Prep Stock Brakes for Track Use?

Other than switching to Motul 660 brake fluid the brake system on e92 M3 DCT comp is stock. It has 77k miles and has never been to the track. What is recommended before my first track day with the car? The track consists of 5x 30min sessions on a 3.56-mile track with 19 turns and a 1,850-foot straightaway. I plan to take the wheels off and confirm the pads have plenty of life left.

Should I:
1. Confirm the rotor thickness front and back? (Is there a recommended min thickness for this?)
2. Grease any brake components (slides/pins)?
3. Switch to bronze bushings?
4. Anything else?

The car has 80% life left on Pirelli P zeros in the front, brand new 275 width Continental ExtremeContant Sport 02 tire on back, all mounted on 359 comp wheels.

I'm easing into track duty with the car. Outside of brakes the car just got new rod bearings, DCT fluid, rear diff fluid, injectors, spark plugs, engine air filter, VANOs cover, valve covers, alignment, and recent throttle actuators.

30 minutes sessions are long. Which brake pads do you have? I wouldn't run a full session on non track pads. Also, make sure you do a full brake fluid flush, not just bleed.

I've tracked my car with only hawk DTC60 pads and hawk fluid and it held up great for 20 minutes sessions. Bone stock otherwise. Car is a blast to drive, even in stock form. Have fun!

BigTee wrote

30 minutes sessions are long. Which brake pads do you have? I wouldn't run a full session on non track pads. Also, make sure you do a full brake fluid flush, not just bleed.

I've tracked my car with only hawk DTC60 pads and hawk fluid and it held up great for 20 minutes sessions. Bone stock otherwise. Car is a blast to drive, even in stock form. Have fun!

Thanks, my pads are stock close to brand new. What will I notice using pads for 30min sessions?

I’ll confirm the brake system was flushed and not just bleed. I believe all the stock fluid was replaced with 660.

Agreed here. 30min sessions are long and that’s a pretty long straight on the track you’ll be driving. That means you will be going pretty fast at the end and will be asking a lot from the brakes. Highly recommend putting some track oriented pads in and you should be fine.

All you need is fluid and good track pads, the rest is just nice-to-have.

Make sure your brake hoses are in good shape with no cracking.

TooManyAxles wrote

Thanks, my pads are stock close to brand new. What will I notice using pads for 30min sessions?

I’ll confirm the brake system was flushed and not just bleed. I believe all the stock fluid was replaced with 660.

They might melt, they might completely wear out that day. Its hard to tell since BMW has a few variants of pads.

BigTee wrote

They might melt, they might completely wear out that day. Its hard to tell since BMW has a few variants of pads.

Is it useful to pull the pads to determine which variant I have?

pirategenes wrote

Agreed here. 30min sessions are long and that’s a pretty long straight on the track you’ll be driving. That means you will be going pretty fast at the end and will be asking a lot from the brakes. Highly recommend putting some track oriented pads in and you should be fine.

I'm a track novice, what pads would you recommend? The car will be driven 2hr to the track and back.

amg6975 wrote

All you need is fluid and good track pads, the rest is just nice-to-have.

Make sure your brake hoses are in good shape with no cracking.

Good idea, thank you. Are there pads would you recommend for a track novice? The car will be driven 2hr to the track and back.

TooManyAxles wrote

I'm a track novice, what pads would you recommend? The car will be driven 2hr to the track and back.

I think for this purpose the Ferodo DS2500 is a good option and can be used on both street and track. You can get these at FCP Euro, which gives you lifetime replacement.

Front:
https://www.fcpeuro.com/products/bmw-performance-brake-pad-set-ferodo-racing-34116794917

Rear:
https://www.fcpeuro.com/products/bmw-performance-brake-pad-set-ferodo-racing-fcp1672h

I used to take mine to VIR with just an SRF flush and PFC-08 pads. Tires were RE-71Rs. Everything else was stock and i had no issues with fade, etc. Rotors get worn fairly quickly and the pads squeal like crazy when cold, but the brakes inspired confidence. I definitely felt like i had to drive for a few good minutes after the sessions to cool things down as well.

TooManyAxles wrote

I'm a track novice, what pads would you recommend? The car will be driven 2hr to the track and back.

Do you anticipate doing more events this year? Can you swap pads for events? If so, there are a slew of decent track pads you can use. I'm currently using Hawk DTC60's and they work well, but are extremely noisy. I swap to stock BMW pads for normal car use.

If you have to use one pad, look into the PowerStop Trackday pads. They are cheap and will work fine for you.

https://www.powerstop.com/product/power-stop-track-day-brake-pads/

TooManyAxles wrote

Good idea, thank you. Are there pads would you recommend for a track novice? The car will be driven 2hr to the track and back.

Since I sell them, GLOC R10 or R12 would do great, but any mid friction track pad will also work. R16 or R18, or other high friction pad once you gain speed and confidence.

Being this will be my first track day can I just brake early after the long straight? How long /how many sessions do track specific pads last? I’m not sure if it’s worth buying track specific pads if I plan to upgrade to a BBK at some point.

TooManyAxles wrote

Being this will be my first track day can I just brake early after the long straight? How long /how many sessions do track specific pads last? I’m not sure if it’s worth buying track specific pads if I plan to upgrade to a BBK at some point.

I think a good track pad is an essential safety item. I would think twice about jumping in and instructing in an E9x with stock pads without making sure they are above 50% before every session. You could easily roast a set of OEM pads in a day.

As a novice a good set of track pads will last seasons, not sessions. I'd expect a GLOC R10 or R12 to last maybe 40-50x 20 minute sessions. As you gain speed the wear rate will go up, of course.

You CAN run stock pads, but I really think you will enjoy the day better swapping on dedicated track pads (which you can drive home with, just be careful).

If you do run the stock pads, you will notice they become softer and the pedal will feel like sponge. You will be fine for the first couple laps of the session, but once the pads heat up and fade, they will not work as well. If you are having fun, it will limit your fun because you will need to pull off and end your session early. Again, you can run the stock pads, since you said they were newer, just really pay attention to pedal feel every corner, and pull off once they soften. (or swap on a set of GLOC or PFC 11 and never worry about it )

How difficult will it be for you to swap brake pads before and after track days? It is inconvenient, but it really does make the track day experience a LOT better.

TooManyAxles wrote

I’m not sure if it’s worth buying track specific pads if I plan to upgrade to a BBK at some point.

I would actually argue the opposite. I believe the stock braking system, with high-temp fluid and track-dedicated pads, is plenty adequate for any novice to low-intermediate HPDE driver. I think a BBK is only necessary when your lap times get fast enough to hit the limits of the stock calipers, but just my opinion.

As a beginner, you'll probably be fine with stock pads and just higher temp fluid, as I'm guessing if you've never been on track before, you won't be braking hard enough to roast your pads in one day, and you're on max performance tires, not 200tw. Hard to know your skill level and comfort with performance driving, so you may end up working the brakes pretty hard in the later sessions, but generally speaking, for your first day, you should be fine. 30 min sessions are definitely long, as others have mentioned, so you might need a cool down lap after 5-6 laps if you're getting near the threshold, but I'm guessing you will be fine with just the higher temp fluid.
No need to grease slide pins as the manual doesn't call for it, and bronze bushings aren't needed for your first day or season.

And you can definitely go a long way with upgraded track pads with stock brakes before you ever need to consider a BBK. Swapping pads isn't too bad once you've done the procedure a couple of times.

Thank you, is there anything I can do to remove the long travel before bite and spongy/sloppy feel of the brake pedal? This is what I feel now with nearly new stock pads and rotors and 660 fluid while driving on the street. Will switching to performance pads help this?

TooManyAxles wrote

Thank you, is there anything I can do to remove the long travel before bite and spongy/sloppy feel of the brake pedal? This is what I feel now with nearly new stock pads and rotors and 660 fluid while driving on the street. Will switching to performance pads help this?

Your car will probably need a DSC calibration. Need ISTA or protools to do something like that.

If you JUST had your brakes flushed, the pedal will get slightly stiffer after a few hard stops.

VtecforV8 wrote

I used to take mine to VIR with just an SRF flush and PFC-08 pads. Tires were RE-71Rs. Everything else was stock and i had no issues with fade, etc. Rotors get worn fairly quickly and the pads squeal like crazy when cold, but the brakes inspired confidence. I definitely felt like i had to drive for a few good minutes after the sessions to cool things down as well.

^ This above is exactly right. TooManyAxles Use PFC-08 pads (or PFC-12), MOTUL 660 or Castrol SRF plus, install cool air ducting as detailed below and use the cool down lap(s) before pitting. Also see the other information below and attachment.

TooManyAxles wrote

Thank you, is there anything I can do to remove the long travel before bite and spongy/sloppy feel of the brake pedal? This is what I feel now with nearly new stock pads and rotors and 660 fluid while driving on the street. Will switching to performance pads help this?

Change your shoes to something with a thinner and firmer sole and/or install steel braided brake lines.
.

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Getting cool air to the stock brakes goes a helluva' long way to helping the brakes (resist pad fade and fluid fade) and brake fluid last for longer sessions especially at higher speed tracks.
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https://trucranemotorsports.com/products/airtec-motorsport-brake-duct-kit-bmw-m3-e90-e92-e93-s65
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https://www.bimmerworld.com/Brakes/Performance-Components/E9X-M3-and-1M-Carbon-Fiber-Brake-Cooling-Plates-Pair.html
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TooManyAxles wrote

Thank you, is there anything I can do to remove the long travel before bite and spongy/sloppy feel of the brake pedal? This is what I feel now with nearly new stock pads and rotors and 660 fluid while driving on the street. Will switching to performance pads help this?

Yes you will need to run the full ABS fluid cycle thing. (also yes, different pads will have different pedal feels)

But if you can't: How did you (or your shop) bleed the brakes? Pressure/vacuum bleeders don't quite get it all (without running the ABS cycle). The 2-person method, where one person sits in the car and pumps while the other opens and closes the fitting, does a much better job. I noticed a big difference in pedal feel between the two methods.

Note: I had to do the computer bleed several times to get it fully back to "normal." Going out on a wet street and [safely] engaging ABS helps loosen up some of the stuck bubbles as well.

My theory is the computer bleed is made to do an ok job quickly so it rattles up the fluid too much and causes micro bubbles that will reform into larger bubbles over time. My sure-fire method:

Pressure Bleed, Computer Bleed, then go out and engage ABS. Let it sit for at least a couple hours and repeat until it's good.

I've had it take three of those cycles to be back to acceptable, and can still get tiny bubbles doing flushes for like two years, particularly from the rears.

Also, everyone should throw SRF in the trash. It has great properties but feels like crap in our braking systems for whatever reason. Motul or ATE Super 200.