Hi,
I made a trackday with an hard braking point (from 195 km/h to 60 km/h, more or less). Pad and Rotor where bedded on street and used for the first time for track on this event (both new). Braking feeling was always good. When yesterday I have a look at my disk and pad I noticed that:

Ant Rotors as you see in the pics have material in the internal surface but less the external part, why?

Only the internal ant pad lost part of its material on the edge, why? Is there a way to prevent this problem?


My idea is that the stock cilinder doesn't work properly under hard braking, I don't know if for temperature but pressure on the pad seems (looking at the rotor too) not to be uniform on pad'surface, but higher on the internal edge (towards the centre of the hob) rather the external.



Thanks

 

What brand/type brake pad were you using?

 

You're overheating the pad.

What pad is this?

 

Dixcel pads and rotors.
What should I do to prevent overheating? How could notice it while driving?

 

Which model of Dixcel pads are you using?

http://www.dixcel.co.jp/en/pad/

They make a "street pad" that will not have the heat resistance that a race pad will.

S2000 pads are kind of small and generate a lot of heat over a small contact area. You need a pad that will have higher heat resistance.

For example, the difference between a mild pad and a full race pad can be as much as 500 degrees C in resistance.

http://www.ctbrakes.com/brake-compounds.asp

When a pad can't handle the heat, it chunks.

Are both your fronts like this? Because a sticky caliper or brake pad tab ears could cause a similar issue.

Also, possible that the street bedding wasn't aggressive enough to cure the pad.

Just throwing possible causes out there.

It would really help if you were as complete as possible with your information including:

1. What MODEL of the Dixcel pad?
2. Do both pads in that corner look the same?
3. What about the opposite side?
4. What tire compound are you using?
5. Do you have aftermarket brake ducts?
6. Have you been to track days before in this car? What are the other pads you have used?

 

Here you have the track,
http://www.youtube.com/watch?v=iwzB-Y11Cl4
from minute 2.09 after a long straight, you see the hardest braking point, followed by a sequence of slow bends. This is an old video, with traffic and old setting:
- Rotors: stock
- Pads: stock
- oil: castrol srf
- hose: goodridge stainless steel hose
- Tyre: A048 215/45 and 245/40 on stock wheel (very very old, 3 year, as you can see in the video I had no traction)

Actual (and final I hoped) setting (relative to the photo in the post):
- Rotors: FCR dixcel ant/rear
- Pads: R01 (ready RA in my box for the future) ant/rear
- oil: motul RBF600
- hose: goodridge stainless steel hose
- Tyre: AD08 215/45 and 245/40 on stock wheel

from that video to my last session:
- -3/4 sec... best at 1.47.7 (regular 1.48.4) against old 1.51
- braking at 100m more or less against old 150m
- no fading
- no braking problem, just a sensible increase in the pedal run (sorry for my english), before starting braking... but it didn't compromise my braking distance and deceleration.

About your questions:
1. read up
2. no, only internal ant right, external ant right pad is in good condition with the edge like the one of the internal in the upper part (as soon as possibly, I'll make a photo)
3. external left side is ok like the external right. Internal has an hedge similar to the internal right, in the upper part has small wear and tear, in the lower side is like the left lower side of the pad in the photo, if you notice it is deteriorated but not crumbled.
4. read up
5. no
6. of course since year, taking part to trackday event too. Stock (on stock rotor), EBC Yellow on EBC slotted (terrible), Ferodo DS2500 on stock rotor. I changed stock rotor ant/post with EBC (cracked), back to stock, now dixcel (ant/post).

About street bedding. When I did it for the first time, I saw smoke from brakes (rotor and pads where both new which is normal when bedding racing pads. Then I drove the car on the street with occasionaly aggressive montain driving, for almost 3 month... so I suppose that bedding was ok, but here I'm... some mistake was made.

Just to add another point. Before track event, on regular street use, my brake whistled a lot. Now they don't... it seem to me that after few days they are starting whistling again, but at very low speed and with a slightly pressure on brake pedal.

 

I don't know if this link will help. This is #2 in a series of three video and text discussions on brakes.



http://www.essexparts.com/learning-c.../swapping_pads


See also

http://www.essexparts.com/learning-c...ose-brake-pads

 

every help is well accepted. Thanks

 

It just appears as if those pads cannot handle the heat. That track doesn't appear to have a lot of heavy braking, but more of a lack of cooling zones for the brakes. There only seems to be one straight where they have time to cool which unfortunately ends with heavy braking. I'm not sure what you can get in your area, but I would recommend trying out some higher performing pads or consider some ducting.

 

Had the same issue with my Ferodo DS 1.11 which are supposedly used for rallying. Tried second set and it was the same even with my extensive brake ducting. It's scary because those chunks breaking off can get stuck in your caliper and screw up your braking. Chucked them and now use Project Mu 999 which seem to be delivering the goods. Was highly recommended by a forum member who uses it on his own car and got a good deal thru him for them.