Nordschleife wrote:
That is the theory, which is why quattro GmbH went that route. But look at how it as been applied in practice. there is no way any air can get into the rotors from the centre, the mounting method precludes that.
Ok. I'll admit that it has been a while since I was last grubbing around on my hands and knees puzzling over the intricacies of the standard front disc set up, but from what I remember of them it seemed as though there was plenty of room for air to be drawn into the intakes of the vents in order for them to work as they were designed to (perhaps someone would kindly post a close-up piccy of the standard disc mounted to the car at an angle to show the inner part of the veins and mounting pins (if possible)
).
When you say the mounting method precludes air to be drawn in, what part of the mounting are you talking about?? The pins? The wheel bolting on afterwards? You have me confused some what.
If anyone could be bothered to try (perhaps somebody already has
) I think you would be very suprised to see the results of a 'stand alone' bench test agaisnt the standard vented 370mm disc and it's pinned mounting hub 'Vs' The Movit/Brembo vented and drilled 380mm disc and it's solid bell, asking such questions like -
How much air can each disc displace (M3/HR) when spun at any given speed?
How long does it take them both to cool from a temp of (x) to a temp of (y) when spun at a speed of (z)? and what is the cooling rate across the width of the disc?
How long does it take them to reach a temp of (a) from room temp, when a braking force of (b) is applied against a loading force of (D)?
So on and so on until destruction...(oh yeah baby)
I can almost guarentee that in some areas the standard disc will out-perform the brembo. Like you rightly say ' the bits are ok, the intergration.........' seems to hit the nail squarely on the head.
As I see it (gavtheory), the venting on the standard disc is working exactly as it should be and will give a good even cooling effect across the entire width of the disc under 'normal' driving conditions for the car.
However, when pushed hard for longer than the intended design use (ie. track-days, bank robberies etc.etc.) the venting on its own simply can't keep up. Unlike the Movits, the standard disc sitting on pins has nowhere but the pad and fluid to put any excess heat that is built up once the ventings cooling capacity has been exceeded (ultimatley resulting in either pad fade or sponge brakes from boiled fluid depending on what pad material you are using).
The Movit brakes on the other hand are basically a set of race brakes for your road car and in their design clevely manage the extra heat build up better than the stanard kit through the alloy bell and wheel, only downside of this setup are the problems like what we have already discussed above when used on the daily trudge.
Something esle I have noticed (wether I am talking crap or not is something we can discuss), is that the internal venting is not what I would call consitant across the width of the disc due to the cross drilling going through the veins. Just like water, air will always want to take the easiest route to freedom after a force has been exerted on it, in this case some will undoutably be blown out through the drill holes, reducing the effeciency of the veins and possibly reducing the cooling effect from them at the edge of the disc. The veins on the brembo disc are only ever truly fully functional when they rotate passed a depressed brake pad and block the drill holes by doing so (i.e passing a constant flow of air through the centre of the disc from the inside to the outside).
It would actually be very interesting to get a smoke wand and move it in and around a spinning brembo disk to see the effect the drill holes have on the flow of air through the veining. (who knows, it may even be sucking air in through them??)
I'll shut up now hey...
Too much is bad.
Plenty is better.
) The Movit brakes while far better by design than the OE stuff( and the caliper certainly feels a good bit lighter than OE) fill my 18in std wheel even more than the stock parts, leaving even less room for brake cooling. The people I have spoken to reckon that the cars suffer far less from fade/overheating on 19in MTM wheels or similar, but the handling suffers/changes depending on your preferences.