well i'v been told that Sline calliper carrier are 146/7mm from one bolt hole to the other, which seems to be the same as the carriers on the Audi 3.2fsi.
But best bet if there not Audi brakes that you fitting is to ask Brembo.
Unfortunately after searching the forum myself I didn’t find too much. I know that the Quattro brakes are slightly larger then non Quattro models. The V8 A6 uses an even larger disc on the front and I’m pretty sure larger rear disc too.
I’ve wctually got the V8 front disc(350mm) fitted under the 6piston callipers from a Touareg on the front of my A6. I’ve not got round to upgrading the rear yet but some V8 or S6 rears are what I’ll be fitting.
Here’s a pic of mine fitted. Not the best pic but you get the idea.
Hi I am currently running the Audi A8 D3 360 mm frount setup on my A6 C6 Avant, this is a really nice setup for fast Road use, it is basically a strait swop apart from the solid brake hose which will require shortening and the brake line/wire carrier which required a modification, but it’s easy enough to do.
Try searching for.
Audi A8 D3 V6 V8 Front Caliper For 360X34mm Discs 4E0615123
The Calipers are a sliding twin pot design, the pads are huge compared to a standard setup, its a bargain for a very good upgrade, and some of the best brakes I have fitted to a road car.
If your are after a track setup that can get expensive quickly.
Calipers and carriers need to be replaced these are a straight swap. Minimum wheel size is 18 inch.
Here is a picture of my new Red Stuff pads vs the original pad from the 345mm disk set as supplied on my car, as You can see they are a huge pad, even though I have only increased the disk size by 15mm, the difference in braking is very impressive.
The reason I have a set of EBC pads waiting to go on is I over enjoyed this setup after initially fitting it to my last car, and went through a set of standard Brembo pads in less than 10k, as it took awhile for my cost effective supplier to get these in I had to fit another set of Brembo standard pads.
Again for the money this is a very good upgrade.
I think your car has the same brake setup as my previous A6 2.7 Tdi Quattro, 321mm vented front with 302mm solid rear disks. In the end for that car I fitted the A8 360mm setup as above and used the 330mm vented rear disks calipers and carriers from the A6 3.0 Tdi Quattro. If you only do the 360 mm front upgrade you will cook the rear solid disk setup very quickly, and will end up with braking problems, due to over heating after useing the brakes in anger.
What is slightly frustrating with the 302mm rears is that the calipers will accept the 20mm vented disks. At first I sourced the 330mm carriers but then found that the hole distance on the carriers is wider than the 302mm brake Caliper so it was not possible to bolt the calipers to the carriers.. So if you go down this route try to find some 3.0 Tdi rears with the carriers , However having a quick look it seems that the breakers are catching onto this and now selling them separately.
I think the part numbers for the calipers are:
AF0 615 403 H. Left side
AF0 615 404 H right side
From memory I think the 330mm vented rear setup cost me more than the 360mm front.
If you do wish to upgrade the rears I have a spare set of 330mm carriers available.
Upgrading the front & rears at the same time will give you a huge improvement, for which you won’t be disappointed. When I did my original upgrade I also replaced all of the brake hoses using new standard like for like hoses with a good quality Dot 4 brake fluid, I’m not exaggerating as soon as I took the car out of the garage to start the bedding in process, the brakes felt immediately firmer and more responsive and egur to slow the car down, with less brake peddle pressure being applied unlike before the upgrade.
Another interesting side effect after this upgrade was how little the ABS would kick in, before when braking heavily the brakes would snatch quite quickly and the ABS would be going on and off like mad, and after the upgrade it virtually never kick in unless you absolutely stamped on the brake pedal.