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Discussion Starter #1 (Edited)
I had a thorough tech inspection done a week before the track event. The tech said I had some surface cracks that looked a little dicey. They hadn't made it all the way to the edge of the rotor. But they were "worth keeping an eye on." Everything looked fine at the end of the first day. But come morning as I was driving through the paddock something didn't feel right. Apparently cracks like this usually form over night when the rotors cool down completely.

Nearly the whole paddock came by to see the rotors. Half of the people had a story about a rotor like this letting go completely and causing a serious wreck.
 

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Discussion Starter #5

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I guess the heat cycling caught up with them. Glad you caught it before you went on track, that could have been ugly otherwise.
 

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yes tell of their glory stories of war and mayhem
 

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Who manufactured those rotors please?
 

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this is why it is a complete waste of money to buy slotted and drill or even just drilled or just slotted rotors... Factory rotors can hold up to abuse!

These cars need pads, SS lines, and fluid. the rest is a waste of money!
If you notice the damage wasn't even near the slotting. This is know to be an issue with cross drilled not really slotted.

Sent from another garage.
 

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@grindMARC - what pads were you running? So, glad you caught this before the 2nd day running started and the fact you were cruising around the paddock! I dont even want to imagine this on a live track! Godspeed to you!

On a separate note - Do you think this will occur more frequently if you dont match up the rotors to the pads? e.g. running aggressive pads + running normal rotors
 

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Heat is the culprit here. Did you have front scoops installed?. You can run the OEM system to a certain performance point but as one progresses on the track your confidence in the OEM system begins to erode. Moving to one of the available aftermarket systems highlights the short comings in the OEM systems and one will gain improved track times with the investment. Either the ESSEX or Willwood systems provided through Todd are excellent and both provide enormous amounts of information on brakes.
I experienced 200 degree drops in rotor temperatures with just ducting. This improved the longevity of my solid OEM disks substantially. I recently switched to one of the aforementioned performance systems and with the ducting i have a tough time reaching temperatures to bed the brakes legally ( you get the point) prior to track days. This was never a problem with the OEM system. Tracking experience is similar in that i have no concerns with the braking system and have found them to run cooler with much improved cool down. Pad selection is still an integral part of braking longevity and effectiveness. I believe that two part rotors will alleviate some of the issues that were experienced here also. I would suggest your driving level has exceeded the OEM system and it is time to consider an upgrade.
 

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Discussion Starter #18
@grindMARC - what pads were you running? So, glad you caught this before the 2nd day running started and the fact you were cruising around the paddock! I dont even want to imagine this on a live track! Godspeed to you!

On a separate note - Do you think this will occur more frequently if you dont match up the rotors to the pads? e.g. running aggressive pads + running normal rotors
The last three sets of race pads I've used were the DTC-70s. Remember, I'm running 6-piston Wilwoods. So, YMMV. I think the issue has much more to do with my tendency to overcook my brakes. If you keep them temps in check, I think most rotors will do fine. I spent a session with the RTR head instructor and he helped me with some major improvements to my braking. So, I'm hoping that I'll be able to stop buying brake fluid in bulk from here on out.
 

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Discussion Starter #19
Heat is the culprit here. Did you have front scoops installed?. You can run the OEM system to a certain performance point but as one progresses on the track your confidence in the OEM system begins to erode. Moving to one of the available aftermarket systems highlights the short comings in the OEM systems and one will gain improved track times with the investment. Either the ESSEX or Willwood systems provided through Todd are excellent and both provide enormous amounts of information on brakes.
I experienced 200 degree drops in rotor temperatures with just ducting. This improved the longevity of my solid OEM disks substantially. I recently switched to one of the aforementioned performance systems and with the ducting i have a tough time reaching temperatures to bed the brakes legally ( you get the point) prior to track days. This was never a problem with the OEM system. Tracking experience is similar in that i have no concerns with the braking system and have found them to run cooler with much improved cool down. Pad selection is still an integral part of braking longevity and effectiveness. I believe that two part rotors will alleviate some of the issues that were experienced here also. I would suggest your driving level has exceeded the OEM system and it is time to consider an upgrade.
I'm running 6-piston Wilwoods with Mike's guides. I'm planning to add VT's stage 2 ducts this winter though.
 

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Heat is the culprit here. Did you have front scoops installed?. You can run the OEM system to a certain performance point but as one progresses on the track your confidence in the OEM system begins to erode. Moving to one of the available aftermarket systems highlights the short comings in the OEM systems and one will gain improved track times with the investment. Either the ESSEX or Willwood systems provided through Todd are excellent and both provide enormous amounts of information on brakes.
I experienced 200 degree drops in rotor temperatures with just ducting. This improved the longevity of my solid OEM disks substantially. I recently switched to one of the aforementioned performance systems and with the ducting i have a tough time reaching temperatures to bed the brakes legally ( you get the point) prior to track days. This was never a problem with the OEM system. Tracking experience is similar in that i have no concerns with the braking system and have found them to run cooler with much improved cool down. Pad selection is still an integral part of braking longevity and effectiveness. I believe that two part rotors will alleviate some of the issues that were experienced here also. I would suggest your driving level has exceeded the OEM system and it is time to consider an upgrade.
Actually it's far more common for brakes to crack that have too GOOD of a cooling solution. The temp variance is what kills rotors. My Time Trial car doesn't even have any form of brake cooling. Neither does the focus, which I have tracked a few times without rotor issues.
 
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