[kweevuss]

I have a 2SS with the normal 4 piston setup. I am at 15k miles, and have just completed by 3rd HPDE day over the course of a year.



The first two events the brakes were flawless, but yesterday about half way through my first session (in total there are 3x20 min sessions) the brakes started pulsating. They still felt strong the rest of the day, but of course that was somewhat annoying. My first thought was I would have to replace them, but interesting enough on the street I have no issues under normal braking. It seems to only appear if I am applying quite a bit of force on the pedal.



I have read quite a few posts on the forums where people say the rotors should last a long time, and many have had them resurfaced. I know on normal passenger cars, resurfacing is not really a thing anymore with how cheap rotors are but it seems like these are still in decent shape from physical apperance. I'm assuming there is just some pad material that is on them. Or is it possible there is anything else I can look at?



My question is, for non 6 piston brakes, is a resurface worth it at all? I will be going to one more HPDE event in August, and I wanted to make sure I had the issue sorted by then. If I had to buy new rotors, that is ok it just seems like the factory ones are not up to heavy track days.

[kropscamaro16]

what pads are you on and stock fluid or?

[kweevuss]

Originally Posted by kropscamaro16

what pads are you on and stock fluid or?

I am still on OEM pads. I have exchanged the brake fluid with motul 600 and bleed them before my 2nd track day about a month ago. The one yesterday I did not, but the instructor did mention it is best to do it each time so I will add that to the list, if that makes any difference.

[Wontspeak]

It could be that you picked up some tire turds ��. *laughs* I picked a bunch up a few times, felt like the car was going to fall apart.

[kropscamaro16]

i used to be on oem pads and ss lines and fluid and then switched to powerstop track day pads and they had alot more bite priced out new st43 pads and rotors and realized it was just better to find a bbk kit after talking to multiple people about tracking on the oem 4 piston brembos

[kweevuss]

Originally Posted by kropscamaro16

i used to be on oem pads and ss lines and fluid and then switched to powerstop track day pads and they had alot more bite priced out new st43 pads and rotors and realized it was just better to find a bbk kit after talking to multiple people about tracking on the oem 4 piston brembos

Ok that’s interesting. With the big brake kit, are you referring to the 6 position setup?

[cdrptrks]

Maybe you were braking hard enough to engage ABS and that was the pulsating? You would feel it in the brake pedal if so. Maybe try finding an empty road and panic stop from 50+ mph with the brake pedal pressed as hard as possible to see if does the same thing.

[kweevuss]

Originally Posted by cdrptrks

Maybe you were braking hard enough to engage ABS and that was the pulsating? You would feel it in the brake pedal if so. Maybe try finding an empty road and panic stop from 50+ mph with the brake pedal pressed as hard as possible to see if does the same thing.

Thanks this was a good suggestion. Now driving it again, I am getting the same feeling anywhere from medium to heavy braking. I do not believe I was going that hard to engage abs on track for sure. I probably should have drove it again before I made the post.

I guess that leads me to another question as I am only beginning to learn about all the brake options. Is using a track focused pad and stock rotors good options? I would also switch back to oem pads for street driving. From my understanding the higher temp range of the track pads, they would be a lot less likely to transfer material to the rotor. I don’t intend to be in competitive races or anything and would use this for a few HPDE events and auto cross per year.

[cdrptrks]

Hmm double check your lug nuts are torqued to 140 ft-lbs and that you haven't thrown (lost) any wheel weights if you had them previously. Also look for any pieces of rubber from the track that stuck to the hot wheel or tire that could throw off your wheel balance like someone else mentioned.

Also maybe visually inspect the rotors for uneven pad deposits and if you can see/feel any then use garnet paper to sand them flat. This has happened to me and others when parking the SS 1LE with 6 piston brakes for a few days while the brakes are still wet from a car wash but in my case it was so bad that the car was undriveable and not sure if it would apply to your situation of starting during a session and 4 piston calipers.

[kropscamaro16]

yessir i actually went with the zzp big brake kit and i always make sure to torque my luggnuts before every session

[kweevuss]

Thanks everyone for the suggestions. I did clean the wheels very well yesterday, and I did noticed a lot of rubber inside the wheels so that shouldn’t be an issue now. I did torque the wheels each session as well and found them to be inspec. I will look at the wheel weights though, that’s a good point.

I also could imagine there being deposits on the rotor, I will try the sand paper method as well.

[kropscamaro16]

i used to switch from the z26 pads then back to my track pads and i always sandpapered the rotors first then i just left the track pads on and said f+ck it haha but seriously the zzp bbk was the best thing i did now i need more/better tires!

[TWG1]

Pulsating is usually warped rotors. I don’t have your setup, but it sounds likely. You can verify if that’s the cause if the pulsating frequency decreases as you decelerate. They are more likely to warp when worn (less metal to dissipate heat, less rigidity). Sometimes they’ll warp if you drive through water when really hot. Also seems that some cars are more prone than others.

I always change them out once they start pulsating. I figure the vibes can’t be good for the car, and would likely wear out other components prematurely (bushings, seals, etc). Turning rotors is a lost art, and they usually just warp again due to further removal of material. Maybe someone will chime in with a good way to determine which ones are warped.

[LJenkins1LE]

Originally Posted by TWG1

Pulsating is usually warped rotors. I don’t have your setup, but it sounds likely. You can verify if that’s the cause if the pulsating frequency decreases as you decelerate. They are more likely to warp when worn (less metal to dissipate heat, less rigidity). Sometimes they’ll warp if you drive through water when really hot. Also seems that some cars are more prone than others.

I always change them out once they start pulsating. I figure the vibes can’t be good for the car, and would likely wear out other components prematurely (bushings, seals, etc). Turning rotors is a lost art, and they usually just warp again due to further removal of material. Maybe someone will chime in with a good way to determine which ones are warped.

Brake rotors do not warp. Rayebestos, Centric, and others have white papers explaining why.

Sounds like the OP has exceeded the temperature rating for the pads, and they left uneven pad deposits on the rotors. He is describing exactly what happened to me with my 1LE on stock pads on track. I switched to a track pad and performed a bunch of cold stops to clean them up. Worked like a charm. Or use garnet paper like cdrptrks suggested. I do this when going back to my street set up.