First HDPE Event, Massive Brake Squeal and Noise

[mimarcos]

I just completed my first HDPE event (HoD, Pocono Raceway, 9/22), and holy hell it was amazing. I thought I understood my M, but I learned that, well, I have a lot more to learn.

One of the things I'm looking at now is brakes. Throughout the day, I didn't experience much, or really any, fade, but I did have a pretty big problem with squealing and rattling brakes. The problem really only started after my first "pucker up" brake coming off the back straight. For the next few sessions, the brakes were singing a pretty miserable song between about 20% and 50% application. On the last session, after I took a ride along with my coach and saw how he was driving, I pressed a little harder, and the intense squeal turned into what seemed like mechanical chatter. It sounded almost like something was loose. The pedal feel never changed, and I didn't experience fade.

I'm sure at some point I'm going to want to upgrade to better brakes. But right now, I want to see if there is a simpler solution to this problem. I know my brakes haven't been changed since the original owner. The car has just over 5k miles on it, as an '06, and I bought it with 2k in the summer. Is it possible that getting new pads could resolve this problem for my next track day? If so, does anyone have any recommendations for decent street/track pads that would fit on a stock setup?

PS - video of the run will be up, when it finishes uploading, at

if anyone wants to comment/critique my fourth session of the day.

Thanks!

[i2ichal2dZ4M]

If you're on stock pads, not supose to squeal. might want to check out the system.

[mimarcos]

Hmm, thanks. From what I described, do you know what part of the brakes that might indicate a problem with?

[i2ichal2dZ4M]

Originally Posted by mimarcos

Hmm, thanks. From what I described, do you know what part of the brakes that might indicate a problem with?

check all four corners to make sure all calipers has their anti-rattle clip still installed.

http://www.bimmerfest.com/forums/att...1&d=1277480673

[mimarcos]

Just took a quick peek, they're all there. Can't vouch for how well they're installed, but at a minimum I can see them.

I doubt quick snaps will provide an accurate analysis of the problem, but I've attached photos of my rear pad/rotor, front pad/rotor, and some of the holes in the rotor on the front - they looks like they have deposits in them. And the pads look... torn. I don't know if that's normal or not.

[Geauxkart]

Get new pads and have the rotors turned. Looks like you got them too hot, and you melted them a bit.

[Kgolf31]

Originally Posted by Geauxkart

Get new pads and have the rotors turned. Looks like you got them too hot, and you melted them a bit.

IRRC you cannot turn these rotors.

OP - You didn't brake hard/fast enough. Most likely you were hanging on the brakes, thus overheating and streaking the rotor. I haven't watched the video, but the streaking on the rotors makes me think this.

Get some higher aggressive pads and do a re-bedding of the rotor, the streaking should come off.


To make sure this is accurate, do your brakes pulsate on the road now?

[mimarcos]

Kgolf, very slight pulsation. Leaving the track, the squeal and pulsing slowly went away. By the end of my trip home, most of the pulsing was gone. I haven't driven it since Sunday, but I plan to take it out around lunchtime today, I'll let you know if it's noticeable.

When you say rebed, are you talking about resurfacing? I've seen that term used before.

Any recommendations for pads that will work well on the track, but won't squeal or be finicky on the road?

[Kgolf31]

Originally Posted by mimarcos

Kgolf, very slight pulsation. Leaving the track, the squeal and pulsing slowly went away. By the end of my trip home, most of the pulsing was gone. I haven't driven it since Sunday, but I plan to take it out around lunchtime today, I'll let you know if it's noticeable.

When you say rebed, are you talking about resurfacing? I've seen that term used before.

Any recommendations for pads that will work well on the track, but won't squeal or be finicky on the road?

Resurfacing, in my head, is physically turning or machining the rotor down when off the car.

Rebedding is the process you need to do when you get new brake pads. It involves several 60-5 MPH stops (around 5-6) to get new material on the rotor and level the pad to avoid uneven wear. With a new brake pad material, they should be able to scrub off that extra material that is now on the rotor

To answer your question, there is no pad that will give you good performance with maintaining the quiet you want on the street. Any OEM or like pad will perform well on the street, but will fade and fail quickly under any extra stopping, like on the track.

My first 2 HPDEs I've ran HP+ Pads. I will no longer run these pads because towards the end of my sessions, even with braking early, my pads were starting to fade and ABS was kicking in very early...They are awesome on the street, and good at autocross because of their initial bite. But they scream like a bus.


Ultimately if you do continue to track, I'd look for dedicated pads.

[mimarcos]

Thanks for the info. I just took her for a quick spin and there is no pulsing in the brakes. They work just like they before the event.

I was looking for replacement brakes, and I thought that the StopTech Street Performance Brake Pads looked pretty good for an all around replacement that'd work well on the street and maybe better on the track.

Out of curiosity, can I have two sets of pads on the same rotor? More aggressive pads for track days and one for cruising around town? Once you'd re-bedded the pad and rotor, do you have to repeat the same procedure every time they're swapped?

I've never done any mechanical work on cars, so I have no idea what goes into the whole process. I'd like to be able to change the pads myself, but I'm going to need to do a little bit more research to find out what's required. I'd imagine a jack, jack stands, and some basic tools.

[StickMon]

http://m3.madrussian.net/diy.shtml

[JasonH]

What are you recording your video and data with?

[mimarcos]

I used a GoPro for the video, a cheap little Bluetooth ELM327 data sensor (http://www.bimmian.com/Wireless-OBD-...for-BMW-E85-Z4) to capture data, which I was sending to my phone (Samsung GNex), running Torque (https://play.google.com/store/apps/d...l.torque&hl=en). At the end of the day, I used RaceRender 2 (http://racerender.com/Products/index.html) to overlay the data.

It took me a while to configure the gauges to be exactly how I liked them, I spent about a week playing with RaceRender and sample runs around town to really get it down.

[JasonH]

Neat. Thanks for the reply. I usually use Harry's Lap Timer, but I haven't had consistent luck with it and Bluetooth OBDII. I have the other hardware and software you do (my actual phone is a Nexus 4, I use an old iPhone 4 just for HLT) so I could potentially do the same thing. I've used RR2 to combine GoPro video and HLT data, but it's typically just easier to let HLT do the overlay.

[Kgolf31]

Originally Posted by mimarcos

I used a GoPro for the video, a cheap little Bluetooth ELM327 data sensor (http://www.bimmian.com/Wireless-OBD-...for-BMW-E85-Z4) to capture data, which I was sending to my phone (Samsung GNex), running Torque (https://play.google.com/store/apps/d...l.torque&hl=en). At the end of the day, I used RaceRender 2 (http://racerender.com/Products/index.html) to overlay the data.

It took me a while to configure the gauges to be exactly how I liked them, I spent about a week playing with RaceRender and sample runs around town to really get it down.

Interesting. You should do a DIY for others about how to exactly overlay using the OBDII and Torque. I'm assuming you're using a GoPro for video?


I use a free copy of Race Render for just video comparison. Did you buy the deluxe or ultimate version or something?

[mimarcos]

Originally Posted by JasonH

Neat. Thanks for the reply. I usually use Harry's Lap Timer, but I haven't had consistent luck with it and Bluetooth OBDII. I have the other hardware and software you do (my actual phone is a Nexus 4, I use an old iPhone 4 just for HLT) so I could potentially do the same thing. I've used RR2 to combine GoPro video and HLT data, but it's typically just easier to let HLT do the overlay.

You know, I tried to use HLT, but I was really worried about it - I couldn't seem to get reliable data when testing it out. Torque was pretty easy to use and showed data nicely. It also exported to CSV, which made things very easy for me. I'm a software engineer so I used some of the metrics to calculate gear (that's not tracked by the software by default). I did a few test runs with DashCommand as well, and while I really loved it, I switched off to Torque to try and fix a data sample frequency problem. The problem wound up being my fault, but I just stuck with Torque since my event was coming up pretty quickly. DashCommand also exports to some proprietary log format, which you need to more software to convert to CSV.

Interesting. You should do a DIY for others about how to exactly overlay using the OBDII and Torque. I'm assuming you're using a GoPro for video?

I am using a GoPro Hero 3, it worked out very well until I realized I ran out of storage on my fourth session. In between my fourth and fifth, my instructor took me out in his BRZ, and I applied some of what I learned in that run to my final session. It was the best one of the day, by far. I'll do a write up of how I did everything, there wasn't a lot of detail for my setup so I think it'd be good to compile a guide for my exact configuration.

I use a free copy of Race Render for just video comparison. Did you buy the deluxe or ultimate version or something?

I bought the ultimate. Not really sure if I wasted $10, but it seemed to have a good selection of visualizations to use.

[mimarcos]

Also, just to change what I wrote before, it seems that there is a pulsation in the brakes. Not severe enough to worry me, but enough to notice it, notably at higher-than-city speeds.