From: jhormaechea [jhormaechea@netscapeonline.co.uk]
Sent: Wednesday, September 06, 2000 8:21 PM
To: 928
Subject: [928] Ceramic Brakes News


I have been in Spain for a short vacation and have been driving around
my shark (which has been sitting in Santander (Spain) for more than two
months). I bought a Spanish car mag. which publishes a very interesting
report on the new ceramic brake kit that Porsche will shortly make
available. It also tests the kit against a ceramic brake kit that
Mercedes will make available for the CL600 AMG. I do not know if other
magazines have published a similar test so I would like to share the
information with you. Let me point out some bits:

- The Porsche kit will initially be made available as optional equipment
for the new 911 Turbo on December 2000. On 2001 it will also be made
available as optional equipment for other Porsche models. The kit will
be for the four corners and will comprise discs and special calipers,
six piston for the front and four piston for the back. Disc diameter for
the front will be 350 mm. Thickness 34 mm. Calipers will be painted in
yellow so from then on, big reds will not be the top braking system at
Porsche. We will then refer to "Big Yellows". The discs will be
ventilated and cast drilled and their surface will have a rough finish,
according with the photographs.

- The discs are made of silicon ceramic mixed with carbon fiber. To
manufacture the discs Porsche mixes carbon fibers, a special resin and
carbon powder. With this mixture it fills special molds under pressure
which are then baked for some time at 1,000 C°. Then the disc is
machined and then mixed with liquid silicon and baked again at 1,500 C°.
The silicon reacts with the carbon to form the ceramic. It looks that
Porsche has achieved to master a method to avoid the carbon fibers from
participating in the chemical reaction between the silicon and the
carbon powder so the fibers provide structural strength without making
the disc fragile. There is then a final machining with tools of similar
strength to those used to work on diamonds. The resulting discs are very
light since their density is 2,2 grams per cm3 while the cast iron ones
are 7,1 grams per cm3. They do not rust, the friction coefficient is
greater than cast iron and the resistance to fade and wear are very high
and very low respectively. Porsche claims that the ceramic discs will
last 300,000 kms in normal road use which is about 7-8 times the average
duration of cast iron discs.

- The magazine has tested a 911 Turbo with the new brake system and a
911 Turbo with cast iron brakes (Big Reds) in a test track in Germany.
The test consisted of ten consecutive brakes from 240 Km/h to 0 Km/h.
The Big Reds must be great because it is not until the 7th brake in
which the ceramic brakes started making a difference and in the 10th
brake the deceleration of the ceramic brakes was 11.3 m/s2 compared to
11.0 m/s2 of the Big Reds, being the braking distance of 200.2 and 205.8
meters respectively. The differences where greater in the Mercedes
CL600. This means that in terms of braking distance and resistance to
fade the Big Reds are just great. A general comment of the test drivers
was the excellent braking feel of the ceramic brakes, the low amount of
pressure needed on the brake pedal and the surprising absence of any
trace of use on the surface of the discs after the test. As one of the
test drivers said, they were even cold!

- Price: According to the mag. the price of the ceramic option in the
911 Turbo will be 5,500 euros (about 4,900 USD).

Another relevant information provided about Porsche is that Porsche's
R+D division has achieved a record in patent registration and licensing
agreements with other car makers. Also the extraordinary demand for the
911 Turbo has made Porsche's board to decide to increase production for
up to 4,000 units per year instead of the 2,500 initially agreed. It
looks that things are going on great for Porsche!

Hope this info was interesting for you.

Juan

93 GTS 5spd