westwest888

I recently purchased a professionally refurbished and certified used Brembo GT-R BBK from a friend of a friend. The new discs are 380mm x 32mm, to the stock 345mm x 30mm. They're made of a very high quality metallurgy, which is then coated in zinc for rust resistance. The hardware that holds the ring to the plate is top notch in Brembo's application. Some cheaper BBK's use fasteners that don't allow the disc to expand properly under high heat. This has been a problem for me in the past.

The GT-R kit is similar to the GT, except the caliper uses a higher grade of aluminum and is carved in a 4 axis CNC machine from a monoblock. It also has steel inserts around the pistons instead of rubber seals, which hold up better under heat. Lastly the entire caliper is coated in nickel, which both rejects heat and makes it easier for the pistons to slide.

The stock rotor is 23 pounds; the Brembo 21 pounds. The stock caliper is 18 pounds; the Brembo is 13 (with pads and mounting bracket).

I sourced Brembo's endurance track pad, the RE10. It should exceed the Pagid RS-29 that I had been using for the track.

jeff33702

Those look pretty serious.

iNfiNkC

yummy

westwest888

I did the RS5 conversion in the rear. The rotors were $1100, the bearings were $300, and the hubs were $600. You have to replace the hubs with RS5 hubs, which are 4.9mm wider than OE. To match the track I put H&R 5mm spacers on the front axle. When you pull the hubs off you usually damage the bearings, which is why those also must be replaced.

The OEM rotors in the rear are 17 pounds; RS5 are 13 pounds; lightest aftermarket is 11 pounds but they crack after track use (ask me how I know).

JSLevine05

What exactly drives the change in the bearings and hubs for the RS5 conversion in the rear? I thought the RS5 caliper assembly was the same for the B8 S4, the part numbers are a basic match.

westwest888

The size is the same (330x28) so we can use the same caliper. The RS5 disc won't fit on the S4 hub. So you have to remove it, and press new bearings into the assembly with a very strong multi-ton vice.

JSLevine05

Thanks for that information, I had thought they would be direct bolt on.

What size wheels are your running? Also did you have to replace the dust shield when you put on the BBK or were you able to modify the existing one?

westwest888

19x8.5 with 235/35ZR19 Pilot Sport Cup 2 (both available on TireRack). They're about 245 width IRL, as cups run wide. They have grip for days and turn in a bit better than a 255. 265 must be like trying to change direction in the Titanic.

westwest888

I use Brembo's endurance pad, the RE10. It's pretty expensive at $795 retail. It lasted 7 track days.