Symptoms of pad fade

[dparm]

As I had previously posted, I took the plunge and had a StopTech ST40 BBK installed. I opted for the slotted rotors and am using the StopTech SP pads. The rear brakes are brand new OEM rotors and the same StopTech SP pads. Fluid is Castrol SRF flowing through the stainless front lines that the kit came with. The rest of the car is stock and I track on Michelin PSS.

Now that I have a lot more braking capacity, what are some symptoms of brake pad fade that I need to be on the lookout for at the track?

[M3 Esq]

Long pedal, feels like the brakes are not working. You have a very competent setup there. If you weren't worried about brake fade with the stock setup you shouldn't be worried now.

[roastbeef]

It's when you can't stop as good.

Seriously though, I don't think you'll have a fading problem with street tires.

[E46M3forRay]

Feels like your rotors is soaked in oil. No bite

I don't think you'll ever experience brake fade on those stoptechs. Awesome brakes btw

[dparm]

Maybe I didn't phrase my original question well, so I apologize. What I'm trying to understand is the difference between pad fade and fluid fade (boiling).

Is pad fade going to be a firm pedal but greatly reduced stopping power, whereas fluid fade/boiling is where the pedal just goes to the floor/has much more travel?


In the interest of full disclosure, I have some track days scheduled at courses with some very long straight sections. At a previous event at one of those courses, I was doing 110-120 at the end of the straight section and had to bring the car down to about 40mph.

[M3 Esq]

Fade can be caused by either exceeding the thermal capacity of the pads and rotors or by boiling your fluid. If you overheat the pads you might experience a firm pedal but the car won't stop. If you book the fluid you'll have a mushy or long pedal. At least that's how I understand it. I've never boiled my fluid.

You're running a BBK with SRF. SRF has an extremely high boiling point. I doubt you're going to either boil the fluid or overheat the brakes with that setup in a DE.

[dogbone]

Originally Posted by dparm

Maybe I didn't phrase my original question well, so I apologize. What I'm trying to understand is the difference between pad fade and fluid fade (boiling).

Is pad fade going to be a firm pedal but greatly reduced stopping power, whereas fluid fade/boiling is where the pedal just goes to the floor/has much more travel?


In the interest of full disclosure, I have some track days scheduled at courses with some very long straight sections. At a previous event at one of those courses, I was doing 110-120 at the end of the straight section and had to bring the car down to about 40mph.

Personally, I would not do a track day with 120-to-40 slow downs with a street/track pad.

You have a BBK, you have good fluid------why cheap out on the pads? Get a medium torque dedicated track pad, and you will have a MUCH better experience.

I cannot see any reasonable justification for buying a BBK, putting in SRF and then handicapping the whole system with a shit pad.

[Richbot]

I know from personal experience with my STR40 front kit that stoptech street performance pads will fade pretty severely on track if used near their potential for more than a couple laps they fade and don't come back. I was quite disappointed after some reviews on here but frankly should have known better. Track pads for track street pads for street. Pad swap with these calipers takes about as long as pulling the wheel

Also if you have fluid flowing through your brake lines you have bigger problems than pad fade...lol

[admranger]

One of the benefits of BBKs (supposedly) is that pad changes are quick and easy. I'd run track pads and you'll likely not have fade (especially on street tires).

BTW: what tire pressures are you running on your PSS'? I've never tracked them but I might in a couple of weeks...

[dparm]

I'm going to try the StopTech pads as they were included with the BBK. If I don't like them on the first track day, I'll just buy a set of track pads.

I run the PSS at OEM pressures. They seem to do fine there.

[Richbot]

If you aren't tearing up PSS on track I think you will be one of the people who finds the street performance pads perfectly adequate

[dogbone]

Originally Posted by dparm

I'm going to try the StopTech pads as they were included with the BBK. If I don't like them on the first track day, I'll just buy a set of track pads.

I run the PSS at OEM pressures. They seem to do fine there.

Based on your comments about tires, it is possible you're not driving hard enough to overwhelm the brake system. I don't mean this as an insult. I'm simply saying that if you're running PSS tires at OEM pressures, and you say it's fine, then I have to conclude that you're not pushing the tires hard enough to raise the PSI's very much. If a person in SoCal went to a SoCal track with OEM pressures in his PSS tires and drove hard, the tires would come back at over 50 PSI, and you DEFINITELY do not want that. So, if that's the case, then maybe the street/track pads will hold up for awhile. But I still don't see why you would go through all the expense of a BBK and SRF and then just use the hybrid pads included in the box, especially when you have been given specific advice not to do so. I suggest that you learn how to change pads and carry dedicated track pads with you.

The topic of brakes for me is never an academic or theoretical exercise. Nothing on the track is more important than brakes. I always refer back to my mechanic's comment: "It's brakes man. Don't mess around with them."

[M3 Number 86]

I tried pfc08 last event out and wow they stayed consistent throughout the whole day compared to my xp12.

I was too lazy to swap them back to oe pads and have driven a few days city on them and I feel like I can just leave them on.

Try these pads on your stop tech. They are smooth, long lasting, and you can possibly just leave them on for street duty as well. Squeals but not loud at all.

[///Mobbin]

Thought I would drop a comment here on my experience with Castrol SRF. My plan was was to run it for an entire year with no bleeding to see if it could last. It's now been 6 months and over the weekend it held up well but in the warmer afternoon sessions I noticed that late in a session in some of the harder braking zones my pedal would soften a bit requiring additional pedal travel to slow the car in the same distance as it did on prior laps (more than I would prefer). It also caused me to go deeper than I wanted to before turn-in a few times but I suppose that may have just been driver error. Anyway, my conclusion here is that perhaps you still need to bleed with SRF OR it has picked up moisture over time and is just not performing as well as I hoped. I think I may go back to Motul 600 and flushing every ~4 months or so like I used to do. Anyone else tried to see how long they could go with SRF and did you bleed between track days? I was talking with someone at the track and they had a trick quick-bleeder that they engineered, wish I had taken a picture of it now.

For reference, my current setup: Stoptech ST-40 BBK and PFC08's up front.

[dogbone]

Originally Posted by ///Mobbin

Anyone else tried to see how long they could go with SRF and did you bleed between track days?

Going to regular publicly available tracks around California like Buttonwillow, Big Willow, Chuckwalla, Auto Club, Laguna Seca, Sonoma Raceway and Thunderhill, I can leave SRF for the season and it's fine. And I think most agree, I'm pretty aggressive with my brakes.

However, we went to Thermal Club, and that place is the MOST brutal place I've ever seen when it comes to brakes. A single lap has several long straights that go into tight turns, so several times a lap you're bleeding 60-90 mph of speed. If you lap around there for 20 minutes, your brakes get more toasty than any other place I've seen. My friend's AP Racing caliper paint discolored from just 1 day there. They had been fine at all other tracks. My fluid boiled but I didn't realize it until my next track event. At the next event at Buttonwillow, I dove into a turn and the brakes were mushy. I was like, what the hell? A little bleed and all was back to normal.

[dparm]

Originally Posted by dogbone

Based on your comments about tires, it is possible you're not driving hard enough to overwhelm the brake system. I don't mean this as an insult. I'm simply saying that if you're running PSS tires at OEM pressures, and you say it's fine, then I have to conclude that you're not pushing the tires hard enough to raise the PSI's very much. If a person in SoCal went to a SoCal track with OEM pressures in his PSS tires and drove hard, the tires would come back at over 50 PSI, and you DEFINITELY do not want that. So, if that's the case, then maybe the street/track pads will hold up for awhile. But I still don't see why you would go through all the expense of a BBK and SRF and then just use the hybrid pads included in the box, especially when you have been given specific advice not to do so. I suggest that you learn how to change pads and carry dedicated track pads with you.

The topic of brakes for me is never an academic or theoretical exercise. Nothing on the track is more important than brakes. I always refer back to my mechanic's comment: "It's brakes man. Don't mess around with them."

Fair points. I'm still learning about this stuff, so for now, I've just been focusing on technique and not getting too wrapped up changing lots of variables (it's why I just leave the tires at OEM pressures). The only real reason I went with the BBK was because I needed new brakes anyway and I wanted to have plenty of "reserve capacity" for the faster tracks.

What do you suggest I do with regards to the tire pressures? Drop them by 5psi? 7psi? etc.

We all have to start somewhere, so please go easy on me. :-)

[///Mobbin]

Originally Posted by dparm

What do you suggest I do with regards to the tire pressures? Drop them by 5psi? 7psi? etc.

You won't regret that BBK purchase, well worth it!!

I might suggest starting with a 5-6 psi drop from OEM specs (door jamb) and then seeing what your pressures are right when you come off track. They'll probably be up 6-8psi from what you set them at. Also, if you feel like the tires are starting to get greasy mid-session you might take a few more psi out, so maybe 7-8psi under OEM spec when cold.

The "correct" way to do this is with a tire pyrometer but I don't think you need to go there quite yet.

[dogbone]

Originally Posted by dparm

Fair points. I'm still learning about this stuff, so for now, I've just been focusing on technique and not getting too wrapped up changing lots of variables (it's why I just leave the tires at OEM pressures). The only real reason I went with the BBK was because I needed new brakes anyway and I wanted to have plenty of "reserve capacity" for the faster tracks.

What do you suggest I do with regards to the tire pressures? Drop them by 5psi? 7psi? etc.

We all have to start somewhere, so please go easy on me. :-)

The bottom line is we care about your safety! Sorry if we seem a little harsh.

I never tracked a PSS so I can't give you specific numbers. But 5-7 psi down sounds like a reasonable place to start. Remember though, that when you start lower like this, the car can feel mushy initially on the first lap. So, give it a lap of cautious and building speed to warm them up.

PSS doesn't really need a "warm up" lap like race tires as far as grip. They grip right from the start. But, what happens if you leave OEM psi's in there is that, as they heat up, the psi's really increase. And the tires get over-inflated and then don't grip properly in the middle of the session because they're too hard. So the whole thing is a balancing act. You don't care if the car feels mushy on the warm up lap, so go out with them softer, and then as you drive, they'll heat up and increase pressure and psi's will enter a sweet spot that's good for performance in the middle of the session. That's when you want the psi's to be correct.

Anyway, it takes experimentation, and it's affected by how hard you drive, how fast the track is, how warm it is outside. All of us are reducing pressures even further as a day warms up. So there's really no fixed number that you just stick to all the time. These things work in ranges.

[dparm]

Originally Posted by ///Mobbin

You won't regret that BBK purchase, well worth it!!

I might suggest starting with a 5-6 psi drop from OEM specs (door jamb) and then seeing what your pressures are right when you come off track. They'll probably be up 6-8psi from what you set them at. Also, if you feel like the tires are starting to get greasy mid-session you might take a few more psi out, so maybe 7-8psi under OEM spec when cold.

The "correct" way to do this is with a tire pyrometer but I don't think you need to go there quite yet.

What's not clear to me is what the pressures should be when I pull off at the end of the session: as close to the OEM doorjamb values as possible?

[///Mobbin]

Originally Posted by dparm

What's not clear to me is what the pressures should be when I pull off at the end of the session: as close to the OEM doorjamb values as possible?

Really just using those as a reference point, sorry, keep in mind those are cold inflation values for street use (even on the street the psi goes up during use). The end of session value is a bit tire dependent and for PSS will probably be 37-39 psi. What you should be trying to do is maximize the mid-session performance window of the tires. As dogbone said, when you go out, the tires may be a bit soft and feel lazy, then they heat up and are performing their best, then towards the end of a session they can sometimes over-heat and feel greasy or just grip a bit less. You probably don't have a sense for this quite yet but you'll develop it the more you go out and the more you use a specific tire. I haven't actually tracked on PSS so not sure what the window is but its also not a perfect science either, just need to try different things and see what works best for you.

[typicaltrabes]

So I still track PSS as I really wanted to get my skills to a level where upgrading tires wouldn't hide any flaws in my driving.

I have a few events in the next weeks and my current set is running low so will be switching soon but I have about 15 days on them. In my experience (and note: as others have said everyone is very different, it comes down to a whole host of factors) I start my day at about 29-30 PSI. My first session is normally a warm up session for me anyway and I drive about 7-8/10ths. By the end of the first session the PSI will be up at about spec or maybe as high as 38. I take out another 2-4 PSI depending on how the tires feel and that normally is good for the rest of the day.

Always check your PSI as soon as you get off track. It comes down to feel but for me 34-35 all around is the best grip I have found for my driving style. It took me some time with the PSS because as dogbone mentioned they feel sloppy when you first go out on track and they are cold. But as you get in a rhythm you will get a feel for the car and tires. You get to the point where you can feel the difference in a few PSI.

[dparm]

Thanks for the tips. Sounds like the SP pads should be okay since I'm not even maximizing the car's performance on the tires just yet.

My PSS should be toast sometime this summer and I am probably moving to the AD08R in the same size.