RonCT

Several of "the guys" at the track have started using Cayenne rotors on the fronts of their 996 GT3s. They are the correct size and a direct swap. The beauty is they are $235 a set for the fronts, are solid and so last 2x longer.

Anyone know of an OEM direct replacement rotor that will fit the front of a 997S?

$320 for a set of drilled OEM rotors isn't terrible, it's just a pain to have to monitor the growing cracks and then have to swap out when they start to connect.

Just did a little more research...

Looks like our 05-09 C2S have 330 x 34mm front rotors and 330 x 28mm rears. Various Cayenne rotors come in 330 x 32mm front and 330 x 28mm rear. So I'm guessing the rears are a direct fit, but any thoughts on using a 2mm narrower rotor on the front? As it is now with the 34mm, stuffing new brake pads in is a real chore (have to remove the dampeners). One rotor expert I spoke with thought using a 32mm would be fine on a 34mm setup, and another thought it wasn't a good idea.

Additional research - now I'm stumped...

From the Porsche website (of course nowhere official can I find full dimensions of the rotors):

The brake disc diameters are larger: 330 mm front and rear and the rear brake discs are 4 mm thicker – for even better braking performance.

That conflicts with the Porsche parts information that says otherwise. 34mm front is 6mm wider than the 28mm rear.

lawjdc

I would try Deman Motorsports - they make a beautiful slotted rotor that is very durable. No affilitation, just a satisfied customer.
http://www.demanmotorsport.com/

Derik Royal

Hey Ron,
I feel you pain. I just went through this exercise last week with my car. I have on 05 C2S with PCCB. I use oem 997 turbo steel rotors now.(350mm x?) When the ceramics discs let go, I had to use 997 GT3 steel rotors in a pinch, The fronts were offset 2 mm or so different then the turbo. It was a pain to get the pads/calipers on and it caused abnormal brake wear on the small piston end of the outboard pad. Once I switched back to the correct offset rotors I haven't had any issues. I was trying to verify if the Cayenne Turbo rotors are the same, but I couldn't get enough info to take the chance time wise. It seems the only way to know for sure is to have the two discs side by side for comparison. I never got that far this time around. Good luck. Please post what you find out.

adfsouth

I've talked to Deman......unfortunately they don't make rotors for the S, only the GT3....

Waiting to hear back from my dealer on the Chayenne ones.....

RonCT

I'm waiting to hear back as well and got one good opinion - that it appeared like they should work, but that the only way to find out for sure is to put 2 of the rotors next to each other and see.

Of course this would require a dealer having an S front rotor and a Cayenne 330x32 rotor in stock and be willing to take the time to compare them.

adfsouth

Just ordered a set from Suncoast to try next weekend. I've been told by a few sources that they should work just fine.

RonCT

Sweet - will be nice to know. Here's a thought on the rears - if the calipers are the same (Porsche is good for re-using calipers and rotors) on the Cayenne and 997S, then the rear pads should also match up part number wise. I have a feeling the rear isn't the question, but rather that 32mm front on a caliper / car designed for 34mm. As long as things line up (ie: rotor offset is the same), 1mm less material either left or right side of the center shouldn't be a big deal. Heck, 1 DE will lose you 1mm on each pad if not more.

Thanks for checking into it - let us know.

adfsouth

The only 4 possible concerns I was told about were:

1) Don't wear the pads down to the end as the 2mm in total rotor thickness could possibly cause the piston to come-out if you take the pads to the very bottom (change at 1-2 mm of pad).

2) The additional heat retained by the solid rotor could possibly cause the rotor to warp after extreme heat. I was told to roll the car forward a few inches in the paddoc a few minutes after parking following a session (I do this anyway).

3) Might need to top off the brake resevuar with a little fluid when you install due to the change in thickness.

4) Offset might change by 2mm (no big deal)

Other then that, should be good.....I'll let you'all know how it goes on the 4th at Sebring. Good Idea Ron!

Matt Romanowski

If you are really worried about the 2mm, have 1mm spacers made up for the back of the pads.

obsessedone

Will be interested in hearing how this goes.

I noticed this week that Frozen Rotors has added 997S frozen, slotted rotors for 997S to their website listing - another alternative. I was thinking of trying them. They are more expensive but I am tired of replacing OEM cracked rotors with plenty of thickness left. Has anyone used them?

RonCT

Typo on the frozen rotor site, they don't make slotted or solid for our 997s. They will be fixing the web site.

obsessedone

Bummer!

adfsouth

Installed the rotors last night and ran them for six 30-50 min sessions today at Sebring in 90 degree heat. I worked them hard all day with Pagid Yellows and they felt just as good as the original drilled ones.

Here are the detalis:

- Installation: A bit different as the solid rotors don't contain the 2 small screw holes found on the originals. The small screws used in these holes connect the rotor hat to the hub to facilitate caliper installation. They are also used for attaching wheel spacers....this means you can't use spacers with these rotors. There is one slightly larger hole where you can use one of the original screws to keep it the hat place......its not perfect but it works. You can also use a wheel bolt or wheel hangar to keep the rotor in place while screwing in the caliper bolts. Once they're on, they're on and the process for swapping pads and wheels are identical. Pad swapping is actually easier as there's an extra millimeter of space on each side of the caliper.

- Appearance: Diameter is exactly the same and they're just a hair thinner. The rotor hat differs a little in appearance but fits on perfectly and looks like it belongs. The solid discs blend in fine once they get a little wear/shine to them....however I must admit, looking at a Porsche with solid rotors is still a little strange to me. Regardless they're not very different looking then slotted ones. Of note, I believe the total offset moves in towards the car by 2mm but this really can't be noticed.

- Performance: The solid ones bed-in easier, heat up faster and stay hot longer after a session. They feel just as grippy and solid at the originals. They seem to be easier on the pads (no chunking). The SRF was fine and I didn't experience any abnormal brake fade. There were no signs of warping or hot-spots. At the end of the day, there were no cracked edges or surface stress marks of any kind.....just shiny, smooth solid rotors on a Porsche I'm thinking they will last much longer then the drilled ones.

For $235, this appears to be a great option. Kudos to RonCT for bringing this idea to life I'll post again after a few more DEs.

mobonic

sorry,

but if the heat up faster and stay hotter... how are they performing the same??

RonCT

Fantastic write-up! A couple of follow up questions:

1. Can you post the part numbers on the ones you used?
2. Can you snap a photo so we can see what they look like?
3. Any sign of pad material build-up on the rotors?

Thanks for trying this out! I know the 996 GT3 guys have had great success with a similar solid Cayenne rotor, so I had a sense that if there was a version that fit our 997s, this should work out nicely.