Performance and longevity - I just don't know of anyone claiming more of either for less money.

 

I'm no expert - just looking to reduce unsprung weight. It seems that the 2 pc designs tend to be lighter.

 

Why do you believe this? My track gurus and Porsche technicians agree that

1) OEM cross drilled rotors are neither better in performance OR longevity. The holes heat crack and you will have to replace them LONG before they get to minimum thickness levels. They may be break-even in terms of cost effectiveness once you get past buying the 2-piece rotor hats, since you only new rotors which last WAAAYYY longer than OEM cross drilled.

2) As for performance, they may have more initial bite due to increased leading edge contact (which is speculative anyway), but overall, they have less surface area which means less braking "power."

3) Lastly, the light weight of OEM rotors makes them a terrible heat sink. Most 2 piece rotors, even with aluminum hats weight about the same as, or a bit more than OEM cross drilled.

I think you can verify this by looking at how many GrandAm or ALMS teams use cross drilled vs solid (slotted) rotors. Cross drilled may look neat, but they really serve no purpose on a track car. That being said, I still use them on the rear of my car, as there really isn't a viable alternative. Go figure...

-td

 

So this is the alternative I am considering - using slotted in the front, probably the DBA's (see the original link to tirerack I posted) and the OEM cross drilled in the rear. What do you think about this setup? Please state the pros and cons. Thanks.

 

There are no cons to this set up. Lots of cars use this setup, including GT2s and GT3s. I don't think you will have any problems with this setup, on the street or track.

The pros are better braking ability and cooler brakes. Although it appears that the DBAs are 1-piece, so when they need replacing you have to buy the whole setup again. With the Performance Friction 2-piece setup, you only have to buy the rotor and not the hat.

-td

 

Justed talked to Performance Friction. These guys only make dimpled for the 996, not slotted. Back to same point. BTW, P.F. sales rep told me that dimpled are only for clearing the out gases from the pad and do not help with cooling. And, more importantly, they cost $420 per rotor as compared to $133 for Porsche OEM. Other than saying that their rotors will last 3 times as long as the OEM's, the sales rep could not otherwise justify the price. I think I'll stick with OEM and replace the hat and rotor as one unit. Incidently, the rotor alone, from Precision, costs $248. Again, why not just buy the OEM at that cost.

 

For a number of reasons - virtually all of them track related:
1) OEM doesn't cool as well
2) OEM will heat crack out before they are used up
3) OEM holes will fill with brake dust
4) OEM doesn't have as much surface area
5) I'm sure something else track related

As for dimpled/slotted designs, they are not really for cooling. Well, neither are the holes in OEM for that matter. The designs are for evacuation of gases and moving brake dust. But with the latest technology brake pads, the gas evacuation issue isn't as big a deal anyway. As for the holes in OEM, there is some carry over to cooling, but only because the OEM are lighter and cannot absorb as much heat as solid rotors -> i.e, OEM are NOT cooler.

If you are JUST street driving, there are not alot of reasons to stray from OEM. If you are tracking, there are not alot of reasons to stay with OEM - well except the fact you don't have many other choices Hell, if you are street driving only, buy Zimmerman and save a few more bucks.

If you REALLY want to upgrade to slotted, try the 320mm or bigger slotted rotors and just get a caliper extension kit.

-td

 

I'm not disputing any of your points. All I said was that I have not seen anyone claim better performance or logevity for LESS money. It is a value statement, not bottom line performance. I have not had to replace my rotors yet, so am not that well versed in all the issues.

What front rotors are you using?

 

PFC 2-piece solid dimpled, 318mm.

-td

 

Me too with PF01 pads, noisy but great at the track. As many have stated, if you are only running on the street get OEM. If you do plan or are tracking the car there are other options out there. I was about to bite the bullet and buy a 355mm Brembo kit but was convinced by an instructor at a PCA event to buy the PF rotors with PF pads, swap to SRF fluid and be done. I was hesitant but opted to try it. WOW, did it make a difference. I was no longer getting any fade during numerous 30 minute runs and the pads have lasted over 5 events now with life left in them. Cost me $1500 for new pads for all four corners, rotors PF (f) and OEM (r), with new fluid. Costly, yeah, but at $3000 for a Brembo BBK going this route saved me a bundle. Is it better than a BBK, probably not, but good enough for my use.

3x better than stock for sure.

 

Well I guess that is my point. Since DBA's from tirerack are $158 for slotted, Porsche OEM's are $133, and Precision's are $430 for dimpled, it does not seem to make sense to buy the Precision's considering their price. I will concede that Precision is probably a better rotor, but $300 per rotor better? That's a hard step. On the other hand for not much more than the OEM, I can get DBA's and they are slotted. So unless those are poor performers, it seems like a good decision over OEM v Precision. IMHO.

I might eat my words sometime in the future. I do like the idea of a quality product like PF though.

 

td/himself has it RIGHT ON!

Eh just go with the 2 piece slotted for the 996, from the guy at Rennstore.com for $2200 front and rear or 1100 front?

340 mm front 320 rear?

A NO BRAINER if I had a 996 non-Turbo!

 

as the only stocking distributor of the Brembo rotors, I can let you know what is available. we helped Brembo in the release of these. shoot me a PM or email.

 

The ones I speak of are Girodisc, a hell of a lot less $$$$ than Brembo.

 

you get what you pay for... I would make a better initial investment to have a longer lasting rotor. The CNC machined hats are very nice on the GiroDisc. But the Coleman or Rotora rotor used depending on the application will not last nearly as long as the Brembo. As well, Brembo's McLaren hardware keeps the rotor in a true centerline for best braking and pad wear. Brembo's are not for everyone, but less $$$$ is something I would not want to risk as I am going 100 mph into a turn.