Brembo GT-R as a solution to B8 brake heat

B8 S4
#1

I’ve been getting great mixed street/track use out of my 380mm AP Racing BBK, running Pagid Yellow RS29 on it full time. I’m on my 3rd set of pads and the discs are down to 30.7mm, so they’ll need to be replaced in the next 6-10 months depending on when the track days fall.

Rather than replace the rotor rings on the AP kit, I might upgrade to something better. This Brembo GT-R kit seems to have grafted a few techniques from the race calipers, without requiring semi-annual rebuilds. It’s a forged, one piece caliper that allegedly lets all of the heat dissipate.

It’s a bit spendy at $8500.

http://www.redlinespeedworx.com/brembo-presents-gt-r-braking-systems/

#2

If I were going to spend that cash, if get the rs5 ceramics.

Is there something that you don’t like about the AP? You seem to have enough miles on them, and they have been working for you.

#3

If your problem is heat, a forged caliper won’t help you.
If anything, a forged caliper has even less material than a cast one, and has less material density for heat dissipation at the caliper.

You are better off figuring out a way to duct air more effectively to the brakes (if you haven’t already done so). Your gains will primarily be found there since you already have a 380mm bbk.
Have you tried removing the rotor backing plate, or run airscoops on the lower control arm?

#4

Yeah, I’d recommend taking off the dust shields if they haven’t been taken off already and getting a ducting setup fabricated similar to what I used to have.

#5

I do want either the RS5 ceramic kit or this kit. I’m actually leaning towards the steel.

I think you guys are underestimating how the piston seals in this kit mitigate fluid boil.

#6

I get that - but TI backing plates do the same thing, and are more effective than the race spec seals.
Try those first if your concern is fluid temps. They do wonders–so much so that you will begin finding shortcomings of your current favorite pad (potentially!).

#7

If we break down what this kit actually is, it’s a Brembo GT disc coated in zinc, and a $3500 caliper (per side) from the race division that is appropriate for street use (high service interval). Respectfully, the caliper does a bit more than a titanium dust shield.

Relative to the AP racing kit, I’d have a larger (but more expensive) pad shape. I’d be going from a multi piece bolted cast caliper to a forged monobloc caliper. The caliper would be completely open on the top. The whole unit should weigh 1-2 pounds less. The disc would be of a much better metallurgy.

#8

Oh, I know how cool the Brembo pistons are (literally since they’re ventilated). Rubber boots will crack. It’s a yearly cost for me (I’ve just accepted it). A good Titanium (alloy) shield will help mitigate it from turning instantly crispy, but it’s just the reality (race calipers have no rubber boots - and require yearly rebuilding).

Also, I think the zinc rotor coating will burn off on track use (I think).

I guess another thing would be diminishing returns I suppose.

Are you having issues with the current set up with fluid boiling? Air flow makes a HUGE difference - and would be cheaper than going Brembo (plus I’m for the argument that you’d need airflow no matter what direction you went with).

The RS5 has stock NACA ducts and I just had my local shop (Achtuning) fabricate brake scoops to collect the air and direct it to the rotors. I’ve noticed a good temperature drop in regular street driving. Can’t wait for Laguna Seca next month!

#9

Which Laguna event did you reg for?

#10

Sorry to take this OT - but can you post more details about the naca ducts?
Were you able to re-use the RS5 part and bolt it in? I’d like to do something similar. The brakes on this platform retain a TON of heat bc there is simply too little air getting in there.

Westwest - I get your point on the calipers 100%.
I was only hoping to point out alternative solutions which perhaps should be exhausted prior to making such a dramatic leap. Perhaps it’s the grassroots track rat that I tend to be, but I always look for ways to optimize what parts are already on the car before re-investing (or simply spending!) on new parts for improvements.

#11

Hooked on Driving - Sept 10 -11

The 10th is a private track day.

#12

Sure thing! I had them custom made:
http://audirevolution.net/forum/index.php?topic=2372.msg65634#msg65634

This was done before I knew how it was on the RS5:

https://lh3.googleusercontent.com/-j7NiDDdjA7Q/UxP0vNdNZRI/AAAAAAAAENE/vB7QUkDZiCE/w719-h479-no/IMG_2037.JPG

#13

Looks like it already sold out. That would have have been tough as I’m returning from an international trip on the 10th.

http://www.hookedondriving.com/event-details/MRLS,_THURSDAY,_September_11

#14

I’ve been agonizing about these brakes for months. Can’t decide whether to spring for GT-R or settle on GT. I’d say I’m favoring GT-R, but there’s very little data available. Most cars that have them are tuner show cars. I feel the B8 platform represents a bargain in that I only need fronts; normally even on a comparable car like an M3 you’d do front and rear. So there is an aspect of relative affordability.

I’m probably going to decide in December and install in January.

http://i61.tinypic.com/2maame.jpg

http://i60.tinypic.com/j9aa1u.jpg

http://i60.tinypic.com/35aoc44.jpg

http://i61.tinypic.com/2w4agpl.jpg

#15

any reason you’re leaving the AP’s?

#16

Just needs a bigger Brembo logo, and you’re all set. :slight_smile:

My brembos saved my life (or my RS4’s life at the very least) the other day. Was going 35 mph and someone just pulled out from a sidestreet on my right to make a left turn. She didn’t even fucking look and just pulled out. I went from 35 mph to 0 in what felt like about 10 feet.

#17

AP is adequate and in another league than anything OEM. Brembo owns AP. AP is a good value and gets the job done. Brembo is simply the more premium supplier with the more expensive tooling, newer techniques and designs, better metals. I want to try something upmarket to see if I get an improvement. At a minimum, I know I’m getting a pad that is about 60% larger. The GT caliper is larger too, but heavier. The GT-R is the same size but would keep the AP weight. Both the kit I have now and the GT and GT-R are 380mm. Maybe the higher quality brembo steel won’t produce as many hairline surface cracks as the AP does (even though they are normal and small enough to be safe).

An S4 can keep up with an R8 for a little while, but eventually it can’t stop like the R8 can. The least consistent thing after 10 laps is braking ability. It’s still pretty amazing, but you have to dial back your following distances on supercars. I know, first world problems.

If buying $9000 brakes saves me from rear ending a McLaren 650S at the next track day, I can see value in it. NorCal has had a lot of exotics lately…

#18

Buy a 944 track car for that money.

#19

That McLaren guy could by an R8 GT for the replacement parts he needed and depreciation he saw tracking it.

#20

IDK man, I think you’re just shopping different price points. AP Racing probably makes kits of similar caliber…plenty of GT race teams run their setup http://www.apracing.com/products/race_car/brake_calipers/gt_range.aspx.

Brembo still buys parts from T2 and T3 suppliers, which didn’t work out too well for Lewis Hamilton: http://uk.reuters.com/article/2014/07/19/uk-motor-racing-prix-brakes-idUKKBN0FO0UH20140719

Have you tried some different pad compounds? I think no matter what, this car is a pig at 3900 lbs, and with the R-comps, you’ll overwhelm the brake system no matter what if you are driving fast enough. Are you using Ti shims? I know QUA77RO had issues even with his stasis alcons and xp20’s…I believe he switched to some other pad compound, something like they use in nascar.