M2C competition brakes on F80m3/F82m4

[RElias21]

Originally Posted by M3SQRD

Getting the DSC/ABS lines cycled will potentially address your soft pedal. If it doesn’t then read on…

There’s some brake coding available that supposedly makes the pedal firmer, braking more linear and improved threshold braking on track. All of it sounds to good to be true but pretty much everyone that’s had it coded says it is true. I can’t recall the user names of the two members that claim they were the first figured it out. I’d search in the suspension, chassis and braking forum, and the track forum.

I believe you are talking about daap1193

[M3SQRD]

Originally Posted by RElias21

I believe you are talking about daap1193

It could be. There were main two users discussing these brake coding changes at roughly the same time. I didn’t notice a difference in pedal feel/firmness and braking linearity when I replaced the blue caliper brake setup with the Essex/AP Racing brake kit.

[Track/S]

Originally Posted by RElias21

I believe you are talking about daap1193

No, the spongy pedal is not a coding problem, bleed the abs with an automatic bleeder:

[BSSBMW]

Ive had the full red 6/4 piston calliper 400mm/380mm kit on the my M4 for three years now and have run them with Pagid RSL29 pads, braided hoses and ATE type 200 fluid plus the correct 2NH coding.

Never had an issue with braking performance but one issue i've experienced every time I've been on track (and even on the road occasionally) is pad knock back giving an inconsistent pedal travel to bite point.

I'd learned to work around it on track by giving the brakes a tap before a braking zone but to be honest its not enjoyable and a real let down on this kit for me.

The fronts are going to be swapped out with the AP radical 380mm kit with Pagid RSL1 pads and the rear 380mm 4pistons will be kept but with giro discs and.

After reading this whole thread i'm surprised no one has mentioned pad knock back, there are a few threads/posts on this forum with others who have experienced it with the 2NH brakes.

[jaylazy2020]

Originally Posted by BSSBMW

Ive had the full red 6/4 piston calliper 400mm/380mm kit on the my M4 for three years now and have run them with Pagid RSL29 pads, braided hoses and ATE type 200 fluid plus the correct 2NH coding.

Never had an issue with braking performance but one issue i've experienced every time I've been on track (and even on the road occasionally) is pad knock back giving an inconsistent pedal travel to bite point.

I'd learned to work around it on track by giving the brakes a tap before a braking zone but to be honest its not enjoyable and a real let down on this kit for me.

The fronts are going to be swapped out with the AP radical 380mm kit with Pagid RSL1 pads and the rear 380mm 4pistons will be kept but with giro discs and.

After reading this whole thread i'm surprised no one has mentioned pad knock back, there are a few threads/posts on this forum with others who have experienced it with the 2NH brakes.

Interesting to read. Could you elaborate more how it’s manifests when driving on the road?

[M3SQRD]

Originally Posted by BSSBMW

Ive had the full red 6/4 piston calliper 400mm/380mm kit on the my M4 for three years now and have run them with Pagid RSL29 pads, braided hoses and ATE type 200 fluid plus the correct 2NH coding.

Never had an issue with braking performance but one issue i've experienced every time I've been on track (and even on the road occasionally) is pad knock back giving an inconsistent pedal travel to bite point.

I'd learned to work around it on track by giving the brakes a tap before a braking zone but to be honest its not enjoyable and a real let down on this kit for me.

The fronts are going to be swapped out with the AP radical 380mm kit with Pagid RSL1 pads and the rear 380mm 4pistons will be kept but with giro discs and.

After reading this whole thread i'm surprised no one has mentioned pad knock back, there are a few threads/posts on this forum with others who have experienced it with the 2NH brakes.

Is it possible to add 6 lbf anti-knockback springs? I know the stock pistons don’t have raised seats on their backside but you could find a way to secure them to the spring. Just need to hold it in place long enough to install the piston into the caliper.

[M3SQRD]

Originally Posted by jaylazy2020

Interesting to read. Could you elaborate more how it’s manifests when driving on the road?

Basically, the pad is partially pushing the pistons back into the caliper while in a corner as you release the brake pedal (due to hub flex and/or caliper distortion). So the next time you apply the brakes you have a long pedal before the pads engage the rotor surface. You address this by tapping the brake pedal on the straights so the pads are sitting parallel and flush to the rotor surface. You should not run into this problem with street use.

[jaylazy2020]

Originally Posted by M3SQRD

Basically, the pad is partially pushing the pistons back into the caliper while in a corner (due to hub flex and/or caliper distortion). So the next time you apply the brakes you have a long pedal before the pads engage the rotor surface. You address this by tapping the brake pedal on the straights so the pads are sitting parallel and flush to the rotor surface.

Cheers. I only ever raced karts but a fellow karter that went on to race WTCC used to talk about this happening Seat Cupra R championship particularly when you exited a corner using the rumble strip of a kerb

[BSSBMW]

Originally Posted by jaylazy2020

Interesting to read. Could you elaborate more how it’s manifests when driving on the road?

The same way it manifests its way on the track, after a couple of high G bends.

On track I ended up learning exactly where it would do it so couple prepare by brake tapping before the braking zone but I don't want to have to do that.

[M3SQRD]

Originally Posted by jaylazy2020

Cheers. I only ever raced karts but a fellow karter that went on to race WTCC used to talk about this happening Seat Cupra R championship particularly when you exited a corner using the rumble strip of a kerb

Yep especially when you’re aggressively using the curbs like a pro racer would. It only requires a soft spring pushing back on the piston to eliminate the problem.

[BSSBMW]

Originally Posted by M3SQRD

Is it possible to add 6 lbf anti-knockback springs? I know the stock pistons don’t have raised seats on their backside but you could find a way to secure them to the spring. Just need to hold it in place long enough to install the piston into the caliper.

I had read that this was a solution to the problem (but not with 100% success) with these brakes but have chosen not to bother as I can't be bothered to mess about with them and I also now want to run 18" wheels.

[M3SQRD]

Originally Posted by BSSBMW

I had read that this was a solution to the problem (but not with 100% success) with these brakes but have chosen not to bother as I can't be bothered to mess about with them and I also now want to run 18" wheels.

Alcon CR6420 380 mm-dia rotor and AP Racing CP9668 & CP9660 with 372 mm-dia rotor fit in 18” wheels. I’m running the Essex/AP CP9668/9449 F/R setup.

[Track/S]

Originally Posted by M3SQRD

Basically, the pad is partially pushing the pistons back into the caliper while in a corner as you release the brake pedal (due to hub flex and/or caliper distortion). So the next time you apply the brakes you have a long pedal before the pads engage the rotor surface. You address this by tapping the brake pedal on the straights so the pads are sitting parallel and flush to the rotor surface. You should not run into this problem with street use.

It sounds strange, I have 55.000km with 2nh brakes and I have never experienced this issue, i use the car a lot on mountain trips, where the brake pedal is used 10 times more than on a track.

Something similar happened to me until I deactivated several functions via coding that must be deactivated for track, but after that operation everything works normally.

M5 F10 with ccb uses same front calipers with wider pads, it should have this issue even more often...

Originally Posted by M3SQRD

Alcon CR6420 380 mm-dia rotor and AP Racing CP9668 & CP9660 with 372 mm-dia rotor fit in 18” wheels. I’m running the Essex/AP CP9668/9449 F/R setup.

Ap9449 can be used with 380mm rotor of m2c.

[M3SQRD]

Originally Posted by Track/S

It sounds strange, I have 55.000km with 2nh brakes and I have never experienced this issue, i use the car a lot on mountain trips, where the brake pedal is used 10 times more than on a track.

Something similar happened to me until I deactivated several functions via coding that must be deactivated for track, but after that operation everything works normally.

M5 F10 with ccb uses same front calipers with wider pads, it should have this issue even more often...

You’d have to simulate hitting an aggressive track curb on the street if you really want to find out

Wider pads - Is the F10 M5 caliper physically wider or is it the CCB rotor is thinner than the iron rotor? I’ve always thought the F10 CCB caliper, F8x CCB caliper and F87 iron caliper were all identical.

[BSSBMW]

Originally Posted by Track/S

Something similar happened to me until I deactivated several functions via coding that must be deactivated for track, but after that operation everything works normally.

Can you elaborate on this please?

[Track/S]

Originally Posted by M3SQRD

You’d have to simulate hitting an aggressive track curb on the street if you really want to find out

Wider pads - Is the F10 M5 caliper physically wider or is it the CCB rotor is thinner than the iron rotor? I’ve always thought the F10 CCB caliper, F8x CCB caliper and F87 iron caliper were all identical.

The calipers are same, the pads and discs are not, m5 and m6 use 410mm discs

M5/M6 CCB pads vs m2/m3/m4 ccb/steel pads

[M3SQRD]

Originally Posted by Track/S

The calipers are same, the pads and discs are not, m5 and m6 use 410mm discs

M5/M6 CCB pads vs m2/m3/m4 ccb/steel pads

Thanks. Did not know they used a 410 mm-dia brake rotor and pads with a ~10 mm longer radial depth.

[tropicatango]

Originally Posted by OzcarM3

only other photo I have is with my standard 20" wheels.
did a track day last weekend with my 18" without a problem.
note however, I use 380mm rotors.

Can you please share what rotors you used, brand and where you bought it please

[Track/S]

Originally Posted by tropicatango

Can you please share what rotors you used, brand and where you bought it please

Paragonbrakes have 380x36mm discs for F8X with 2NH, but you need custom brackets for those calipers, i can provide it.

[jaylazy2020]

After a nice 300km/h run this morning and but having to do any heavy stops due to light traffic the discs still have the smearing return.

They feel ok in general but it’s hard to have confidence in them!