I have a question about rotors...

After coming back from Daytona last weekend, I now have fractures running off all the holes in my rotors. Not severe and they don't go from hole to hole, or run to the edge of the rotor surface. I know it's not urgent that I replace them today, but it's time to at least order something to have on standby. It seems like there are a ton of options out there. I have no idea where to begin. I am probably doing 8-10 events a year now and use Pagid yellows. Pelican has three different brands alone (Sebro, Zimmerman, and OEM). Then there are a whole host of other folks that sells rotors as well. Lots of them for crazy $$$$. Suggestions on what to replace them with?

From my experience (with several 944's and a Boxster), the Zimmerman's are a good way to go. Less expensive than OEM, and I believe the only difference is the anti-rust coating on the hats. And possibly the drilling on OEM's may be chamfered on some models. For track duty, rotors are going to be replaced somewhat regularly (about 1 set per year to 2 with our cars). The radial cracking is a sign that the rotors are reaching the working limit. Changing at next pad replacement seems to work for me. Waiting till cracks are big and/or to the edge is not a good plan; seen some rotors shatter in the process. FWIW, I'm not sold on cryo products. I bought a set of cryo rotors for my 2500 Suburban from a company (Praise Dyno, in Texas) that makes outstanding brake pads for limited vehicles (including my Suburban). The rotors were badly warped within 2 months. Went back to OEM Chevy rotors and been working great ever since.

I'm not sure if I'm in the majority or not, but I think the factory front rotors and the Zimmermans are JUNK if you're using them for the track. They're fine for the street but you replace them WAY before they get near minimum thickness because of cracks between the holes developing. The rears seem to do a little better but still not what I'd suggest for that many track days in a year. The DeMann rotors are the way to go. It's a rotor that you'll actually get to use all the way to minimum thickness which will net you alot more track time. Well worth the extra money up front. Andy

I don't track as often but I replaced my OEM front rotors with DBA slotted rotors: http://www.tirerack.com/brakes/brake...ar=&perfCode=S $300 for a front pair, unfortunately they don't make them for the rears rotors.

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I googled demann rotors and came up with nothing. How do you find them?

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Those look pretty reasonable. Too bad they don't make a complete set.

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...probably because I can't spell. https://rennlist.com/forums/996-foru...ternative.html

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People go whole hog on upgrading their equipment such as new shocks and bars, springs, running shaved cup tires etc and then end up lowing their lap times to the point where they are entering braking zones at speeds where they generate WAY more heat then their OEM brakes were designed to handle. At what point will people figure out that they have to decide to s**t or get off the pot? Your either going to build a track car (and keep it on the track) or run within the limits of street OEM parts. I don't get the little bit pregnant part about modifications. Compromise is compromise. Changing rotors for handling heat on the track or throwing in different pad's WILL affect street performance. I guess if you drive more milage on the track then the street - it would be fine. But in my mind - if you want GT3RS speeds and still have a pretty good car that brakes at the first stop sign out of your driveway - buy a GT3RS! The factory spent a lot of time and $$ on development where the compromises are 'lessened' on their cars then what Joe Q Public would can up with by 'moding' up a generic 996 or 997.

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Even stock GT3 and GT3RS brakes aren't up to the task at the track. Track pads are a given for track use...and they're 45 min MAX to swap out for an event. The stock pads on my M3 are a perfect example. They fade after a few hard stops on the street and wouldn't make it 2 laps on the track before being a safety hazzard. Stock pads on the 996 were better but even on street tires after a few laps I'd have to back off to keep them cool. The drilled rotor design is more for show than for pure performance. Changing to slotted rotors is no different than changing sway bars. They make the car better at the track with no down side for the street. The rest of the system is up to par for 99% of us out there. A simple upgrade on the rotors and a pad change before an event makes for very little hassle in what is otherwise a great dual-use car.

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What tires are you running? You should try to match tires and pads. Too much brake and you'll be in ABS all the time. Too much tire (too sticky) and you'll eat pads and boil fluid. The type of rotor you get will be a function of cost vs. lifespan, although eventually heat dissipation may become an issue. As for rotors, I used OEM rotors for the longest time without any issues in terms of stopping performance on the track. However, they will not dissipate heat as quickly as a solid (dimpled/slotted) rotor. You can alleviate this with better cooling and higher temp fluid. Eventually I upgraded to PFC dimpled 2-piece rotors though. Zimmerman and OEM are virtually identical except for the non-rusting agent of the OEM. If you don't mind a little rust, save the money and get Zimmerman. [The rust is only cosmetic and does not affect performance]. The Porsche braking system is very robust, and I don't think you overwork it. And a couple cooling ducts fixes any heat issue. I know they ran 996s as Koni cars without any problems. And those cars ran full slicks and FAST laptimes. Changing rotors will have no effect on your street performance. And unless you have high temp racing pads, you will not have issues with those on the street either. New pads: $500. GT3RS $100,000+. Not even in the same ballpark. And the GT3 drivers immediately upgrade their pads, so now you're talking $100,500+. lol. I think your assessment is generally correct (i.e., get a track car) - but most people would rather driver their street car and enjoy it on the track rather than pour money into a car that has ZERO use outside the track. Upgrading your brakes and suspension to improve performance on the track doesn't diminish a car's other uses.

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My point is that people are expecting to do 10 laps in a row without any fade and are suprised when after two or three laps they find themselves in trouble or are shocked when they look at the rotors after a track day or two. Where the belief came from that they should be able to brake into every corner like they are Montoya lap after lap comes from, (TV or gaming?) but regardless that it is a Porsche, some fail to figure out it is still a street vehicle - not a race car. Putting on upgraded aftermarket pad's just delays the problems for a few further laps. Wearing out a set of pad's after ONE track day is crazy. That's a round about solution to the real issue that if your going that HARD on the track then you should really consider building a track car. I've seen guys in GT2's that blast around small tracks such as one in my area (Shannonville) that do not have long enough straights to cool the brakes off and wonder why everything is smoking and going south on them after half an hour on OEM brakes. They missed the physics lession in school I guess. W = J x Q. Wilwood's, Brembo's, Ap whatever aftermarket upgrade they put in to change this will not work in 40F temp's in stop and go traffic. The pad material for these types of brakes needs 4X times the operating temp's that street pad's do. Same with my home track - Mosport. Bolt in the Motron's, stiffen up and lower the car, braces all over the place, aftermarket billet whatever's under the car and then slap on shaved R compound's and out they go onto the track in a 3200lbs car. What are they learning by spending money getting rid of energy though heat all day??? Maybe if they spent a few dollars on driver training with a pro racer they would understand that you don't make time on a track creating heat (braking) you make time managing ENERGY. Just saying.

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After I got my old 996 properly setup with all the track goodies you are not in favor of, I could run 10-20 laps in 110 degree ambient [165 on the track] Texas heat on full slicks or R6s without any braking system issues. It IS possible. Even for a street car. It's all a function of proper setup. That being said, without the proper upgrades, the stock/hybrid system is not capable of turning lots of laps in extreme conditions. With aggressive pads without proper cooling you get this: -td

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Don't get me wrong - I'm not against all upgrades - just against upgrades that allow people to get in over their heads and going faster then their skill levels support. One should be wearing tires out on a track day - NOT brakes. If you can't drive home on the brakes you drove to the track with (allowing that they were in good shape to begin with) then you need to decide what your doing wrong OR that your nearing a point where a track car is a good idea instead of running the pants off an OEM car. And your right about car set up to a point, but from holding a CASC region licence way back in the 80's to observing the best and worst of people on race tracks for the last 25 years as a blue flagger/observer you see the same mistakes make day in and day out by 'lapping day' groups. Not PCA DE people per say, as generally they rise up through the PCA edu system learning from others as they go - but the 'arrive, pay the cash and thrash people'. I've learned more by going slow in a slow car (an old Sprite) with iffy brakes, no grip 70 profile tires then anything modern and going four times the speed. Thats a great video you linked to by the way. Here is one of my favorites: http://www.youtube.com/watch?v=n5rpFXdWtK4 Cheers.

Well, I just ordered and received my new Girodisk rotors from Craig at Rennstore. They are free floating, not cross drilled (so no cracking), and supposedly will last 2x long as OEM. Next time around new hats are only $300. I'll let you know how they feel after I put them on.

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Just an FYI - they are still going to crack. They all do. Solid or cross drilled. -td

I should probably give you a little more background on my car/driving to better assess this. The car is not a daily driver and gets minimal street time at this point. Like I said above, probably 8-10 DE's a year at this point. It's an 02 supercharged 996. I am running PSS9's, GT3 sways, MPSC tires, and some other stuff. As far as the brakes, I have the upgraded (slightly) ducts, SS lines, Motul fluid, and Pagid yellow pads. I have 35K miles on my rotors (they are orginal) and a bunch of track days. I was boiling the crap out of my fluid and burning up OEM pads until I switched to the yellows and the Motul. The SS lines and ducts were just for good measure. Now I drive to the track, run it all day, and drive it home. Pretty much with zero brake fade. I am very happy with my setup. As an aside, I have noticed no significant different driving with the yellows on the street than the stock OEM pads. Whether they're hot or cold. I think they're a great compromise between OEM and full race pads. Not to mention I have four or five track days and countless miles and they still look new. With that being said, is there a rotor out there that may offer an improvement (can't hurt) without spending a small fortune? Seems like there is definitely a point of diminishing returns when it comes to modding.

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I looked at those. Way too much $$$. At that price point, I'd rather just bite the bullet and go BBK.

Thanks for everyone's advice. I ended up buying Performance Friction front rotors and OEM rears. I'll be at Sebring in 2 weeks so I'll have a good opportunity to see how they perform.

UPDATE: I will now be carrying PFC rotor sets for the 996. Helluva lot better than OEM and a lot less $$$ than the other options. Begins with a low 8 for a full front set - arrives in about 5 days