Kitc2246

Just replaced my Sebro slotted rotors on my 2013 Boxster S after 5 weekends. Get to try the FCPEuro warranty process next. Three weekends at Summit Point and a double at VIR. My son and I shared the car at VIR. Multiple cracks at the edge of the rotors to include several slightly larger cracks from the slots. All the cracks are on the outside of the rotor. Also running Raybestos ST-43 pads for the first time which amazingly still have approximately 1/3 left. More than enough for a two day DE weekend, but have another used set as backup.

Not an apples to apples comparison but ran drilled Zimmermans on my 09 Boxster. Replaced when the internal cracks started to join adjacent holes. Never had one crack to the edge. Surprised that the Sebro rotors have failed this soon before wearing out one set of pads. Understand the 2013 has 50 HP more and Hankook RS4s vs PS4S so brakes are working harder. Had run ATE 200 in the 09 Boxster for four years with no boiling issues. Boiled the ATE 200 in the 2013 Boxster S my second session at Summit. Luckily bought Motul 660 and changed at the track and only lost one session.

It appears that the Sebro slotted are retaining much more heat than the drilled Zimmermans which is causing the edge cracks. This extra heat obviously was a contributing factor to boiling the ATE 200. Have no issue with using the Motul.

I put the Sebro slotted on based on recommendations that they last longer than drilled rotors, but now not sure based on this limited experience. Assuming the FCP Euro warranty works not sure I want to run a set of drilled Zimmerman for a direct comparison.

Comments/thoughts

jscott82

IMHO Drilled have no place on the track. I would not even consider them..

Surprised the sebros are cracking so soon. I would look to rectify that rather than go back to drilled. I don't have experience with sebro or raubestos, so I'm no help there

jdistefa

Need better cooling.

Don't run cross-drilled rotors on the track.

/end

NightBlueTTS

FWIW- I tried the sebro slotted and found that they retained way too much heat. The fronts on my 981 CS were always smoking and I couldn’t keep wheel weights on the wheels. I have since swapped over to girodisc and have had no issues.

I wanted to like the sebros since they were so inexpensive, but didn’t work out for me. YMMV

also agree with others about not running cross drilled.

mhm993

Bigger brake scoops are a necessity.

NightBlueTTS

I believe the 981 already has them, no?

Viper pilot

I'll second the comments about GiroDisc's. NEVER had a problem with them on my '14 CS.

mgordon18

Can you send a picture of the Sebros with the cracking? I have them on my car as well and want to know what they look like when they need replacement. I got mine from FCP, too, so I'm looking forward to my next free set. Wondering how much return shipping might cost though!

991carreradriver

Before I switched to Giro's, I used the Sebro's on other 2 911 Carrera's. I found the same issue that you are describing. They are great street replacements and inexpensive, however they do not hold up to track temps. I was averaging three to four sets of Sebros for each track season (12-16 events), finally decided that my time and $$ were better spent on Giro's. Using RT RE10 pads, I have three seasons on my Giro's and will probably get one more. I believe after factoring my time wrenching and cost, they are more economically efficient than Sebro's.

Kitc2246

Thanks for the comments and advice. I can live with 5 weekends from the Sebro slotted especially if this FCPEuro warranty return works. I had just expected longer life from the slotted verses my experience with the drilled on the 09. Considering the initial COVID shutdown I'm happy to have something track related to complain about.

Pictures as requested. Sorry for the giant images.

Based on what I see about Girodiscs they are slightly larger than OEM and have a spacer for the caliper bolt. That means my Tarett brake studs are too short.

At VIR my son and I had several sessions that were back to back which may have attributed to the cracking. My last sessions were with TrackDaze at Summit which were 30 minutes X 4 a day.

I'm just doing DEs so the Girodiscs seem to be overkill not to mention the expense and replacing my Tarett studs.

Not to ask a troll question but why aren't drilled rotors good and safe enough for DEs? I routinely inspect pads and rotors during the day. With PCA we get a tech each morning. As stated in my OP I changed the drilled rotors on my 09 before the cracks joined and none at the edge. The slotted Sebros are more expensive and have not lasted any longer while IMO dump much more heat into the fluid. I could argue that the edge cracking on the Sebro slotted is more dangerous than the internal, not joined cracks on the drilled.

On a positive note the Raybestos ST43s are lasting much longer than DCT 60 on the 09. Also the Hankook RS4s are holding up well. Can see more wear on the left front outer edge, but nothing extreme. I had planned on flipping the tire for next Spring, but based on current wear and one more weekend that my be premature.

The 981 S have extra brake cooling compared to the 987.2. You can replace the "ducts" with 911 3.8 models (991) however they require the lower control arm or ball joint to be disconnected. Just had my adjustable lower control arms replaced so missed that opportunity. Was not expecting this issue with the slotted rotor cracks.

okie981

Any crack extending to or from the edge of the rotor is no bueno. Discard.

mgordon18

Thanks for the pics. Yup - those are donezo. Mine are not to that point yet, but still maybe worth replacing.

I don't know if FCP has some minimum wear threshold before they will allow warranty replacement.
FCP Euro@ - do you?

jscott82

Drilled are safe as long as you keep an eye on them. Your experience of drilled lasting longer than slotted is not normal. Drilled generally crack from hole to hole very quickly.

Never used sebros, but I wonder if the internal veining is off, if it's not moving air inside the disk, it will definitely overheat. So drilled disk with proper veining is probably better than slotted with crap ventilation.

Just a guess.
​

Mahler9th

So interesting to see some "new wave" perspective on "drilled" rotors. PAG ran them for decades as well as privateer teams running Porsches. Globally and with success. I ran them myself for a really long time.

What I usually say on this subject is "it depends."

I remember back in the 90's when I was running a 944 Turbo S that was a street/track car and sharing it with my wife. While back home in WI on a business trip I got to visit KMR, and we talked about braking systems. They advised a different factory proportioning valve and 965 rotors (with holes cast in)-- only 965 rotors from Porsche and not aftermarket. And we discussed ducting. I implemented some more advanced ducting. And we discussed pads, and they advised Pagid Orange. They has been running 944S2 cars in Firehawk, and were campaigning a 965 or two in IMSA alongside Rich M.'s very special 968. At the moment in time when I visited there, PAG was not running a factory team in the US.

Anyway, I always suggest folks think about brakes as a system, and to be wary of those that claim absolutes.

Certainly braking component and system designs and materials have evolved in the past 3 decades (since I started with this hobby) but two things I learned in year one (at my first PCA "meeting" in around 1988 where Bob Akin was the featured guest) still seem to be true: (i) be wary of absolute statements, and (ii) don't be afraid to get advice from experienced racing professionals.

We did not have the internet as a resource back then.

Quadcammer

My sebro slotted rotors last forever, but also try to stay off the brakes as much as poseible.

What are you doing about brake cooling?