rotors" or somesuch foolishness. Your own personal experience is the only thing that really counts for a lot of this stuff, especially considering it's your life on the line in some of the scarier corners out there. Use what works for you. Your current pads aren't working

akediord

This was out at MSR yesterday. Did you ever hit that track before you left D/FW? 64 mph was my average lap speed. I was hitting 100+ on the longest two straights.

Here's pics of the pads. They look like polished marble. You can make out the reflection of the shop light, yellow color and all. I simply cannot believe I notched my performance up that much, but open track will do that to you. ;-) As I said, I went from an average lap speed of 47 in June to 64 yesterday. I used the pads in June no problem. I admittedly punished those brakes pushing as hard as I could. Looks like some custom duct work is next on the mod list.

Did I mention I did this on street tires? I guess I'm going to have to change pads at the track from now on and not try and find a streetable compound to get there on. I could just quit going to the track and save myself a lot of money. SURE! :-)

<img src="http://www.waynewmedia.com/350z/images/xps_02.jpg">
<img src="http://www.waynewmedia.com/350z/images/xps_01.jpg">

akediord

I guess I over did it and I was making sure to get off the brakes as quickly and smoothly as possible so I wouldn't ride them trailbraking into the corners.

The good thing is the pedal never got spongy and the pads didn't really fade. I could smell them, but they didn't go into green fade. I didn't melt my piston boots either. I'm running Valvoline SynPower and I'm switching to Motul 600 now!

Warren Wang

Reading is fundamental.

Err, at any rate, yeah, those things are Krispy Kreme glazed. Good luck bringing them back from the dead. They tend to re-glaze pretty easily once they are overheated, imo. Try coarse sandpaper.

Warren