992gnt

iTrader: (5)

Does anyone monitor rotor temps after a track session? I had some REAL bad vibration problems this past weekend after the brakes were good and hot - bad enough to kick the ABS on and keep me from being even remotely fast. After a cool down lap and checking tire pressures first, I was seeing rotor temps well over 600 degrees. Was high heat warping the rotors on track? Once cooled off, I have no vibrations at all. I'm trying to determine what I need to do to fix the problem without spending money on the wrong things. I'm running stock rotors, no air guides, and Ferodo DS3000's (just at the track). If better rotors will fix the problem I'll get some RB one piece rotors. If better cooling alone will fix it, I'll address that and leave the rotors alone.

I'm looking for some input here, and buying new rotors, pads, cooling ducting, etc. all at once is not in the budget. I've never had this type of problem before so I'm not sure where to start. I guess the good news is that I'm getting faster and finding the limits of the stock bits. The car will do at least 3 more track events this year, maybe as many as 5.

kingkyle

iTrader: (25)

My stock rotors with track pads got to 450 to 500 deg right off the track.... My new Performance Friction rotors with race pads get to 550 right off the track. My calipers are now maroon/brown.

I think you problem might be warped rotors. when you come off the track roll your car a foot or two to move the caliper heat to a new part of the rotor. This helps the rotor cool more evenly. the caliper retains the most heat.

djh

That's a pretty aggressive pad. But I ran into the same thing on the stock rotors with DS2500s. I replaced them with Stoptechs and have had no vibration at all running DS2500s or Hawk Blues.

Dave

992gnt

iTrader: (5)

Yeah, my calipers have been brown for a while now. I'm thinking that the rotors are just warped and heating them up makes things worse. I guess the question now is whether or not to spring for a two-piece rotor over a one-piece and what pad to run with them.

RazorLab

iTrader: (8)

Where the pads a new set you had just put on?

Did you bed them in correctly?

Are you doing a proper cool down lap?

You said you only use the DS3000's at the track, so you are mixing pads on the same rotor. Bedding them in properly is a MUST in this situation. You need to get the street pad compound off the rotor and transfer the race pad compound to the rotor.

I swap pads at the track and I can tell if I don't bed them in well, they will vibrate much like what you are seeing.

992gnt

iTrader: (5)

They are not new pads, and I used them most recently at Mid Ohio a month ago with no problems. I usually swap pads a few days ahead of the event, so I can bed them in before hand. How are you bedding them in; anything different than a normal bedding in procedure? Cool down laps are good (AFAIK), low revs little to no brake use.

What rotors/pads are you using on the track?

RazorLab

iTrader: (8)

interesting. How are your rotors looking? Getting close to minimum spec?

Did they start vibrating early in the day or later?

I use PMU MAX900 with PF 2-piece rotors

machron1

iTrader: (1)

My rotors often turn blue from heat on the track. When I initially put Hawk Blues on, about the 3rd - 5th lap I had a bad vibration that went away after a few more laps. I believe it was pad transfer, as warped rotors do not true themselves with usage. You might be experiencing the same.

992gnt

iTrader: (5)

I've had pad transfer at the track before and it does go away, this vibration started in the 3rd session of the day and never got better - only worse the harder I used them. On the drive home and subsequent trips they have had no vibration though. My original stock rotors were down to the service limit so I got these stock rotors that were take offs from a theft recovery with plenty of meat on them. I was going to mic the rotors when I swap the pads back, but I wouldn't expect them to be anywhere near minimum spec.

RazorLab

iTrader: (8)

I would get them checked out.

They might have internal cracks that open with heat.

heeltoer

the stock rotors are downright crap. I know since ive experienced this vibration issue now with two sets of rotors (at 500 for the fronts its not cheap). Even with proper bedin it still happens everytime when using my raybestoes ST-43 pads. This pad is fairly abrasive so that was part of the issue but i found buying cheap centric rotors a much better deal. These have lasted me 3 days now without any vibration and even after changing to my stock pads and back. Plus they are super cheap.
http://cgi.ebay.com/ebaymotors/ws/eB..._BIN_Stores_IT

this is where i bought mine last time, dimpling or slotting your rotors could increase rotors/pad longevity as well.

the ideal solution is to get a brake ducting system that directly shoots air into the rotors from the hub. There are some custom and premade versions (search) of this but it will increase brake longevity and rotor life.

peter*g

iTrader: (55)

Check this out for a little more information on brake judder:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

5-600 degrees is not that hot for brake temps. I have seen over 1000 degrees racing. Hell, if when you come in from a hot lap smoke isn't pouring out from the wheel, they're not that hot. ;-)

WarmPepsi

iTrader: (35)

haha, my CALIPERS are 5-600 degrees normally.

You only smoke the first session, as you burn off all that brake lube you put behind the pad.

I really need to get me a pyro gun and do some testing though.

peter*g

iTrader: (55)

Who uses brake lube? ;-)

And as for smoking, I meant like the attached (pit stop photo).

WarmPepsi

iTrader: (35)

haha, i know, x4.

I do, so i don't get the squeeks before i'm on track

Kinda back on topic, i know forge makes the ducts, but is there anything else out there worth a darn for cooling ducts? ( i've long since had the mitsu ones, and they're a joke )