Running fast laps on Road America a 4.1 mile 14 turn road track. Are 3 long straights where speeds are in the low 140's that end in 90 degree or greater turns. Factory brakes do not hold up very long. The pads are gone in a 1 day session with rotors going perhaps 6,1 day sessions. Went to slotted rotors with hawk hp+ pads. Left rear rotor cracked in 2 places after a 2 day event. Pads ok. Replaced rotors with new set from 'Frozen Rotors' result left rear rotor cracked, both front rotors heavily heat checked. Pads ok. Any thoughts on what is going on and/or suggestions to fix? Thanks

 

With that much heat, you are going to get cracks. Buy some throw aways from Napa. About $25 a corner and they should last you a few events.

Good luck.

 

Rotors will crack from the heat of use. Most of the ppl that do track days or race the T1 vettes use the Raybestos Rotors from Rockauto or Napa. about $25 each - veryvery good rotors.

I have used the HP+ pad for one weekend of track time and found it to be adiquate, not great. It worked well on slower speed corners but on RA with those long straights and high speeds I would go to a more agressive pad like the PFC-01 or Wilwood "J" or "H" or the Carbotech XP-9 or XP10.

Yes these are racing pads and do not work well on the street so you would need to change pads for track days then back to street pads for normal use. Which this is not a bad idea as it does give you time to check your brakess, bleed and inspect before and after a day at the track.

Usually the rear rotors crack as someone will set the emergancy brake between sessions. This is not really a good idea as the heat from the brake pad keeps the rotor hot, yet the area of the rotor not touching the pad will cool down faster. These heat difference cause the rear rotors to crack.

An other thing you may concider is putting in some brake cooling ducts. The DRM cooling ducts with either the LG spindle ducts or the Phoenix Performce spindle ducts and or the home made mobil 1 brake ducts.

I have pics of my DRM & phoenix combination in my mods link below.

Good luck

Some day soon I hope to get back to Road America where I watched racing in the 60s growing up.

 

The rear rotors typically crack if you leave active handling on and run the car hard. Try leaving it off. Granted you lose your safety net, but you're much less likely to crack your rear rotors.

 

I've read a lot of these brake posts (and gotten yelled at on a few of them : ). AU N EGL makes good sense. Seems that no matter what, if you stress your brakes under track conditions, you're going to have to maintain them. There is no such thing as a brake that will hold up to that kind of stress without needing work. I used to think just buying some racing "big brakes" would solve all problems, but it seems like you need to get good at changing rotors (maybe between your street "bling" rotors and your track Raybestos units) and pads and fluid if you're going to seriously track your car. Does that make sense, AU N EGL?

 

There is one bad thing about tracking your car too much. When you drive on the street you cant track out to the left side of the road after you take a corner and THE BIG AND you cant roll your right foot to the floor as much.

So you just have to do more track days.

 

ThanKs for the help AU N EGL. Emergency brake never set after lapping for the reason you cited. Active handling/ traction control also off not in competion mode thought that might be the problem the first time around with rotors.

 

The C5/Z06 rear parking brake is a drum type brake that uses the center section of the rear rotor hub. It doesn't use the normal rear pads, so this really isn't an issue with our cars.

As AU N EGL said, I just use cheap stock rotors (get mine from NAPA at $25 a pop), with DRM ducts, SS lines, good fluid, and Carbotech XP10 front, XP9 rear on R-compound tires. I get about 3 track weekends out of a set of pads and rotors before I am uncomfortable using them in a race. Could probably use them longer in a DE which has shorter sessions.

I have also found that using Comp Mode greatly increases rear pad wear. In addition, the last time I cracked a rear rotor was after a DE where I was using Comp Mode. I raced all season not using Comp Mode and haven't cracked a rear rotor once. Note: I am not advocating turning off Comp Mode though. As I said, I even used Comp Mode in my last DE. Comp Mode is very good and you can go very fast with it on.

 

Over the last week and a half I have cracked two rear rotors. Last week it was the right side and today it was the left side. When I installed the rotors before last weeks DE I thought about throwing them away and it is evident I should have done so. They both had some small heat checks in them and had been used for 5 or 6 previous track days. One of them made it through one day at Watkins Glen and the other made it through 3 and a half days. I will never again install rotors that look like those two did when I started. When the one went last week I could feel the vibration and knew something was wrong with the car. However, today I did not feel a thing. I didn't know the rotor was cracked until I looked. Today the left rotor had one crack all the way through that you could see daylight through and about 90 degrees from that crack there was another one that had split just one side of the rotor. If it had failed on the track life might have suddenly become more interesting. I didn't bother buying a Lotto ticket on the way home since I think I used up all my luck for this week.
Bill

 

I feel bad for all the people that spent a ton of money on these high dollar brake systems, only to find out what the racers have been saying all along! If you take mass away, you retain heat!!
Cross drilled and slotted if for 'Bling Bling' not 'Race-ing'!!!

Ken