Hard life for Power Slot slotted rotors

[CB72]

My 97-05 rear brake rotors have reached their end of life following a couple of years of hard use.
My setup uses the larger 97-05 rotors in conjunction with 4 pot AP Racing calipers in order to provide the right balance with my front Porsche calipers.
The latest pads were the Pagid RS 14's that can accept very high temperatures.
I believe that what maybe killed the rotors came from the fact that the wheel nuts were not properly tightened when I had my tires changed...
The heat had no way to go except to damage the disks.

 

[Stephen@NCAutoUSA]

Looks like what happened with my Wp pro rotors after a few track sessions at Vir in July. However I had drilled rotors and no vents set up so that was likely a contributing factor.

 

[LuckyM]

Damn, sorry to see that. What brand are your rotors? I'm looking to upgrade my rear to 97 up rotors soon.

 

[CB72]

Looks like what happened with my Wp pro rotors after a few track sessions at Vir in July. However I had drilled rotors and no vents set up so that was likely a contributing factor.

The drilled rotors will show cracks that originate from the drillings after only a few hard laps.
I've been told that it's not an issue unless it happens on the outer holes?
I check mine after every track day.

- - - Updated - - -

Damn, sorry to see that. What brand are your rotors? I'm looking to upgrade my rear to 97 up rotors soon.

I got them from ScienceofSpeed but I believe they come from Centric?

 

[asylum]

All my stock size disc ended like this with XP10 pads after 3 or 4 trackdays. And after 5 or 6 trackdays, at least one of them cracked. No miracle with the stock size. they worked great without fadding. But not that long.

 

[Stephen@NCAutoUSA]

Yeah I've been told that too. When the spider webbing hits a certain length then it's time for replacement.

 

[docjohn]

rule of thumb:wink:......if your fingernail catches the cracks time to replace.

 

[jaffaz32]

Isn't Cryo treating rotors meant to help?

Centric offer this.

 

[CB72]

Isn't Cryo treating rotors meant to help?

Centric offer this.

I suppose it should?
A better solution could be to build a 2 piece rotor with an aluminium bell?
AP Racing has a range of 304 mm disks that are 25.4 mm thick.
I don't know if they would fit a later OEM caliper but I believe they would fit my 4 piston calipers.
Here's their range: http://www.apracing.com/products/race_car/brake_discs/ventilated_discs/ø304mm/25.4mm_thickness.aspx
At first sight the bell could be almost flat making it very easy to produce.
I'll investigate further.

 

[nsxtasy]

rule of thumb:wink:......if your fingernail catches the cracks time to replace.

Don't try this when the rotors are hot when you come off the track. But John's correct. For a visual check, I found that rule of thumb was also about when the individual cracks reached a length of 1/2". Note that those cracks fill in when the rotors get hot out on the track, and spread open as they cool down. So it was not uncommon to find that the rotors felt okay on the track, but after cooling down for the ride home, you could feel and hear them every time you braked.

I've gone through a lot of rotors (which you tend to do when you put 13,000+ actual track miles on your car). I've used them all - solid-faced, slotted, and cross-drilled. They all lasted about the same amount of time, around 800-1400 actual track miles. Despite people claiming otherwise, my cross-drilled lasted just as long as the others.

The only type I used that consistently lasted longer were two-piece rotors (in which the outer ring was a separate piece from the inner "hat", using flexible connecting hardware). They lasted about 50 percent more track miles, but they also cost almost three times as much.

And all of this usage was with front rotors. In all those track miles, my rear NSX rotors never developed any cracks. I think I replaced them once, maybe twice, because they were starting to approach the minimum thickness spec.

 

[CB72]

I just replaced the rotors today and here's what the rear RH rotor looks like...
Thermal shock I suppose?
I'm glad it didn't break apart at the end of the 130mph straight!

 

[chudson1549]

wow