Going for a bit of a brake upgrade in the car as hopefully it will be remapped in the next few weeks with the hybrid on. I want to do a few track day this year but don't want to go too mad with big brakes that mean big wheels. Part of the problem with the S4 brakes on the car at the moment is they are a sliding caliper brake so just one piston and the pad stops very close to the disc slightly dragging which doesn't help.
All performance cars usually have multi pot brakes as these have many advantages.
Thus looking around I saw that several people have fitted Audi Q5 brakes to their A4's and A5's . These are a 4 pot Brembo brake caliper that uses a 345mm * 30mm disc the same size as the S4.Here's a picture of a test fit of the calipers with the standard 17 inch wheels I use with winter tyres.
A few mm clearance but they do fit. I think they need something like a 3mm spacer just to give a little more clearance on the spokes
The pads in the caliper are the same size as used in the Subaru STI and EVO 2008-2015 so the choice of pad materials is immense, almost every compound from every manufacturer is available to fit these.
Bought a set of Redstuff for normal road use, yet to decide what to use for the track.
The big problem with the standard set up even if I fitted RS4 brakes is the lack of cooling, there really must be very little air getting to the brakes . So to address this issue and give them a fighting chance again after doing some surfing found some solutions to this I hope.
Porsche Macan Turbo brake ducts.
This is what the look like on the Macan, which is based on the Q5 which is based on the same platform as the A4/ A5. The Macan has 20-21 inch wheels and big brakes, you can see the brake ducts clip onto the steering rack arms by the track rod end. On the A4 they need a little shortening on the one end by about 1cm as otherwise they foul the ARB but apart from that they fit fine.
Notice the almost non existent brake backing plate, this is standard so I will be chopping the thin bit of ally thats on the A4 to match this. It just basically provides screening from direct radiated heat for the ABS sensor and track rod end. But allows a lot of air flow to the centre of disc and the face.
Cheap way of getting Porche bits on the car too as 2 ducts and 2 clips were £14 from my local Porsche dealer. Had a mooch at the cars as well whilst I was there, very nice
Now just need to get some air in the wheel well. Bought some Audi TTRS wheel well air vents. I have fitted one side nearly just needs some trimming and it looks quite good, almost OE.
It has a NACA duct that feeds air through a vent like the RS4 / RS5 but also has quite a large wheel well grating that allows air in. I intend to buy some cheap fog light covers from Fleabay and mod them so this will allow a lot of air to find it's way to the wheel well on a track day.This is a picture from this thread where I saw this done.
He used Phaeton back plates and scoops. A more expensive solution.
You could use any 345 * 30 mm disc but decided to go for the ECS 2 part disc. Expensive but hopefully they will do the job. These have directional vanes which RS4/5 brakes don't have . Not too many drilled holes. As long as they don't get too hot cracks shouldn't be an issue.
The weight saving with the discs and much lighter caliper is quite surprising, The discs are 7.5 Lb lighter and the caliper is about half the weight as it's alumimium as opposed to the predominantly cast iron standard item. this all adds up to a much reduced unsprung weight.
I painted my calipers with smooth black hammerite with some white Brembo stickers.
The Q5 uses the TRW 345mm caliper in some models and the Brembo in more potent versions. They use the same master cylinder in both and the same as the A4, so another reason for sticking to this kind of solution. An RS4 uses a different Master cylinder probably to cope with 8 pots on a caliper.