Stoptech C43 front BBK

[r4dr]

The C43 rear rotors are 324 mm. Kinda sad that they didn’t try using 328 mm rotors. Would give those looking for floating rotors for their stock or 996 calipers a good option.

328 mm rear floating two-piece rotors would still have the issue of the 2-piece hardware not clearing the stock pads or wider annulus 996 pads.

[r4dr]

When you say full braking zones, are you borderline triggering ABS at maximum threshold braking? What locks up first, front or rear?

I'm guessing rears based on the sideways feel you described? I'd imagine front lockup would just induce under steer and plow forward.

[CrookedCommie]

At the last event I drove three E46M's back to back, all cars ran on similar Pirelli DH's
1. My stripper with AP front and rear using 1.11, MK20
2. WRL car with CP43 and stock rear using mix of 1.11 and DTC-60/70, MK60
3. Track setup but full weight with Stock front and rear and DTC-60, MK60

What we found with these setups in full-braking zones, the rear will lose grip and send the car sideways slightly. I'm thinking it has too much rear or not enough front?

On my car adding the rear AP kit seems to have helped - the sideways send is not as pronounced. I also measured the front rotor temps, and they are WAY too high for 1.11's. I'm switching to 3.12 front and keeping the rear at 1.11 and will test again. Unfortunately I only did a dozen laps last year in my car, and it'll be a while again this year before I can update. This is obviously not a scientific test, and in addition to all the differences, I had a brand new diff that was spewing fluid everywhere (hence the only dozen laps).

[SQ13]

Will the PFC DD rear rotors fit the C43 kit? I was able to retain the parking brake and have enough pad clearance to disk hardware to run this rotor with the rear AP kit.

The C43 rear rotors are 324 mm. Kinda sad that they didn’t try using 328 mm rotors. Would give those looking for floating rotors for their stock or 996 calipers a good option.

[SQ13]

so then 996 conversion for the rears. Anybody figured out the brake bias yet? If its not too far off. It should be ok. One could play around with the pads in order to compensate for this

Brake bias with different rear caliper and pad size options. What throws me off is how the narrower PFC 7855 pads bring the bias more rearward compared to the stock sized PFC 548 pads. And the bias appears to be drastically changed with a C43 front and rear kit..almost 50:50.

https://drive.google.com/drive/folde...LudDTkQCWKsp-P

I’m leaning towards trying 996 rears with the narrower D738 pads and PFC DD rotors. To bring bias more towards the rear, something like Ferodo DS11.1 front pads (since PFC 08s aren’t available for the C43) and PFC 11 rears.

Edit: The C43 kit comes with DR21 pads, which are 43 mm wide, not the 50 mm wide DR98 pads that I used to calculate bias. Just learned this after calling StopTech.

[CrookedCommie]

Did you have to run a different pad than what Essex recommends to clear the hardware?

Actually switched to the biggest Ferodo pad that will fit the caliper - I can get part numbers if you need. Same pad shape but bigger radial depth, similar to the front D43 vs D50. It's close, but the bigger pad cleared the hardware. C43 is a bigger rear caliper than AP's rear kit, so not sure what will work there.

[r4dr]

Will the PFC DD rear rotors fit the C43 kit? I was able to retain the parking brake and have enough pad clearance to disk hardware to run this rotor with the rear AP kit.

Did you have to run a different pad than what Essex recommends to clear the hardware?

[CrookedCommie]

Will the PFC DD rear rotors fit the C43 kit? I was able to retain the parking brake and have enough pad clearance to disk hardware to run this rotor with the rear AP kit.

[Jevi Javi]

so then 996 conversion for the rears. Anybody figured out the brake bias yet? If its not too far off. It should be ok. One could play around with the pads in order to compensate for this

[chapmans]

is this confirmed? rear C43 kit does not support parking brake? I thought i had read somewhere that with the use of an adapter/spacer it could be used? maybe wishful thinking on my part...

Not in a hurry to swap my OEM rear brakes. But it is on my to do list.

The bimmerworld description specifically says it deletes the parking brake. I believe the rotor rear hat doesn't have the drum area for the parking brake shoes to contact.

I ended up ordering front/rear trophy instead. I'd still prefer the C43 if there actually is a work around for that parking brake.

[eacmen]

Typically stoptech engineers their kits as front only with OE rears or front and rear. If you buy a front only kit you can’t typically just buy rears later on.

If you forsee wanting a rear kit later on just spend the money for the front and rear kit so the bias matches up correctly for the OE master cylinder.

[Jevi Javi]

Please update with what you decide. I have C43 front kit on order and am trying to figure out what to do for the rears. The rear C43 kit won't work because I want to keep my parking brake.

is this confirmed? rear C43 kit does not support parking brake? I thought i had read somewhere that with the use of an adapter/spacer it could be used? maybe wishful thinking on my part...

Not in a hurry to swap my OEM rear brakes. But it is on my to do list.

[SQ13]

Please update with what you decide. I have C43 front kit on order and am trying to figure out what to do for the rears. The rear C43 kit won't work because I want to keep my parking brake.

Right, I don’t want to delete the parking brakes either. No one has been willing to help me out with the brake bias calculation and I can’t access the calculator myself either, so I’m just stuck until I get an answer. I know I can do a 996 rear conversion with the Trophy ST40 355mm kit, and I might end up going for that if my C43 bias question remains unanswered.

[chapmans]

I was able to get the information from ST. It’s 38/44mm. Just need to figure out what the bias would be with stock rears and 996 conversion rears. I hope I don’t screw up the 50 different calculations Build Journal has on their website lol.

Please update with what you decide. I have C43 front kit on order and am trying to figure out what to do for the rears. The rear C43 kit won't work because I want to keep my parking brake.

[eacmen]

Zeckhausen are also super knowledgeable and have a huge catalog of all rebuild parts, just need a part number.

Sent from my SM-G950U using Tapatalk

Concur. By far the most knowledgeable source for anything stop tech.