mhoran89

Hello there. I've got a 2014 B8.5 A5 cabriolet that has some intake, exhaust, and has Stage 1 APR tune. I usually run the 93 octane tune but also have regular access to E85 for more power! Ran 13.46 in the quarter mile.

I feel like I am left looking for more braking power when driving spiritedly. I currently have good quality rotors that I did around 13K miles ago. Using Stoptech Z23 Evolution Sport brake pads and have a fairly recent flush (1 year or 13K ago).

I have this strange occurance that seems to happen when the brakes are cold. If I need to roast the brakes hard (close to panic stop) and the brakes are not warmed up I get ABS to panic and kick in and pulse the pedal quickly. It is kind of frightening but only lasts breifly. If I get off the pedal and then go back to it hard, it grabs perfect and stops quick on a dime. If I have been on the brakes any amount recent, and they are holding any heat, then the car stops great and pedal modulation is very good. No ABS presence at all. Has anyone experienced anything like this? I had no issues like this with the same brand pads on my A8L. And no such experience on any other Audi or any other car I have owned previousily.

Additionally, I seem to be depositing pads on the rotor surface unevenly, since I am getting vibrations during heavy braking from higher speeds (when I introduce heat into the rotors). I have bed in the brakes again and it helps marginally. I am wondering if these Stoptech Z23 Evolution pads are not enough...

I have been eyeing ECS upgrade to go to S4/S5 rotors. They sell the rotors and caliper bracket and then you go to any OEM or off the shelf aftermarket S4/S5 brake pad (I am a sucker for the lower dust Ceramic options). Has anyone gone to the S4/S5 rotor option on an A4/A5? At this point I am pushing more boost and am surpassing stock S4/S5 power levels and am wondering if the increased size rotors (and more thermal mass) would help. Seems like the larger rotors may help marginally with braking force due to a larger lever (simple physics) but also resist heat soak since they've got more metal and also possibly cool faster due to more surface area.

Lastly, will the (OE Part Number: 8T0601025CA8Z8) stock 18" wheels (10 spoke, 18 x 8.5", 29mm offset) fit with S4/S5 brakes? It seems as though these wheels were available on the S5 but just want to make sure before I make a perfectly good set of wheels I own unusable on my car.

I have never had these issues with the A8L but those were the Audi "quasi two piece design" and were huge (400mm).

Any input is greatly appreciated in advance.

mhoran89

No input whatsoever? I am surprised...

mhoran89

So no one has done the S4 or S5 front rotor upgrade on an A5?
Any concerns with doing this in terms of brake bias? Considering the rear rotors/pads won't be changing.
Thanks.

mhoran89

what are folks running for brake pads on their b8 a5 cars?
anyone have experience with hawk hps or hawk hps 5.0 pads? i had the old hps formula on a subaru and they were phenomenal... thinking of taking that route again for my next set of pads.

mhoran89

well I just threw on some stock size EBC rotors (slotted in the front) and Hawk HPS 5.0 pads. The fronts are still bedding in.
Will report back when I have some more miles on them.

mhoran89

Hawk HPS 5.0 pads are working out very well. They like a little heat in them but nothing like the stoptech z23 pads which were unbearable. dusting has been heavier than ceramic but that was expected.