I've used both Pagid Yellow RS19 and 29 compounds and that seems to be in line with the typical wear rate for these rotors. I would love to switch to non-drilled discs.

 

Or try PFC pads...

 

You call those cracks? Any rotor looks like that after a few laps no?
Drive the car cool longer, don't stop right coming off the track..

+1 on pfc pads.

 

They are.
CL pads?

 

Until recently, they were called "Carbone Lorraine". Now they are called "CL Brakes".

http://www.cl-brakes.com/en/

Scott

 

I bet disc wear rate is determined by input cost and metallurgy. Better chemistry, better wear.

http://www.shw.de/cms/en/business_segments/brake_discs/

 

I have to say the AP floaters I've had on the car for over 40 track days show no discernable wear at all.

Yes, the buy-in is high, but the payoff has already occured.

 

Subscribed in case someone has a source for 993 TT slotted front rotors. I have not found anything but factory drilled. I'd run those "cracked rotors" a while longer though. Mine show cracks early and stay like that for quite a while. As others have said, watch for cracks going hole to hole or to an edge (inside or outside)

 

I used the Powerslot Cryo rotors on my stock 964 with Hawk HPS pads. The rotors warped after 2 days on track.

-Reid

 

https://rennlist.com/forums/racing-a...ater-july.html

 

+1 - I finally tried these pads based on the too numerous to count () recommendations by VR. Love them, will not go back to Pagid.

 

You might try Chris Whaley / LC Motorsports for rotor options. He's a sponsor/poster here.

 

Giro disk




I still haven't found a source for the 993RS/tt slotted rear, it could easily be done, Giro disk has a 2 piece slotted rear option for the latter cars but not for ours

 

Looks like there are some good suggestions already. My experience has accumulated over 25 years, but alas I have never driven at places like the Glen. I have campaigned a big heavy street car.

What something is worth depends on what you compare it to.

With a heavier mostly-street car, I would always start with genuine Porsche factory rotors that come out of boxes so marked from dealers. I got this suggestion back in 1994 or so from the guys at Kelly Moss when they were the de facto factory race team. In their Firehawk cars they were using Pagid orange... not sure about the 965 cars. As I am sure folks here know, the factory rotors are cast with the holes, not drilled. I had good success following their advice, and stuck with it when I upgraded my 951 to big red calipers in front. For that application, I used 965 rotors. In my application and for my tracks, I would get cracking after a while. Rotors after all are disposables.

Jeff and David also suggested I work very hard to ensure the best possible air flow. In my application this meant augmenting the fiberglass backing plates of the Holbert Cool brake system so that the entire back side of the rotors was sealed off. In addition, I crafted ducting paths from the driving light openings. Finally I mounted some 911 a-arm brake air deflectors for even more cool air. All of these things helped make the rotors last longer. On that car, I used Pagid Oranges. I also tried Pagids black compound as well as several different PFC compounds. The Oranges were the best for my needs.

I have never heard that cracks be encouraged from overcooling/thermal shock in a scenario where the rotors can cool off too much on a part of a lap. Not saying that cannot happen, but I have never heard that before.

I have never heard that any types of cryo treated rotors are effective.

If I were ever going to try slotted rotors, I would want pieces with the highest possible engineering specifications... at least as good as what Porsche specs.

I have never heard that making alternative choices amongst the many choices of racing pads/compounds can help discourage cracks. Sure, folks talk about rotor life being better or worse with different types of pads, and I am sure some people have actually made careful experiments counting laps and measuring wear. But crack creation and growth may be a different animal.

I consider rotors disposables like everyone else. I do not think the factory parts are crap.

I prefer to find people with tested approaches running my tracks with cars very similar to mine to get ideas from brake system changes. Best if they hve professional racing experience. My approach works better off line than on the internet.

When I moved from my 3000 pound, 360 bhp 951 to my 1950 pound 360 bhp 911, my rotor costs went down. Way down.

 

Lots of wisdom right there from Mahler9th,................

We do use real racing rotors (AP or Alcon) for high-stress applications since they are far more durable and the payoff is in the long run.

Dealer-sourced rotors are really better quality than OEM (Zimmerman, Sebro) equivalents.

993's with stock brakes really put the heat into the rotors due to the car's mass, especially on DOT race tires. You should find out your peak rotor temps using temperature paints so you know what you are up against. In many cases, we use different pads on the rear to change the bias and this transfers some of the excessive heat load off the fronts at the same time.