BMW M3 Forum (E90 E92) - View Single Post - 355x32 vs 370x36 BBK setup for track/race

M3SQRD · 08-29-2024, 10:37 AM

I have two PFC brake kits on my e92 M3s.

PFC Z54/Z45 which uses F/R 372/355 mm OD slotted rotors. This is the best brake kit that was available for the e9x M but PFC stopped supporting the aftermarket brake kits except for Porsche GT cars. Front caliper uses a 29 mm thick brake pad. The 372 mm V3 rotor has performed flawlessly at SP Main and Shenandoah, VIR Full and WGI. I can’t speak to the longevity of Paragon rotors but the PFC 372 mm V3 rotors last at least 28 track days (with PFC pads).

Z31/Z31 which uses F/R 372/371 mm OD slotted or dimpled rotors and four pads/caliper. This kit was released ~3-4 years before the Z54/Z45 kit. The calipers are a monobloc design with a fixed bridge and, based on its compact size (18 mm thick pads), a PFC engineer told me it’s the stiffest caliper they’ve designed. Once again, the 372 mm V2 rotor has no trouble handling SP Main and Shenandoah, VIR Full and WGI. The 372 mm V2 rotors also last at least 30 track days with PFC pads. Fits under all 18” wheels, including OEM, I’m aware of (my wheels in addition to other people’s wheel setups). This kit is a step down compared to the Z54/Z45 due to the use of the V2 rotor hat retention design and the 18 mm thick pads (more frequent pad changes which requires the removal of the caliper).

Based on my experience with both PFC kits, I would not run a 355 mm OD rotor on the e9x M. I believe you’ll run into brake heating issues with a 355 mm OD rotor. There’s a good chance the brake bias will shift rearward which isn’t necessarily an issue. At times, I’ll run a more aggressive pad on the rear to move the brake bias rearward. Fits under all 18” wheels, including oem, with plenty of clearance.

In addition, on my f82 I’m running the Essex/AP Racing CP9668/CP9449 372/365 mm OD rotors. This kit performs extremely well but I’m thinking about getting new caliper brackets so I can run a 378 mm OD rotor. The 372 mm rotor has trouble with 45 min sessions but works great for 20-25 min sessions. I definitely would not step down to a front 355 mm OD rotor.

08-29-2024, 10:37 AM	#2
M3SQRD Major General 7938 Rep 9,881 Posts Drives: 330G20,240F22,M3E92,F82,MCSR56 Join Date: Jun 2009 Location: Mid-Atlantic iTrader: (12)	I have two PFC brake kits on my e92 M3s. PFC Z54/Z45 which uses F/R 372/355 mm OD slotted rotors. This is the best brake kit that was available for the e9x M but PFC stopped supporting the aftermarket brake kits except for Porsche GT cars. Front caliper uses a 29 mm thick brake pad. The 372 mm V3 rotor has performed flawlessly at SP Main and Shenandoah, VIR Full and WGI. I can’t speak to the longevity of Paragon rotors but the PFC 372 mm V3 rotors last at least 28 track days (with PFC pads). Z31/Z31 which uses F/R 372/371 mm OD slotted or dimpled rotors and four pads/caliper. This kit was released ~3-4 years before the Z54/Z45 kit. The calipers are a monobloc design with a fixed bridge and, based on its compact size (18 mm thick pads), a PFC engineer told me it’s the stiffest caliper they’ve designed. Once again, the 372 mm V2 rotor has no trouble handling SP Main and Shenandoah, VIR Full and WGI. The 372 mm V2 rotors also last at least 30 track days with PFC pads. Fits under all 18” wheels, including OEM, I’m aware of (my wheels in addition to other people’s wheel setups). This kit is a step down compared to the Z54/Z45 due to the use of the V2 rotor hat retention design and the 18 mm thick pads (more frequent pad changes which requires the removal of the caliper). Based on my experience with both PFC kits, I would not run a 355 mm OD rotor on the e9x M. I believe you’ll run into brake heating issues with a 355 mm OD rotor. There’s a good chance the brake bias will shift rearward which isn’t necessarily an issue. At times, I’ll run a more aggressive pad on the rear to move the brake bias rearward. Fits under all 18” wheels, including oem, with plenty of clearance. In addition, on my f82 I’m running the Essex/AP Racing CP9668/CP9449 372/365 mm OD rotors. This kit performs extremely well but I’m thinking about getting new caliper brackets so I can run a 378 mm OD rotor. The 372 mm rotor has trouble with 45 min sessions but works great for 20-25 min sessions. I definitely would not step down to a front 355 mm OD rotor.
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