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I had these fitted to my S4 a week or two ago :
The big improvement so far has been the cars handling. They are 40% lighter than stock and the car is so much better for it.
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Valid point...but I have severe reservations about the use of multi-piece discs on road cars...many road cars are just not looked after well enough to ensure the rotors and hats remain free - assuming they are a floating disk?
The problem us northern types have is that the salt on the road will have them beauties seized solid in a matter of weeks...leading to additional brake problems.
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The air gap is twice the size of OEM and the venting vanes are scooped to grab more air.
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Or is it to throw more air out? /ubbthreads/images/graemlins/wink.gif
Generally, vented discs work better when being force fed air..something Audi bumpers don't do...so fitting HUGE vented discs will be relatively pointless unless you give them their own dedicated source of cooling air.
The design of the S3 bumper in particular was bad at cooling the front brakes.
Also, the Audi stone guard thingies on the inside do a rare job of keeping cooling air out and heat in - best they get binned ASAP...which again means more maintenance by way of inspections.
The best I have ever studied appear to be vented discs that are able to be force fed to their inner faces, (venting near the hub centre) which will allow the air to be thrown from the inner centre to the outside (near the wheel)..this seems to be the most efficient way to cool the disc...this also is the most efficient at keeping the balljoints and bearings cool.
The current design of big brakes under big wheels leaves little room for cooling air to be drawn in past the leading edge of the disc...all the more reason why owners MUST pay more attention to correct cooling from the inside.
The discs in the picture apear to be of this type...not surprising if they are based on / using a Porsche rotor!
Brakes eh? A science in themselves.