From the DBA website.....

[Q]

I found this on the "Oddball Facts & Figures" page

The 1996 Lotus Elise roadster became the first road car to use aluminium disc rotors. These rotors (which uses silicon carbide reinforcement) weigh about half as much as cast-iron equivalents and boast better thermal conductivity. The major down side is the high cost. In Australia, a joint research project between Disc Brakes Australia and Cyco Systems Group is investigating using a cheaper and more durable aluminium-ceramic composite rotor for normal road cars.

Sounds interesting !
Can you give us a more thorough run down on this technology !
and what we can expect in the marketplace in the future

[dbasteve]

Originally posted by Q
I found this on the "Oddball Facts & Figures" page



Sounds interesting !
Can you give us a more thorough run down on this technology !
and what we can expect in the marketplace in the future

IT... DOESN'T WORK..!!....

[dbasteve]

Seriously now...

The company that made these discs for Lotus has closed down. The Lotus Aluminium rotor project was scrapped and they went back to cast Iron discs. I do hear of Universities ECT working on whats called MMC's which are composite alloys but have not seen any viable results.
Brembo are making a disc rotor for the RS4 Audi which has an Aluminium centre cast into a cast iron disc. I have not enquired about the cost of these discs yet but i expect $$$$$$$$$.
Another sucessful product is the Ceramic disc that is available as an upgrade option for the new Porsche and some Mercs. This involves an ultra light ceramic disc with ceramic pads that are guaranteed for life. For $15000 you can afford to offer these guarantees.
The most popular weight reduced product now is the Two Piece disc rotor. It has a cast iron braking ring with an Aluminium hat bolted on.

[Shifty]

Don't quote me on this.. but I thought cast iron was prone to cracking with any kind of impact?

[dbasteve]

Originally posted by Shifty
Don't quote me on this.. but I thought cast iron was prone to cracking with any kind of impact?

Not any kind!
The kind that would break a wheel or axle definetly would break a disc and thats what you would have to do to get to the disc.

[AzzurrA]

dbasteve.... i noticed on the dba site the new 'kangaroo paw' design... could you give a brief description and give your honest opinion to the usefulness of it? Does it actually ait in the cooling, or is it just a gimmick?

[Jim]

Torana fan, if it makes a significant difference to heat dispersal then it is by definition not a gimmick. Their website has good tech info to back it up


**********

A friend ran a two piece disc with the alloy centre on his Lancer street sedan club racer, and the bolts securing the alloy hub to the disc came loose repeatedly, and eventually sheared off in spectacular fashion.

Is there some sort of preventative maintenance required on these things? Do they come loose periodically as part of their normal life? Is this a common problem with these, or was this one a one-off incident?

I am bearing in mind that this guy is a bodgey bugger and probably did it up with a 10mm k-mart spanner with no loctite...

And of course, the real question, does DBA stock them, and for which models?

[TheNewMonaro]

Secoh-
I thinkj they make them for a few cars.. WRX comes to mind, alloy hub with cast iron rotor. That photo above is of these I believe.

Hubs come in 3 different colours, don't know what they signify.

[dbasteve]

Heat is the major cause of disc brake related problems.

This Kangaroo Paw pillar design was developed to reduce disc distortion under heat load which can result in one type of DTV ( Disc Thickness Variation ). This is commonly known as shudder, pedal pulsation, or warpage.

The pillars are designed to overlap one another to work like a pump impellor forcing cooler air through the centre of the disc. This can reduce operating temperatures by about 100 deg C.

The other fuction is to reduce distortion by using the 144 staggered pillars. This will pin the two rotor faces together and reduce the swelling that occurs under heat load.

We have had this design independantly tested by consultant Automotive Engineers as well as our own testing on the road and track. To qualify for patent rights in the Automotive industry the design must be unique and credible.

The Kangaroo Paw wont solve world peace but it does work.

[dbasteve]

Originally posted by Secoh
Torana fan, if it makes a significant difference to heat dispersal then it is by definition not a gimmick. Their website has good tech info to back it up


**********

A friend ran a two piece disc with the alloy centre on his Lancer street sedan club racer, and the bolts securing the alloy hub to the disc came loose repeatedly, and eventually sheared off in spectacular fashion.

Is there some sort of preventative maintenance required on these things? Do they come loose periodically as part of their normal life? Is this a common problem with these, or was this one a one-off incident?

I am bearing in mind that this guy is a bodgey bugger and probably did it up with a 10mm k-mart spanner with no loctite...

And of course, the real question, does DBA stock them, and for which models?

We make two piece rotors for the WRX and are expanding the range slowly. This has been a very successful design and we are very excited about the introduction of this type of product. What we don't want to do is rush in with a half baked solution for every model car available.
We have been making the flat rotors used in these two peice discs for quite a few years. These discs are exported to the U.S.A for Corvette, Mustang, Camero ect upgrades.

By late this year we expect to have a Skyline GTR, STi WRX, and Turbo Supra solution for the market.

Secoh,
Your friend is probably using niloc nuts which melt at 350 C and fall off.
He should be using Conlok crimp nuts which cannot vibrate loose. These bolts should be torqued to the correct setting as well.