Some issues from a 2-day HPDE...

ChrisSlicks · 05-05-2011, 05:49 PM

Quote:

Originally Posted by flashburn

Is it possible that my rotors are warped and it isn't from deposits? I looked them over and didn't see anything, but if it's subtle, I doubt I would of.

edit: I meant that I looked them over for any warp-age.

You can't tell the warpage by eye, you need to measure the runout with a dial gauge to see what the variation is as the rotor turns. Runout of a few thousands of an inch will cause vibration.

I had the same problem as Mike with the Ferodo 2500's overheating and leaving deposits on the rotors, my front pads were destroyed in about 3-4 sessions. I used a different pad to try and clean it up which worked a partially but not completely.

flashburn · 05-05-2011, 05:55 PM

Hmm okay. I'll just have the wheel shop take a look at them then in a week or so. Luckily with the stock pads the vibration isn't too bad, I didn't even notice it at first.

cossie1600 · 05-05-2011, 06:01 PM

if i recall correctly, new rotors are 40 or 50 bucks, i would buy new ones and call it a day

flashburn · 05-05-2011, 06:11 PM

Are they really?

So much for using the need to get new rotors to help justify getting a BBK. I'll look into that and just buy some new rotors for the fronts then.

ChrisSlicks · 05-05-2011, 06:53 PM

Quote:

Originally Posted by cossie1600

if i recall correctly, new rotors are 40 or 50 bucks, i would buy new ones and call it a day

Maybe crappy autozone ones (if they exist) but anything decent is around 260 per axle.

Sharif@Forged · 05-05-2011, 09:50 PM

The most important thing, is that you have the correct brake pad (heat range) for your intended driving and vehicle/setup. The only way to accurately determine this is with a pyrometer and/or temp paint. I can make a recommendation this is going to be close, but it won't be perfect without feedback from the driver and some carefull data collection. Since we track many of the same lines of cars over and over again, we've got a pretty good baseline as to what works and what doesn't.

To the OP, the vibration you are feeling could be warpage or deposits as others have alluded to. Keep in mind, your brakes and rotors will be happiest if you use them HARD for the shortest period of time. If you feather the brakes at any point on the track or brake softly and then increase pressure as the braking zone ends then you will likely continue to have some vibration as you will not be applying enough pressure to uniformly transfer material to your rotors.

cossie1600 · 05-06-2011, 01:18 AM

Quote:

Originally Posted by ChrisSlicks

Maybe crappy autozone ones (if they exist) but anything decent is around 260 per axle.

Rotor is a chunk of metal. Get it from a reputable brand and you will be okay, it's just a giant heat sink. If anything, cryotreating it is very important on a track car. I had a set treated on my Corvette and it made a huge difference in crack resistance on the cross drilled rotors

ChrisSlicks · 05-06-2011, 08:21 AM

Quote:

Originally Posted by cossie1600

Rotor is a chunk of metal. Get it from a reputable brand and you will be okay, it's just a giant heat sink. If anything, cryotreating it is very important on a track car. I had a set treated on my Corvette and it made a huge difference in crack resistance on the cross drilled rotors

Metalurgy plays a roll as well. If you're buying cheapos who knows what they threw into the mix. Just as important as cryotreating in these large rotors is stress relieving after the casting, i.e. keeping the rotor at a high temperature after the cast and then a gradual cool down.

I checked the autozone website, they want $200 for the front axle and list the rotor weight at 14lbs (typo I'm sure).

cossie1600 · 05-06-2011, 09:00 AM

frozenrotor has one cryo treated for 131. there are other sites that had it cheaper, i have to check again.

flashburn · 05-06-2011, 09:35 AM

Quote:

Originally Posted by Sharif@Forged

To the OP, the vibration you are feeling could be warpage or deposits as others have alluded to. Keep in mind, your brakes and rotors will be happiest if you use them HARD for the shortest period of time. If you feather the brakes at any point on the track or brake softly and then increase pressure as the braking zone ends then you will likely continue to have some vibration as you will not be applying enough pressure to uniformly transfer material to your rotors.

Thanks. I think I am guilty of doing that, at least a bit. I tended to get on the brakes more after the initial application for at least parts of the first day.

Do you have a recommendation for a set of cheap-ish rotors that can handle doing track days with Carbotech XP10/8 pads?

cossie1600 · 05-06-2011, 10:49 AM

according to advance auto, they have rotors for it at 47 bux and 100 for wagner. they have 20 to 30% off all the time

ChrisSlicks · 05-06-2011, 11:42 AM

Quote:

Originally Posted by cossie1600

according to advance auto, they have rotors for it at 47 bux and 100 for wagner. they have 20 to 30% off all the time

That is for base brakes (12.5" diameter). Cheapest they have for the front for the sport brakes is Wagner $138 each.

05-05-2011, 05:55 PM	#32 (permalink)
flashburn A True Z Fanatic Join Date: May 2009 Location: Central Florida Posts: 1,884 Drives: '12 Corvette GS 6M Rep Power: 19	Hmm okay. I'll just have the wheel shop take a look at them then in a week or so. Luckily with the stock pads the vibration isn't too bad, I didn't even notice it at first. __________________ Current Ride: 2012 Chevrolet Corvette Grand Sport Centennial Edition Carbon Flash 6M Previous Ride: 2009 Nissan 370Z Sport Platinum Graphite 7AT

05-05-2011, 06:11 PM	#34 (permalink)
flashburn A True Z Fanatic Join Date: May 2009 Location: Central Florida Posts: 1,884 Drives: '12 Corvette GS 6M Rep Power: 19	Are they really? So much for using the need to get new rotors to help justify getting a BBK. I'll look into that and just buy some new rotors for the fronts then. __________________ Current Ride: 2012 Chevrolet Corvette Grand Sport Centennial Edition Carbon Flash 6M Previous Ride: 2009 Nissan 370Z Sport Platinum Graphite 7AT

05-05-2011, 09:50 PM	#36 (permalink)
Sharif@Forged The370Z.com Sponsor Join Date: Dec 2008 Location: Marietta, GA Posts: 840 Drives: 2009 GT-R, 2010 370Z Rep Power: 17	The most important thing, is that you have the correct brake pad (heat range) for your intended driving and vehicle/setup. The only way to accurately determine this is with a pyrometer and/or temp paint. I can make a recommendation this is going to be close, but it won't be perfect without feedback from the driver and some carefull data collection. Since we track many of the same lines of cars over and over again, we've got a pretty good baseline as to what works and what doesn't. To the OP, the vibration you are feeling could be warpage or deposits as others have alluded to. Keep in mind, your brakes and rotors will be happiest if you use them HARD for the shortest period of time. If you feather the brakes at any point on the track or brake softly and then increase pressure as the braking zone ends then you will likely continue to have some vibration as you will not be applying enough pressure to uniformly transfer material to your rotors. __________________ Sharif@Forgedperformance.com General Manager/Certified Tuner/NASA-PCA-BMWCAA Instructor JRZ RS1's Available NOW...PM me Cobb ProTuner, Uprev ECU Flash, FCON Vpro, Haltech, Motec Certified Last edited by Sharif@Forged; 05-05-2011 at 09:52 PM.

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05-05-2011, 06:01 PM	#33 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	if i recall correctly, new rotors are 40 or 50 bucks, i would buy new ones and call it a day

05-06-2011, 09:00 AM	#39 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	frozenrotor has one cryo treated for 131. there are other sites that had it cheaper, i have to check again.

05-06-2011, 10:49 AM	#41 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	according to advance auto, they have rotors for it at 47 bux and 100 for wagner. they have 20 to 30% off all the time