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      08-19-2020, 11:57 PM   #1
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Brake upgrade suggestions needed!

Howdy,

I've run PFC08 pads for a while on the stock calipers and they've held up well but performance drops off noticeably after about 5 laps

I'm looking for more stopping power and more endurance than the OEM units can provide.

What are you running on track? Stoptech's? AP's? Let me know what you think I should run.

Thanks!

Update: For an OG M2. And yes I accidentally posted this in Track section rather than Brakes, oops.
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      08-20-2020, 12:16 AM   #2
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I suggest trying PFC 11’s and the Porsche GT3 cooling mods before switching out the brakes completely. You’ll easily get 5 laps out of that setup.
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      08-20-2020, 12:44 AM   #3
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Quote:
Originally Posted by ZM2 View Post
I suggest trying PFC 11ís and the Porsche GT3 cooling mods before switching out the brakes completely. Youíll easily get 5 laps out of that setup.
Good call and easy to implement. My 08's are probably a couple of events away from needing replacement and I've been interested in the cooling mods, just haven't got round to doing them.

BUT if you are upgrading the caliper what are you going with?
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      08-20-2020, 05:17 AM   #4
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AP’s are the best and what I went with. I’m not familiar with the cost or performance of any intermediate setups.
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      08-20-2020, 06:01 AM   #5
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Quote:
Originally Posted by ZM2 View Post
APís are the best and what I went with. Iím not familiar with the cost or performance of any intermediate setups.
+1 AP's are the best.

Did you go front and rear or just fronts?
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      08-20-2020, 08:21 AM   #6
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Originally Posted by F87source View Post
+1 AP's are the best.

Did you go front and rear or just fronts?
Just fronts for now since thatís where the overheating issues exist. It moves the brake bias slightly to the front, but they have pretty awesome consistency no matter how hard you push, especially with Ferodo DS3.12.

Waiting for my rear calipers to die before I get rear APís. If I had to do it all over again, the blue brakes would have come off on Day 1 and APís would have gone on all four corners.
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      08-20-2020, 10:25 AM   #7
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Just curious, when you say the performance drops off significantly do you mean pedal feel or deceleration?

I ask because I also have stock blue brakes with PFC08 and Castrol SRF fluid, and I do notice the pedal getting longer after 10min or so, but the stopping performance is still very good. I'd go as far as saying that stopping distance when just warm to 20min into the session is still the same. Pedal definitely feels more spongy and has to travel more, but I compensate by stomping on it like there is a tarantula on the floor.
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      08-20-2020, 10:49 AM   #8
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PFC 08s should be sufficient and shouldn't really "drop off" although I'm not sure exactly how they are dropping off for you. If they are, likely cooling ducts are the way to go. There are a number of threads on here where people have done that and it can be done very inexpensively.

I did go with the AP 9660's though. They will allow you to fit 18" wheels, don't change color, and don't tire out. Their customer service is also awesome. If you want to go aftermarket, go straight to AP.
I do wish PFC made their compounds in the shape for the APs because I am a huge fan of their pads. Nothing wrong with Ferodo though.
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      08-20-2020, 11:55 AM   #9
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Quote:
Originally Posted by 5.M0NSTER View Post
Just curious, when you say the performance drops off significantly do you mean pedal feel or deceleration?

I ask because I also have stock blue brakes with PFC08 and Castrol SRF fluid, and I do notice the pedal getting longer after 10min or so, but the stopping performance is still very good. I'd go as far as saying that stopping distance when just warm to 20min into the session is still the same. Pedal definitely feels more spongy and has to travel more, but I compensate by stomping on it like there is a tarantula on the floor.
I experience the same thing as you - way more pedal travel as they heat up, but I find I have to readjust on braking markers.. I'm just not getting the same stopping power. I bleed/flush regularly so I know it's not the fluid.

Then again, maybe i just need to do as you do and STOMP on that thing harder.
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      08-20-2020, 11:58 AM   #10
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Quote:
Originally Posted by JoeP View Post
PFC 08s should be sufficient and shouldn't really "drop off" although I'm not sure exactly how they are dropping off for you. If they are, likely cooling ducts are the way to go. There are a number of threads on here where people have done that and it can be done very inexpensively.

I did go with the AP 9660's though. They will allow you to fit 18" wheels, don't change color, and don't tire out. Their customer service is also awesome. If you want to go aftermarket, go straight to AP.
I do wish PFC made their compounds in the shape for the APs because I am a huge fan of their pads. Nothing wrong with Ferodo though.
I think cooling will make a huge difference. I just need to find the time to get the parts and do the work. Nice to know AP's are the way to go though if I give up on all that and just revert to the wallet. Thanks
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      08-20-2020, 12:48 PM   #11
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Quote:
Originally Posted by dcmac View Post
I experience the same thing as you - way more pedal travel as they heat up, but I find I have to readjust on braking markers.. I'm just not getting the same stopping power. I bleed/flush regularly so I know it's not the fluid.

Then again, maybe i just need to do as you do and STOMP on that thing harder.
Ok, got ya. SS lines might help too, but they are a double edge sword depending on manufactures. I had 2 year old SS line rapure on me before. Unacceptable.

I hear you, the pedal feel is not confidence inspiring, and I think I just programmed it in my brain that once hot the first 1.5-2" of pedal travel don't do anything. But my brake points get progressively later. I aim to brake when I see God. And it takes me time to work up the courage to do so. Because at some point you just hope the brakes are still there
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      08-20-2020, 01:18 PM   #12
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The PFC 08 doesn’t have much bite to begin with and looses some when the pad gets hot. Couple that with the fluid getting toasty and you experience exactly what you guys are describing.

Changing to PFC 11’s and adding the Porsche GT3 air deflectors with allow you to run hard and not get the same feeling until 20min into a session.

Last edited by ZM2; 08-20-2020 at 01:24 PM..
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      08-20-2020, 02:04 PM   #13
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Quote:
Originally Posted by dcmac View Post
I experience the same thing as you - way more pedal travel as they heat up, but I find I have to readjust on braking markers.. I'm just not getting the same stopping power. I bleed/flush regularly so I know it's not the fluid.

Then again, maybe i just need to do as you do and STOMP on that thing harder.
Braking harder, later, and for a shorter time period will definitely help. That plus the brake ducting. I have 2 BNIB kits that are about to go up for sale if you want one of them.

I think it's both of these pieces:
https://www.ecstuning.com/b-genuine-...99733148702kt/
https://www.ecstuning.com/b-genuine-...99734148392kt/
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      08-20-2020, 10:50 PM   #14
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Quote:
Originally Posted by kpaso View Post
Braking harder, later, and for a shorter time period will definitely help. That plus the brake ducting. I have 2 BNIB kits that are about to go up for sale if you want one of them.

I think it's both of these pieces:
https://www.ecstuning.com/b-genuine-...99733148702kt/
https://www.ecstuning.com/b-genuine-...99734148392kt/
Thanks. So these literally clip to the lower control arm? Suspension arm? Is there a hose that runs through to the dust shield (which I assume would need to be modified to accept the hose?) or is it just a plastic piece that redirects air in a general fashion rather than directly through a hose?
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      08-20-2020, 11:02 PM   #15
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Quote:
Originally Posted by dcmac View Post
Thanks. So these literally clip to the lower control arm? Suspension arm? Is there a hose that runs through to the dust shield (which I assume would need to be modified to accept the hose?) or is it just a plastic piece that redirects air in a general fashion rather than directly through a hose?
I think ZM2 posts about it in this thread: https://f87.bimmerpost.com/forums/sh....php?t=1366784

Maybe he can chime in if that's the wrong one.
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      08-21-2020, 05:08 AM   #16
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Quote:
Originally Posted by dcmac View Post
I think cooling will make a huge difference. I just need to find the time to get the parts and do the work. Nice to know AP's are the way to go though if I give up on all that and just revert to the wallet. Thanks
I have similar complaints to you.

I did the cooling mod and it improves the brakes a lot. I did this after ordering an AP set and im kinda doubting whether I need the AP set or not.

I used backing plates from 55parts.de (not on their site now for some reason)
and 3D printed scoops I made myself.

I think the scoop/hose combo is better than the diverter scoops. The diverter scoops dont blow air straight onto/into the disk and therefore are less efficient.

BTW here is my solution for the rear (proto at this stage)
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      08-21-2020, 05:22 AM   #17
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You’re not supposed to blow air straight onto the disc. It leads to large temp differences and premature cracking and pad wear. This is the main reason I haven’t done any of the backing solutions for the M2, that and I’ve seen carbon backing plates catch on fire.

My deflectors direct air into the hat.

I think the some cooling on the M2 is good whether you have APs or not, since the airflow is so bad on our cars. The M2C at least has some air flowing into the wheel well, which helps.

If I was pushing really hard in a 30-45min session I’d get a little fade in the front AP’s, but it was pad fade from the DS1.11, which kind of reminds me of a PFC 08 (which I never cared for much). Once the DS3.12 came out, no fade ever and super consistent and similar feel to a PFC 11.

Also getting rear APs maybe would have negated me needing the GT3 deflectors, but again, the air flow on the OG M2 is terrible, so it cant hurt. They also don’t overcool the disc surface in winter time, which many of the hose/backing plate kits do making it an issue in cold weather daily driving.

Last edited by ZM2; 08-21-2020 at 05:41 AM..
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      08-21-2020, 05:53 AM   #18
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Quote:
Originally Posted by ZM2 View Post
You’re not supposed to blow air straight onto the disc. It leads to large temp differences and premature cracking and pad wear. This is the main reason I haven’t done any of the backing solutions for the M2, that and I’ve seen carbon backing plates catch on fire.


Also getting rear APs maybe would have negated me needing the GT3 deflectors, but again, the air flow on the OG M2 is terrible, so it cant hurt. They also don’t overcool the disc surface in winter time, which many of the hose/backing plate kits do making it an issue in cold weather daily driving.
So do the "good" backing plates. Never heard of them catching fire but now that you mention it I think this happened to the Schirmer M2C at my last trackday (had a little off and as I passed under the red flag saw flames in the wheel well/barel).

I also think the differential cooling is not as big an issue as ppl seem to think it is. A GT2 RS comes with rear under arm funnels that blow straight onto the disk face, I think Porsche know what they are doing.

Is it more efficient to blow in the center? probably, but without empirical data we are just comparing educated guesses. There are also so many variables to account for that annecdotal evidence should be taken with a large pinch of salt.

Overcooling is such a minor issue in my opinion. Removing the rear scoops is as easy as cutting 3 zipties and takes 5min. The front intake scoops can be covered with duct tape in minutes and then they dont flow or cool the brakes.

I did this at my last trackday in order to be able to bed in my new pads.

EDIT: seem Porsche has been doing this for quite a while http://forums.pelicanparts.com/porsc...ing-ducts.html
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Last edited by Megator; 08-21-2020 at 06:07 AM..
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      08-21-2020, 06:16 AM   #19
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Blowing on the rear disc is fine. The front is where we see big temps.

It’s prob not a big deal bc most guys aren’t pushing their cars hard enough to create big temp differential issues, and why most guys here don’t have problems with hose setups.

But if you look at proper backing plate setups on race cars, they’re funneled to the hat, not the disc.

And I’d never put them on my street car bc of the fire hazard. If you keep your car between the lines on track like you do on the street, no big deal. If you explore track limits with them, you’re asking for trouble.

Last edited by ZM2; 08-21-2020 at 06:24 AM..
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      08-21-2020, 06:44 AM   #20
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Quote:
Originally Posted by ZM2 View Post
Blowing on the rear disc is fine. The front is where we see big temps.

Itís prob not a big deal bc most guys arenít pushing their cars hard enough to create big temp differential issues, and why most guys here donít have problems with hose setups.

But if you look at proper backing plate setups on race cars, theyíre funneled to the hat, not the disc.

And Iíd never put them on my street car bc of the fire hazard. If you keep your car between the lines on track like you do on the street, no big deal. If you explore track limits with them, youíre asking for trouble.
We are not disagreeing

Sadly none of the metal ones fit the bill of blowing into the "hat". Even this one is only like 70-80% OK.

I was going to make my own CF ones but the space into the hat iis so tight this is almost impossible. Maybe with the AP disks this is less of an issue as the hat seems bigger.

This time next week I should have some temp data and I like to color outside the lines
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      08-26-2020, 02:40 AM   #21
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Quote:
Originally Posted by 5.M0NSTER View Post
Just curious, when you say the performance drops off significantly do you mean pedal feel or deceleration?

I ask because I also have stock blue brakes with PFC08 and Castrol SRF fluid, and I do notice the pedal getting longer after 10min or so, but the stopping performance is still very good. I'd go as far as saying that stopping distance when just warm to 20min into the session is still the same. Pedal definitely feels more spongy and has to travel more, but I compensate by stomping on it like there is a tarantula on the floor.
Regarding the pedal feel - do you get inconsistent pedal feel? I usually get the normal progression of the pedal becoming spongey after a few laps, but everyone once in a while the pedal will be a maximum firm and the bite point will be 1cm from the top (whereas usually it's halfway to the floor), and then the turn after that it will go back to be it's usually spongey self.

I can't really figure this one out, so usually I test the brakes just a bit before I really stomp on them.
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      08-26-2020, 05:17 AM   #22
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Quote:
Originally Posted by eeyang92 View Post
Regarding the pedal feel - do you get inconsistent pedal feel? I usually get the normal progression of the pedal becoming spongey after a few laps, but everyone once in a while the pedal will be a maximum firm and the bite point will be 1cm from the top (whereas usually it's halfway to the floor), and then the turn after that it will go back to be it's usually spongey self.

I can't really figure this one out, so usually I test the brakes just a bit before I really stomp on them.
Look up "knock back" or "pad nock back". If the feeling corelates to having just done a high G corner then this is likely what is happening.

I notice it on my brakes from time to time.

https://nasaspeed.news/tech/brakes/p...o-do-about-it/
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