Brake Pads: PFC 08's are high adventure...anyone tried 331 332?

[eacmen]

I've found that bedding track pads in on the street to be a waste of time if you're driving on them to get to the track. By the time I arrive, the transfer layer seems to be completely gone from the rotors.

I do something similar to what eacmen mentioned to bed my pads in on the first session of the day. I'll also lightly left foot brake through long sweeping corners to help the pads get up to temp quicker. A combination of both these things means I can usually get the pads bedded in on the first lap, but that depends on traffic of course.

Just figured I'd put this out there since there's a bedding conversation going on.

On the topic of dragging the brakes to warm them up:

Its something I do as well. But was hesitant to recommend it toa beginner as other students around him may get confused with constant brake lights.

What I will say is that if you plan to do it then practice the left foot braking on the street before doing it on track. And tell your instructor what you plan to do. It is very effective but unless its a cold track you shouldn't be having any issues getting heat into the pfc08 pads just doing laps.

[fourmula1]

What was better? Initial bite? I didn't like the dull feel of the pagid yellows.

They are just consistent in all phases. Bite is always there, never bind, smooth release, don’t fade, last way longer.

[bigjae46]

No, unfortunately cant offer any comparison to those. I used pagid yellows for a while and these are infinitely better in my opinion.

What was better? Initial bite? I didn't like the dull feel of the pagid yellows.

[fourmula1]

Did you ever use PF01s or PF11s?

No, unfortunately cant offer any comparison to those. I used pagid yellows for a while and these are infinitely better in my opinion.

[bigjae46]

I track/race 331 and 332 and they work well for me. Stock calipers and rotors. Full aero/slicks etc.

Did you ever use PF01s or PF11s?

[fourmula1]

I track/race 331 and 332 and they work well for me. Stock calipers and rotors. Full aero/slicks etc.

[OldRanger]

PFC Europe website has a better compound comparison chart for just the endurance/sprint compounds. Their description:

• 331 is the next generation of PFC endurance material. Improved control with ABS, and gentle on discs.
• The 331 Carbon Metallic ® compound has been developed with higher initial bite than PFC’s renowned 08 endurance compound.
• The 331 has improved release, and continues to offer exceptional control and feel. It boasts low wear rate and exceptional disc conditioning.

Bimmerworld's product description: "We collaborated with PFC on this pad and it has been specifically engineered around BMW ABS systems where the torque slightly tapers back as temperature rises. Development focused on modulation and release to achieve superior braking, which is critical with an ABS car. Brake balance is shifted slightly rearward, but with fading torque at increased temperatures, this allows a driver to carry more speed to apex of a corner, and usually results in better trail braking and corner speed due to happier tires. These characteristics also benefit non-ABS cars where an eye on tire wear at peak braking will help extend tire life. The 331 is used on our pro cars typically in endurance environments (extremely long lifespan) where avoiding a pad change in the pits, as well as tire wear and tire performance over longer stints, is critical."

I wish PFC would quantify the y-axis, but I suppose that gives away competitive information

[heinzboehmer]

I've found that bedding track pads in on the street to be a waste of time if you're driving on them to get to the track. By the time I arrive, the transfer layer seems to be completely gone from the rotors.

I do something similar to what eacmen mentioned to bed my pads in on the first session of the day. I'll also lightly left foot brake through long sweeping corners to help the pads get up to temp quicker. A combination of both these things means I can usually get the pads bedded in on the first lap, but that depends on traffic of course.

Just figured I'd put this out there since there's a bedding conversation going on.

[OldRanger]

Not trying to treat you like a retard....but I have to ask. How did you bed the pads in?

To be constructive, the answer is something along these lines…here’s a link to PFC Pad Bedding: https://pfcbrakes.com/pad-bedding-procedure/. The caveat: my car is not a race car. I drive it to the track. So, I applied these concepts safely on public roads prior to track time. For the general public: none of the manufacturer-recommended bedding procedures (e.g PFC or Brembo) mention smoke as an indicator the procedure is complete.

For anyone still following hoping to hear more about the PFC 331 and 332 pads: I have noticed that the PFC website does not show the 332 as an option for the e46 M3 rear even though Bimmerworld sells them for that fitment. That’ makes me curious, I suppose these products are newer

This is a fun topic. I hope to learn more about the pad and options that work well for HPDE on stock calipers. My approach will be to stick with one manufacturer that focuses on our application/use and learn to use their products. I went with PFC because they are reputable, have a couple options for track, and made in the USA

[bigjae46]

Yes, the pads are properly bed in on the rotor. But that is an important step, so I appreciate you mentioning this.

I think I just don’t have enough heat in them. I supposed I should just go faster :-)

My son used these PFC08s and loved them on this same track in May. He has demonstrated (in other sports and this one) a much higher tolerance for late braking and confidence in turns than I have.

Not trying to treat you like a retard....but I have to ask. How did you bed the pads in? It has been a pad bedding issue every time I've encountered this complaint. Typically, I smell brakes and sometimes a little smoking after bedding the pads.

The odd thing is PFCs are generally easy to bed in. The only pad I've had issues with were Pagids.

I'm not up to date on the PF compounds but the PF11 are supposed to be like the old PF01s. The PF01s have a higher initial bite, are easier to control than an PF08, and would last a long time as long as you didn't cook them. The PF08s are more tolerant of overheating and can withstand higher temps.

The only other thing I can think of is the tires are old. The PS4S get rock hard when overheated a couple of times. Once rock hard, they will last another 100k miles with zero wear but the grip will be total crap. Usually you will notice because it will be drift city and it feels like the brakes are crap...unless you have DSC on and then it will just feel like crappy brakes.

[eacmen]

On the outlap as long as I don't have traffic behind me I will threshold (but avoid ABS!) brake more than needed at each corner. This helps warm the pads up for the first hotlap, but I don't find the pads truly up to temp until the second or third hotlap. I have brake ducts but will often cover them up on cooler days to help get heat into the brakes.

[OldRanger]

Did you bed the pads in? What you describe sounds like the pads not being bed in.

Track pads which are high temp pads work differently than lower temp or street pads. Street pads rely on pressure and friction. A track pad relies on heat, pressure and some adhesion. High temp compounds actually stick to the rotor so it is absolutely critical to bed in the pads.
.

Yes, the pads are properly bed in on the rotor. But that is an important step, so I appreciate you mentioning this.

I think I just don’t have enough heat in them. I supposed I should just go faster :-)

My son used these PFC08s and loved them on this same track in May. He has demonstrated (in other sports and this one) a much higher tolerance for late braking and confidence in turns than I have.

[bigjae46]

Did you bed the pads in? What you describe sounds like the pads not being bed in.

Track pads which are high temp pads work differently than lower temp or street pads. Street pads rely on pressure and friction. A track pad relies on heat, pressure and some adhesion. High temp compounds actually stick to the rotor so it is absolutely critical to bed in the pads.

The goal of bedding the pads in is to get the pads hot enough to transfer a layer of pad material onto the rotor to promote high temp adhesion with the pad.

You lose bite and stippling power when the pads are not bed in and significantly increase wear on the pads and rotors.

[Estoril]

Thanks for the questions, I understand.

Regarding dips in the track and possible rebound/grip issue: I have Ohlins R&T w 400/700 springs with dampers set to 6 and 4 from hard front/rear respectively. The ABS gets involved, but not dramatically. I had DSC on the whole time, my car is a 2005/MK60 - it was interveneing predictably and still allowing good speed. I believe there is fairly good traction for PS4S, but I'm keeping my eye on those damper settings. I made a change before this HPDE - increased/firmed up the dampers 10% (2 cllicks) from my last track day after adding a GC Front Sway set soft and the 700# rear springs. My concern, like yours would be that the rebound damping is too firm. Related: the chassis behaved well on the ski jump at speeds around 100mph.

I use stock calipers that I rebuilt after my son drove/HPDE in May. Slider pins are clean/straight, I'm using anti-rattle clips, the pad wear is even and the rotor sweep looks right. I have a solid brake pedal with no signs of air in the lines (no fading, no need to pump the brakes). I use a pressure bleeder, but I would be too bold to say things are 100%. Since the pedal doesn't fade nor require any pumping, I don't think I have an issue with air or knockback.

More on knockback: it is possible, but minor. I occasionally get a minor pull to the left (from the front) that I noticed more on my other track day in August. If there is/was any, it would be reasonable based on the conditions of the front wheel bearings that I just changed this week. I presume originals with 166K miles. The right one came off with finger-only pressure turning the 3-jaw puller and was rather noisy. They were in need of replacement for track duty.

Absent additional observations (you've been detailed), I would look at suspension set-up given the single point on the track where you are having the issue and my earlier note on the depression at the beginning of the braking zone in that specific turn. If it were pad/caliper related, you would have had the same/similar problem braking into the Karussel, and turns 11 and 17.

Offer: I am on Shenandoah again with NJ BMWCCA (a great group) October 14-15. They run an extended course that no-one else runs with 3 additional turns at Old Ram. I would be happy to either instruct and work on the issue with you, or do a few laps with you to understand it better. (Note: I think the registration discount ends tonight: https://www.motorsportreg.com/events...-jersey-360258 . You're welcome to go out with me and get a feel for my braking as well). I know the course well and have a sense of the topography that could affect your brake feel, as well as variations to the line to avoid those features.

[elbert]

I'm relatively new to HPDE; driving at an intermediate level. My car has Michelin PS4S, track-capable suspension and alignment, and I use PFC08 with Motul 600/660.

Reeling in the speed from 110+ to 40 mph is high adventure - there is a bit of a vague feeling for the first second or two. Even after 5 or more laps, if the situation involves a braking zone after a long straight there is a period of time...maybe 1 or 1.5 seconds where these pads are heating up and the friction is increasing. In the process, at least initially they don't really seem to bite like I would expect. ]

tl;dr version
Your pads need more heat

long version
I had the same experience as you with my 08 pads. I fixed it by gaining speed.
I took a 10 year break from track events (work, family), and started back up in 2018. When I started up again, I was very rusty, maybe intermediate level at best.
For the first few events, I would experience the split second lag before having any bite. I was unfamiliar with the pads at the time, so I thought that was how they worked.
However, now that I'm getting back up to speed (heh), I don't have the lag anymore.

As a side note: you really need to turn off your DSC.
- It is detrimental to your development as a driver
- It can overheat your rear pads
- It will literally slow you down