pete95zhn

Here's the data for 996 GT2 ( and GT3 too. I still suspect that there's a misprint concerning front disc diameter, IIRC it's still 350mm ).

4 Chassis and suspension 911 GT2
4 - 8 Service Information 2001

Brake system, general

The 911 GT2 is equipped with the new Porsche
Ceramic Composite Brake (PCCB) only.
The main advantages of the new system are:
• 50% reduction in rotating and unsprung
masses compared to conventional brake discs
with the same diameter (911 GT2 is 16.4 kg
lighter than 911 Turbo)
• Fast brake response
• Maximum fading stability owing to constant and
high friction coefficients
• Excellent responsiveness in wet conditions
• Long service life of brake components (brake
disc up to 300,000 km/185,000 miles)

Front brake

Brake disc

The front brake disc has a diameter of 360 mm
and is 34 mm wide. The brake discs have involute
internal ventilation and are perforated.
The brake discs are bolted to a separate stainlesssteel
carrier. The disc and carrier should, however,
never be separated. The vehicle type (GT or Turbo)
and the direction of rotation are indicated on the
carrier.

Note
The ceramic brake discs are sensitive to knocks
and impacts. The brake discs must never be
knocked (especially at the edges) when they are
mounted and detached. This also applies when
wheels are mounted.
Brake discs with chipped edges may still be used
provided that the damage does not exceed a
certain tolerance. Refer to the information give in
the Technical Manual.

Brake calliper

The tried-and-tested single-piece aluminium brake
calliper is also used for the 911 GT2 (the GT2
version, however, has six pistons).
The piston diameters vary according to the
direction in which the brake disc rotates through
the brake calliper. The piston diameters are
28/32/34 mm.
The brake calliper is painted yellow.

Brake pads

The brake pads are made of a special metal
composite material which ensures high and
constant friction coefficients when combined with
the ceramic brake disc, and has a long service life.
Two damping elements are attached to the carrier
plates. No other damping devices are necessary.
Brake pad wear is monitored.

Rear brake

Brake disc

The rear brake disc has a diameter of 350 mm and
is 28 mm wide. The brake discs have involute
internal ventilation and are perforated.
The brake discs are bolted to a separate carrier.
The disc and carrier should, however, never be
separated. An arrow on the carrier indicates the
direction of rotation.

Note
The ceramic brake discs are sensitive to knocks
and impacts. The brake discs must never be
knocked (especially at the edges) when they are
mounted and detached. This also applies when
wheels are mounted.
Brake discs with chipped edges may still be used
provided that the damage does not exceed a
certain tolerance. Refer to the information give in
the Technical Manual.

Brake calliper

The tried-and-tested single-piece aluminium brake
calliper is also used for the 911 GT2 (the GT2
version has four pistons).
The piston diameters vary according to the
direction in which the brake disc rotates through
the brake calliper. The piston diameters are
28/30 mm. The brake calliper is painted yellow.

Brake pads

The brake pads are made of a special metal
composite material which ensures high and
constant friction coefficients when combined with
the ceramic brake disc, and has a long service life.
Two damping elements are attached to the carrier
plates. No other damping devices are necessary.
Brake pad wear is monitored.

Brake unit and brake hydraulics

The diameter of the brake master cylinder is
25.4 mm. The boost factor of the vacuum brake
booster is 3.15.

And then a quote from 2004 GT3 Technical Manual:

PCCB (optional)
Right from production start, the 911 GT3 can be equipped with the Porsche
Ceramic Composite Brake (PCCB) as an option. This is the brake system which
is also installed in the 911 GT2.
Technical data
• 6-piston monobloc aluminium fixed callipers at front
• 4-piston monobloc aluminium fixed callipers at rear
• Brake callipers painted yellow
• Carbon-fibre-reinforced ceramic brake discs with evolute cooling channels, drilled
• Disc diameter 350 mm front and rear
• Disc thickness 34 mm f ront, 28 mm rear
• Brake pads specially adapted to ceramic brake discs
(front axle P 90-2, rear axle P 90-2 painted yellow)



So, would someone please make hats that have 996' dimensions but Brembo/Corvette bolt pattern?? Without Porsche Tax! All you need ( except 20mm spacers for rear calipers ) in addition to correct pads to make them work, if you just can cope with incorrect caliper colour...

EDIT. 380mm CCB's would be nice, but in my case it would mean changing 3 sets of wheels from 18" to 19". 350mm's preferred.

_rocket

If the thickness and annulus are the same (or near enough), stock Porsche caliper can be used.

Does anyone know the thickness of the zr1 rotors?????

Nizer

Awe come on, the ZR1 is a heck of a car and hell of a performance value. If they'd fix the interior I might even consider one.

mikymu

Thanks for the detail info and your brake mod. Very impressive. If push come to shove I may look into the ZR1 to GT3 RS brake mod but it will take alot of modifications including wheel selection to fit the gigantic rotors.

I know Dave zeckhausen well. Great guy and super helpful!

I left LA in 1993 after graduating from UCLA so I miss the flood. This past week has been nothing short of horrible as far as rain goes

prosper

Hi Mikymu

Wow, you study in UCLA,
although I study in USC,
My apartment was on Wilshire just 3 blocks from Westwood... We might actually met before, hahaha

anyway,

I have another info for you:
http://www.gmgracing.com/porsche_brakes.shtml

if you go to the most bottom part of the webpage above from GMG racing, you will see that GMG actually offer Brake Caliper Painting Service,...
so just in case you have to use the ZR1 caliper,
than you can let GMG paint it for you and change the logo into Porsche logo

below is what GMG say:

Brake Caliper Painting Service
GMG offers brake caliper painting service on used or new brake calipers. A very quick process which can be scheduled and done in one day. If your calipers are old and in need of some new life we can restore them to there original finish and quality. We can also paint calipers to any color you choose. Examples are Yellow, Silver, Black, Red, RS Orange and more. If you have a custom color in mind or are interested in color matching to your car this is also available. All calipers are available with the Porsche lettering in white, silver or black. We use a high temperature paint and special non yellowing clear coat.

All work done at GMG, mail order customers can ship there calipers in to have the work done. Turn around is just a few days and your calipers will be like new!

Please contact us for pricing.

mikymu

Custom CNC mill should be able to make the proper hat to fit ....

No idea ... I don't have a ZR1 rotor infront of me

You mean like this?

Nizer

Step in the right direction but IMHO the whole interior is a letdown relative to the rest of the car.

mikymu

Oh yeah, I used to live on Hilgard right next to UCLA sorority row ... those were the good old days. Thanks for the link. Caliper color don't bother me - they all become black any way

mikymu

Agree, If I get a Vette, the whole interior will be gutted for track. I will donate the interior bits to Budget rental for parts LOL

Atgani

Rather than trying to adapt the rotors and mounting bells from another vehicle, I suspect you'd be better off having a set of carbon discs made up to the original specs and sizes by these guys

http://www.surface-transforms.com/

They're available in sizes up to 410mm dia from Movit.
You'll find a brief explanation as to how they're manufactured here too.

http://www.movit.de/rahmen/ceramic.htm

And here's a few images of them fitted to my 996 GT2



Rear installation



Rear Disc



Front Disc

[/

As for the costs, the original PCCB rotors were expensive and time consuming to produce, The reliability issues experienced when they were first released were due to overheating issues. Subsequent refinements to the internal venting (and an increase in disc diameter) have improved the longevity of the products considerably.

They do have their limitations however. The wearing face is extrely thin, and once worn it can deteriorate and start to delaminate. This exposes the substrate the wearing faces are bonded to.
The substrate beneath has an incredibly coarse texture and is very hard, once exposed it wears through the friction linings in a matter of miles.

The ST discs however are formed using a different manufacturing process which means they're construction is homogenous. For the record, they're the suppliers to Koenigsegg.

They won't delaminate and if the surface should get damaged (by a trip into a gravel trap or a stone getting trapped between a wheel/caliper and the brake rotor) then the face can be reground and the rotor re-used)

As for the expense of the original PCCBs, when they were first announced Porsche AG were of the opinion they would last 120,000 miles.

I'll allow someone in the US to do the math, but how many sets of rotors and pads could a hard driven street car expect to use in 120,000 miles ?
Add in the labour to replace them for your average Porsche owner (ie one who lets his Porsche dealer fit them as opposed to DIY) and see what figure you come up with.

I drove my 996 GT2 with both the original Porsche steel 350mm discs and the ST carbons. The difference in unsprung weight is staggering and the difference in how the car behaves on bumpy roads had to be experienced to be believed.

With the heavy steel discs fitted to the car it was prone to understeer, the steering was heavy and responses through the wheel rim dulled.

With the carbon discs fitted the steering was lighter, less understeery and far more "pointy" and the front end was so much more planted over mid corner bumps.
Don't underestimate the benefits of carbon rotors for road use.

I've no affiliation with Movit or Surface Transforms btw

cfjan

How does the cost compare to the Porsche PCCB replacement disc?!

Looks like an interesting alternative. Thanks for the info!

Atgani

I purchased mine directly from ST some 3 or 4 years ago as they wanted a development car to trial fit the rotors to. This is no longer an option as the european rights to supply them have been secured by Guido at Movit.

I'm not sure if StopTech have similar intentions for the US. I suggest you drop Guido at Movit an Email for costs

mikymu

Very interesting and thanks for the link. I email Movit for pricing. Will give more feedback once I get an answer

MarekN

Atgani, just to be clear, you have carbon-ceramic rotors, right? Not carbons.

As for the weight of the things, I would love to know what your rotors weigh because from the look of it, they will weigh more than PCCB due to their construction. I would guess 7 kg?

I saw these rotors on a Z06 at Hockenheim last year and on that occasion they looked pretty thrashed with much deeper pitted areas than when PCCB´s go bad. I understand the argument that they can be resurfaced, but obviously at that time and on that car they had to be eating pads like a chainsaw.

mikymu

Movit is not a viable alternative for PCCB. I just got a reply back form them. You need to use their carbon ceramic rotor, caliper and pads and the whole thing cost more than $20K!!!