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      10-29-2020, 08:20 PM   #23
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Originally Posted by FormulaMMM View Post
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Originally Posted by 4play View Post
I suspect the OEM BMW CCB would perform much better on track if they had adequate cooling. If you could keep the disc surface just a bit cooler, there would be hardly any oxidization and the brake discs would last a really, really long time. Of course, the flip side is that the brakes would be quite cool by the end of long straights / sections not requiring brakes, and might not perform as well during initial brake application.
I think that's true, especially up front. and given how hot they run too much cooling is pretty unlikely.

Worth keeping in mind the Porsche is on their 4th gen PCCB development (20 years). I don't know where M's F8x CCB system would plug in on the developmental spectrum, but probably safe to assume from performance & durability standpoints they're not equal. Just as not all iron rotors are equal in quality or longevity.

Z/28 system was designed from the outset for track use. Discs aside, a comparison in pad wear rate between that system and M's indicates differing design/purpose. I'd estimate at least 2x faster pad wear rate for the M system. GTS is faster, but it ain't heavier or harder on brakes...

Bummer because I found the M system to be excellent performance wise, absolutely consistent, even when running hot enough to melt skin.
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Originally Posted by h_bakken View Post
What is GM CCB
General Motors - It's the Brembo CCM brakes, as found on Ferrari/Alfa/Maserati, Chevy, and other vehicles. Our brakes are Brembo CCB, as are AMG/Porsche/VAG.

Both have discs made of silicon carbide with carbon fiber reinforcement, just 2 different construction methods. CCB is a ceramic disc with a wear layer on the top (a little over 200g worth on our CCB front discs), while CCM is a slightly different type of ceramic material with no wear layer.

I suspect the OEM BMW CCB would perform much better on track if they had adequate cooling. If you could keep the disc surface just a bit cooler, there would be hardly any oxidization and the brake discs would last a really, really long time. Of course, the flip side is that the brakes would be quite cool by the end of long straights / sections not requiring brakes, and might not perform as well during initial brake application.
I love this forum, there is so much information shared would be impossible to find otherwise.

I'm gonna track mine first time with the CCB and decide what to do next after...
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      10-29-2020, 09:19 PM   #24
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Originally Posted by FormulaMMM View Post
I think that's true, especially up front. and given how hot they run too much cooling is pretty unlikely.

Worth keeping in mind the Porsche is on their 4th gen PCCB development (20 years). I don't know where M's F8x CCB system would plug in on the developmental spectrum, but probably safe to assume from performance & durability standpoints they're not equal. Just as not all iron rotors are equal in quality or longevity.

Z/28 system was designed from the outset for track use. Discs aside, a comparison in pad wear rate between that system and M's indicates differing design/purpose. I'd estimate at least 2x faster pad wear rate for the M system. GTS is faster, but it ain't heavier or harder on brakes...

Bummer because I found the M system to be excellent performance wise, absolutely consistent, even when running hot enough to melt skin.
Porsche simply uses Brembo/SGL rotors and calipers. The 4th gen PCCB is really just Brembo's 4th gen CCB. It's the same as the BMW/Merc/Audi/Lambo/Bugatti CCBs. Each manufacturer might specify a slightly different pad compound or rotor size, but the rotors are the same construction. I don't know when the latest revision was, but it's safe to assume the GTS has either gen 3 or gen 4.

I don't know that CCM brakes are necessarily better on track than CCB. They've had a similar number of development cycles, and the Z28 is on an older spec of CCM (the newest spec uses CCM discs AND pads).

The real way in which the Z28's system was designed for the track is that the Z28 has much better brake cooling than the GTS. There are dedicated ducts from the front bumper into the wheel well that are directed at the rotor. Additionally, the backing plate / dust shield is very small to allow that airflow to better cool the rotor.

Obviously, the Z28s setup is not as good as a full on racecar setup (a la M4 GT4) with flexible ducts leading to a vented backing plate, but the GTS has no brake cooling and huge backing plates that hold in heat. I think if you added the GT4 ducts and took away the ridiculous backing plates, you would see disc and pad life pretty similar to the Z28.

Problem is, you have to hack apart the front bumper to do so and the BMW Motorsports parts are stupidly expensive for what they are. The full setup (ducts, hoses, double vent backing plate, GT4 splitter) is nearly $10k. That said, it's pretty ridiculous for a $135k track day special to have milled aluminum uprights, 3 way suspension, CCBs, etc but no brake ducting whatsoever.

Last edited by 4play; 10-29-2020 at 09:29 PM..
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      10-30-2020, 08:31 AM   #25
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Quote:
Originally Posted by 4play View Post
Porsche simply uses Brembo/SGL rotors and calipers. The 4th gen PCCB is really just Brembo's 4th gen CCB. It's the same as the BMW/Merc/Audi/Lambo/Bugatti CCBs. Each manufacturer might specify a slightly different pad compound or rotor size, but the rotors are the same construction. I don't know when the latest revision was, but it's safe to assume the GTS has either gen 3 or gen 4.
Different cross drill pattern, surface finish, wear indicators vs. no wear indicators (997 gen 2 did have indicators). I’m not sure why there’d be certainty that the construction of the ccb rotors/system for the street M3/M4 = that which was intended for use on the 991 GT3 RS, or the Chiron. Is every Brembo iron rotor equally durable?









Anecdotally, there are stories of RS's and 918's with thousands of abusive track miles, original discs. Track with guys who have run the PCCB for seasons without issue. Agreed on the lack of cooling as an issue for the M system, but doubt that even with added cooling they'd get there.

Not claiming GM CCM > CCB, just that the wear rate of the pads and apparent sturdiness of the systems are not equal based on my track use.

Is cooling a factor? Without a doubt. The only factor? I don't think so. BMW spec'd a comparatively weak version of the Cup 2 and speculate they did the same with the brakes. Fit a different rear pad to a street-oriented ccb system and called it good. And then half assed it on the (lack of) cooling as well.
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      10-30-2020, 11:52 AM   #26
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Originally Posted by FormulaMMM View Post
Different cross drill pattern, surface finish, wear indicators vs. no wear indicators (997 gen 2 did have indicators). I’m not sure why there’d be certainty that the construction of the ccb rotors/system for the street M3/M4 = that which was intended for use on the 991 GT3 RS, or the Chiron. Is every Brembo iron rotor equally durable?

Anecdotally, there are stories of RS's and 918's with thousands of abusive track miles, original discs. Track with guys who have run the PCCB for seasons without issue. Agreed on the lack of cooling as an issue for the M system, but doubt that even with added cooling they'd get there.

Not claiming GM CCM > CCB, just that the wear rate of the pads and apparent sturdiness of the systems are not equal based on my track use.

Is cooling a factor? Without a doubt. The only factor? I don't think so. BMW spec'd a comparatively weak version of the Cup 2 and speculate they did the same with the brakes. Fit a different rear pad to a street-oriented ccb system and called it good. And then half assed it on the (lack of) cooling as well.
Those are simply different generations of Brembo/SGL CCB.

The early gen rotors don't have the surface crazing, and you can see the individual short fibers used to reinforce the silicon carbide ceramic.

The very first gen (found on 996 GT3) has the same drill holes as a steel rotor:



Brembo eventually realized that they needed a different drill pattern to offgas/cool more effectively (Gen 2):



Next, they added wear sensors (Gen 3):



The next generation used the new surface treatment with crazing (Gen 4):

918 Spyder


Chiron


The basic construction (silicon carbide ceramic with carbon fiber reinforcement and a gas-deposited friction face with crazing) is the same across cars. What changes is rotor diameter, presence of wear indicators, rotor thickness, mounting hat design, cross drilled holes number/location, backing plate, cooling ducts, and most importantly, pads.

Pagid makes ceramic pads for Brembo and AP, and I suspect the Z/28 pads are closer to an RSC-1 (their track CCB pad product). Pagid claims that the RSC-1 pads last longer and are easier on the rotors, which would match with your experience with the Z/28.

In talking with a couple of manufacturers (StopTech/Centric/APC), the pads on the M4 are definitely not RSC-1 - they are much closer to a semi-metallic adhesive brake pad that you might see on "standard" iron rotors. So you get accelerated rotor wear (not helped due to the heat) and way shorter pad life when used on track.
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      10-30-2020, 12:16 PM   #27
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Quote:
Originally Posted by 4play View Post
Those are simply different generations of Brembo/SGL CCB.
Good info. The presence of wear indicators gen 2 PCCB seems to suggest M's system has more in common with that older design/construction. This is a gen 2 PCCB indicator



If one of the main parameters of evaluating rotor condition is changed, then that suggests an evolution of construction and wear characteristics. Gen 3 PCCB don't have the indicators, as far as I know.

Combine previous gen rotor tech with your pad theory and lack of cooling, and you get the very dissimilar results for M's system vs GM's or Porsche's.
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      10-30-2020, 12:46 PM   #28
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Can anyone chime in as to why others that run the BMW CCB just end up suggesting that one should replace the pads themselves before half life and not to worry about rotors until later on?

And has anyone seen Proceq (or Carboteq) CCB wear tester? it utilize the three positions around the rotor hat apparently. check out the link below. Its on youtube

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      10-30-2020, 01:27 PM   #29
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Quote:
Originally Posted by FormulaMMM View Post
Good info. The presence of wear indicators gen 2 PCCB seems to suggest M's system has more in common with that older design/construction. This is a gen 2 PCCB indicator



If one of the main parameters of evaluating rotor condition is changed, then that suggests an evolution of construction and wear characteristics. Gen 3 PCCB don't have the indicators, as far as I know.

Combine previous gen rotor tech with your pad theory and lack of cooling, and you get the very dissimilar results for M's system vs GM's or Porsche's.
My understanding is that Brembo incorporates wear indicators by customer request. BMW and Merc have requested it, where Porsche and Bugatti have not.



Technically, all CCB rotors should be measured by weight or by the Proceq system also shown in this thread. The wear indicators are like a dummy light to further inspect the rotors - perhaps why VAG does not specify them. Proceq is nice because you don't have to remove the disc.

If you look at the Gen 2 PCCB in your photo, you can see that the disc face is very different to the Gen 4 - you can physically see little grains from the carbon fiber reinforcement, rather than the glass-like, crazed face of the newer stuff.

My understanding was that Gen 2 + wear indicators = Gen 3, but I could be wrong there. Gen 4 is the new style where you cannot see grains, but instead a glass like surface with crazing/stress relief cracks. The M CCB is definitely Gen 4 construction.
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      10-30-2020, 04:22 PM   #30
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Originally Posted by 4play View Post
Technically, all CCB rotors should be measured by weight or by the Proceq system also shown in this thread. The wear indicators are like a dummy light to further inspect the rotors - perhaps why VAG does not specify them. Proceq is nice because you don't have to remove the disc.

If you look at the Gen 2 PCCB in your photo, you can see that the disc face is very different to the Gen 4 - you can physically see little grains from the carbon fiber reinforcement, rather than the glass-like, crazed face of the newer stuff.

My understanding was that Gen 2 + wear indicators = Gen 3, but I could be wrong there. Gen 4 is the new style where you cannot see grains, but instead a glass like surface with crazing/stress relief cracks. The M CCB is definitely Gen 4 construction.
The wear indicator was a gen 2 development. Via rennlist back in the day on the gen 1 to gen 2 differences.

The new design is supposed to be better for 2 main reasons. The different drilling of the holes helps it cool better/faster and I think they are a bit thinner as well...The new ones also have a different fiber "size". If you compare them side by side,youll see how the "grain" is different. The new ones also have small circles that let you know how they have been used. It looks like a plug on the rotor itself...

991 = gen 3, no wear indicators. Check out the bit about pads on the GT cars.

Now in their third generation of development, the PCCB rotors are made of silicon carbide reinforced with carbon-fiber chips. They are slightly larger than the standard cast-iron units at 16.1 by 1.4 inches in front and 15.4 by 1.3 inches in the rear, and are clamped by massive fixed aluminum calipers (six pistons front and four pistons rear). And in the case of the GT3 RS (as well as the GT3 and Cayman GT4), the brakes also come with more aggressive Pagid brake pads; the whole system is utterly confidence inspiring and indefatigable.



I've run into a few of these Surface Transforms systems and rotor swaps. Info from them on the varying ccb construction techniques and why their product is better equipped for track duties --

How do you make a Carbon Ceramic disc?

The Carbon Ceramic brakes fitted as standard on many high performance vehicles are constructed in one of two ways – either a core of ceramic material reinforced with chopped carbon fibre with an additional ceramic layer on the friction surface or simply the core of ceramic material with chopped carbon fibre and no outer friction layer. Surface Transforms use a different process, utilising continuous carbon fibre to produce a carbon-carbon which is then infilitrated with carbon silicide before being machined to suit the application

What are ‘next-generation’ Carbon Ceramic brakes?

Whilst the carbon-ceramic discs you find on production road cars use discontinuous (chopped) carbon fibre, ST’s next-generation technology interweaves continuous carbon fibre to form a 3D multi-directional matrix which has significant benefits over traditional carbon-ceramic products:

Stronger and more durable product - lower weight construction
3 x heat conductivity - reduces brake temperature and improves performance
Can be refurbished when traditional product is thrown away

These attributes make ST’s product ideally suited for the demanding nature of track days, providing ultimate performance for drivers that want to take their high performance road car on track and drive home afterwards.

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      10-30-2020, 04:34 PM   #31
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Originally Posted by JLS_397K View Post
Can anyone chime in as to why others that run the BMW CCB just end up suggesting that one should replace the pads themselves before half life and not to worry about rotors until later on?

And has anyone seen Proceq (or Carboteq) CCB wear tester? it utilize the three positions around the rotor hat apparently. check out the link below. Its on youtube
There was a forum member who owned one of these tools. Believe he made a run at making the ccb's work long-term on track, but bounced after replacing the discs once or twice.

Not worrying about the rotors until later on was going to be my approach. Even looked into disc refurbishment options like https://www.rebrake.de/preise/?lang=en

Figured if I could do refurbishment every other season or so, not too bad. But my interest in ccb was in less ongoing maintenance and concern, not more. After the wear indicators go to hell like mine, your options are rotors on and off for weighing on a regular basis, or the Proceq tool for crazy $. At that point you begin wondering why options like the AP Racing kits that run GT3 endurance races won't suffice after all.
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      10-30-2020, 05:15 PM   #32
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To bad that even with a proper tool to identify wear on CCBs, one still just ends up switching over to iron.

At the end of the day, everyone is going to switch to iron rotors if they continue to track the GTS. For sprint runs and the occasional canyon run, the CCB will last and offer that initial unsprung weight savings/bite. Of course the garage queens still got that fresh surface look.

Either you are going to keep the car and roll with the punches, pay what is financially best for you or move to another car.

Not like you are going to find a lightly used M4 GT4 on Craiglist.
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      10-30-2020, 06:20 PM   #33
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Originally Posted by SYT_Shadow View Post
If you're a newbie then track it with CCBs, however, I suggest that if you like it and start going more then please move to a BBK so you don't ruin your CCBs. They will be needed for resale eventually

The AP RadiCals are overrated. They are off my car and the rears are for sale if someone wants them.
Alcon's new kit is significantly improved vs the RadiCals but this is not a very difficult achievement.

So far I've had all three on my car and:
PFC ~= Alcon
PFC > AP RadiCal
Alcon > AP Radical
Your PFC Z54/AP 9449 setup shifted the brake bias ~10% to the rear (assuming same pad compounds F & R) vs. the AP 9668/9449 setup. You didn’t run the full AP kit so just be careful with your comparisons when saying PFC > AP and Alcon > AP.
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      12-08-2020, 01:19 PM   #34
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Dredging this back up again-

Up above people said you could do a direct replacement of the CCB rotors with M2C iron.

I am assuming you don't need to change out the calipers since I think the rotors are the same diameter, is this true?

Has anyone done this, how much did it cost, and what pads are you using?

Seems like something I could even do myself.
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      12-08-2020, 01:51 PM   #35
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Originally Posted by h_bakken View Post
Dredging this back up again-

Up above people said you could do a direct replacement of the CCB rotors with M2C iron.

I am assuming you don't need to change out the calipers since I think the rotors are the same diameter, is this true?

Has anyone done this, how much did it cost, and what pads are you using?

Seems like something I could even do myself.
You just need to buy front/rear M2C rotors. Bimmerworld offers a kit for front rotors and for rear rotors, but you can find them for a bit cheaper if you shop around. Total rotor cost should be around $1200. It's a direct bolt-on.

For pads, anything that "fits" M2C will work. For street use, something like Ferodo DS2500, track use, DS1.11.
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      12-08-2020, 02:09 PM   #36
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I have the 9668/9449 set up on my car as well and it is fantastic. Pad swaps between street and track pads take zero time at all. It takes longer to get the car in the air and get the wheels off than it does to actually swap the pads. However, I don't think I'd do the 9668 front again and would probably go for the 9660 front. The big pad is absolute overkill and limits wheel choices more than the thin pad version. I'm not saying the 9668 set up is bad and I'm all about overkill but I just don't think it's necessary at all for anything like a run of the mill track day, even with a really capable driver and no added cooling for a 30 minute session.

I run ds2500's on the street. They squeal a bit but it's nothing ridiculous. I daily the car still with no issues as far as nvh goes. I also run ds1.11's in the front and ds uno's out back. I've got a set of 3.12's on the way and have heard nothing but good things about them. I'm not a huge fan of the release characteristics of my current track pad set up but it's nothing major and can most likely be overcome by a better driver than myself.
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      12-09-2020, 03:59 PM   #37
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Quote:
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Originally Posted by h_bakken View Post
Dredging this back up again-

Up above people said you could do a direct replacement of the CCB rotors with M2C iron.

I am assuming you don't need to change out the calipers since I think the rotors are the same diameter, is this true?

Has anyone done this, how much did it cost, and what pads are you using?

Seems like something I could even do myself.
You just need to buy front/rear M2C rotors. Bimmerworld offers a kit for front rotors and for rear rotors, but you can find them for a bit cheaper if you shop around. Total rotor cost should be around $1200. It's a direct bolt-on.

For pads, anything that "fits" M2C will work. For street use, something like Ferodo DS2500, track use, DS1.11.
So no issues that the front M2C rotor is 40mm smaller in diameter?
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      12-09-2020, 06:45 PM   #38
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So no issues that the front M2C rotor is 40mm smaller in diameter?
The interchangeable front and rear M2C rotors are the same size as the M3/4 CCB - 400mm front / 380mm rear.

The old (pre-facelift, non S55, non Competition) M2 had 380mm front / 370mm rear discs from the base M3/M4. Those are obviously not interchangeable.
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      12-10-2020, 10:00 AM   #39
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Originally Posted by h_bakken View Post
So no issues that the front M2C rotor is 40mm smaller in diameter?
The interchangeable front and rear M2C rotors are the same size as the M3/4 CCB - 400mm front / 380mm rear.

The old (pre-facelift, non S55, non Competition) M2 had 380mm front / 370mm rear discs from the base M3/M4. Those are obviously not interchangeable.
Thank you!
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      12-10-2020, 11:34 AM   #40
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Originally Posted by Gomeler View Post
Less expensive option is the M2C rotor + a track-oriented pad for the CCB/M2C caliper. Requires a 19" up front, so I guess run something like 19x10/18x11? Can't comment on that.

Buy once, cry once. AP9668/AP9449 + track-oriented pad(Carbotech XP12/Hawk DTC-70 have worked well for me. Think people also like the PFC-08?). That enables the use of 18" wheels, I highly recommend 18x11 square via Apex EC-7 wheels. Been fantastic for tire wear with the ability to rotate corners.
What part number (Carbotech) do you use for the AP application? I have the same set up and use the Ferodo DS1.11. Could also tell me the source? Thanks.
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      12-10-2020, 01:16 PM   #41
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Does anyone know the part numbers for the M4 GT4 brakes? I'm assuming that while they are probably available directly from BMW, they are sourced from one of the well known brake suppliers.

I'm thinking about going this route when I update early next year for track day use.
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      12-10-2020, 02:00 PM   #42
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Originally Posted by Secret Chimp View Post
Does anyone know the part numbers for the M4 GT4 brakes? I'm assuming that while they are probably available directly from BMW, they are sourced from one of the well known brake suppliers.

I'm thinking about going this route when I update early next year for track day use.
Front calipers are AP Racing CP6276, rear calipers are AP Racing CP6480. I believe you need GT4 brackets to fit them as well.

Front brake pads are Pagid RSL1 material, pad shape is RCP177. Rear brake pads are Pagid RS19 material, pad shape is RCP002.

Brake rotor rings have 2 different variants - sprint race (lighter and less durable) and endurance race (heavier but stouter).

https://www.realoem.com/bmw/enUS/sho...diagId=34_2556

https://www.realoem.com/bmw/enUS/sho...diagId=34_2574

Makes much more sense to just source AP Racing calipers/pads/rotors yourself rather than pay massively inflated BMW Motorsport prices. Because it's a race setup, the hats, mounting pins, and rotor rings are all sold separately, so you would need to buy them and assemble them.

Quickly priced it out - none of these prices include any tax or shipping:

Calipers: $8200
Rotor Rings: $2500
Rotor Hats: $1600
Best guess on mounting hardware: $400
Pads: $3800

Full setup (and doesn't have the brake ducting it needs to work properly): $16,500

Add in the ~$10k for the GT4 splitter and bumper ducting + brake backing plates and you're at $25k+ to solve a problem that can be solved for 1/5 the cost. That's a big premium just to say you have "race grade" parts.

Honestly, with proper cooling and more aggressive (RSC1) pads, there is nothing wrong with the OEM setup. The problem is that the OEM setup has no provision for brake cooling whatsoever, so the pads overheat and oxidize the discs very quickly.
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      12-10-2020, 02:22 PM   #43
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Originally Posted by Secret Chimp View Post
Does anyone know the part numbers for the M4 GT4 brakes? I'm assuming that while they are probably available directly from BMW, they are sourced from one of the well known brake suppliers.

I'm thinking about going this route when I update early next year for track day use.
The M4 GT4 uses AP Racing brakes. You can see the RealOEM pages here: Front, Rear.

The front caliper looks to be a CP6277 and the rear a CP6480. The pads on them are both larger surface area-wise than the Essex 6998/9449/9451 kits, and for the front setup, the thickness of the pads is also larger (30mm vs 25mm). The AP Racing Catalog has all the info you need to compare.
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      12-10-2020, 03:18 PM   #44
Secret Chimp
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Quote:
Originally Posted by 4play View Post

Makes much more sense to just source AP Racing calipers/pads/rotors yourself rather than pay massively inflated BMW Motorsport prices. Because it's a race setup, the hats, mounting pins, and rotor rings are all sold separately, so you would need to buy them and assemble them.

Quickly priced it out - none of these prices include any tax or shipping:

Calipers: $8200
Rotor Rings: $2500
Rotor Hats: $1600
Best guess on mounting hardware: $400
Pads: $3800

Full setup (and doesn't have the brake ducting it needs to work properly): $16,500

Add in the ~$10k for the GT4 splitter and bumper ducting + brake backing plates and you're at $25k+ to solve a problem that can be solved for 1/5 the cost. That's a big premium just to say you have "race grade" parts.

Honestly, with proper cooling and more aggressive (RSC1) pads, there is nothing wrong with the OEM setup. The problem is that the OEM setup has no provision for brake cooling whatsoever, so the pads overheat and oxidize the discs very quickly.
Thanks for this. Changing from CCB's to iron via this route feels a bit like a $16k solution to a $17k problem, doesn't it? Those prices you quoted are all OEM via BMW prices, right?

Do you have any more info on how folks are adding cooling to the CCB's? I saw someone with a Porsche air deflecting paddle zip tied to a suspension part. It didn't look like it would be very effective, but looks can be deceiving.
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