Dirty Howie

Appologies for posting this in two forums (here and Tech section)...but not sure if this is a racing issue or general tehnical problem.

I have now cracked my THIRD rotor. Each time it is the LF. I have Baer 2-peice Erradispeeeds with alum hat. First two times were drilled/slotted and I got a SMALL crack from one of the wholes....no brake pulsation. This last crack is a LARGE almost the whole ring surface it is the stronger slotted only rotor and lots of pulsation. I just ordered a new rotor ring again!!!

Yesterday was my third track day on these rotors. I am using Hawk HP Plus pads. I roll my car a few minutes after each session to help prevent this. And usually do a cooldown lap. Did not do one yesterday (forgot) after last session. Did not feel the crack until light freeway braking on the way home. I season the rotors just like the Baer site describes (may not bother anymore however )

So here are my thoughts and would appreciate yours or any advise.

1. Baer doesn't know how to make a LF rotor ring
2. Although all braking is done in a straight line the LF rotor is getting more heat some how. I run in Comp Mode
3. Blocked cooling duct on this side (stock now but will move up later)
4. Maybe there is a left/right brake bias that needs adjustment
5. There is something wrong with the rotor hat that is causing all the rings to crack
6. Everything happens in three's.....just coinsidense.....my luck sucks


DH

C6400hp

Sounds like you need brake ducts????????

UstaB-GS549

Check the right caliper? Does the right side scoring and coloration look about the same?

How about the hole location with respect to the vanes inside. Are all three craked rotors the same?

Walmart bag in the duct on left side?

0Randy@DRM

Cracking rotors is part of roadracing. The only thing that I can come up with is your pistons in the caliper maybe sticky. This could cause something like that. Does it stop straight?

Randy
And yes our brake ducts work.

Olitho

These are my thoughts, too. You should not be cracking rotors within three track days.

While I advocate DRM ducts and spindle holders, again, this sort of cracking should not happen that fast, especially since I know you mostly run WSIR and that track is not very abusive to brakes as some other tracks are.

RAFTRACER

Roadcourses with long straights, heavy braking and right hand turns can cause this issue. Remember if the ABS is active , ( on the right front in this case ) the left front rotor/caliper assy may not be in ABS generating more heat. I just had a customer severly crack a NAPA rotor after a single day @ Putnam, and a weekend a Road America. Alot of heavy braking into righthand corners---especially if the drive likes to trail-brake.

AU N EGL

with Danny.

Right fronts tend to go more with course heavy on right turns.

CHJ In Virginia

I would check the caliper on that side for full functionality. If there is any corrosion, garbage, torn dust cover, etc on one of the pistons, it might not fully retract when you let off the pedal. Constant high pressure causes rapid heating of the rotor on that side. Also check the brake hose. I have seen them become delaminated on the inside rubber core. You can push and get flow towards the piston, but the delamination blocks return flow when you let off the pedal. I have had two of these over the years. It will stump many a mechanic.

emf

Big track is actually really light on rotors . . . most of the heavy braking turns are lefties, too. I'd be leaning more torwards something off w/ the caliper potentially. what's pad wear look like on the right side, howie?

davidfarmer

for what your spending on rotors, I'd spend $50 and put a new caliper on that side just to be safe.

However, I agree that it is just a track issue. Are the pads wearing faster on that side, piston seals melting more, etc. If it is JUST the rotors, then I imagine it is an issue with Baer. Remember, they don't advocate using them at the track. You should consider the Stoptech rotors if you want a race quality rotor

bobmoore2

Agreeing with all the comments above, but especially --
Get brake ducts and spindle boots.

I had a duct hose come loose on one side a couple months ago and I ran one track day with it like that. Later I looked at the rotors on both sides - WHAT A DIFFERENCE! The one with the broken duct hose had several small cracks, and the other rotor was still in great shape. Next time we're at the track together ask me to show you the two rotors. You won't believe the difference.

Bob

GR8-LIFE

weird that it happens on the left. Just to clarify though, You say you aree roadracing with Drilled/slotted rotors??????????????

Dirty Howie

First of all ..... thanks for all the feedback!!!!!

To reiterate and answer some of the questons:
.....It is the LF and only the LF that has cracked. It is Baer Erradispeed 2 peice. Twice with D/S and this last time Slotted only. I talked to Baer today when I ordered a replacement and they said this is the same rotor they use on their big brake package on a car with severe track duty and have had no cracking (but maybe Stoptech is better)

.....I did not notice any differnce in rotor color or pad wear from one side to the other when I prepped car 3 days before race. I also did a complete flush with Super Blue......don't think this would have any effect.

.....I will be checking for duct blockage. My next mod will be the DRM's, but I don't think that explains one side only cracking

.....If its not a blocked duct then these other ideas of the caliper not sliding or a brake line malfunctioning make sense. I'm not sure how to really check these. Getting a new caliper idea makes sense so mabe new SS brake line too??

.....As some of the guys have stated that know WSIR, it shouldn't be hard on brakes. I do all of my braking straight line. I have never heard of anyone else braking rotors only on one wheel from predominantly running WSIR....so although logical the ABS overheating issue should be affecting others, not just me

Thanks again all


DH

bobmoore2

I wonder if it could be the way you have to come out of the turns with your turbo and auto trans. I remember when I rode around the track with you that the power seemed to really kick in suddenly at turn out. Maybe the competition mode is clamping the outside front brake to prevent the rear from spinning out when the power "kicks in" at turn out. Since WSIR is predominately right turns this would heat up the LF more than the RF.

Just an idea, with no expertness behind it...

Bob

Dirty Howie

Bob.....no turbo!!! But I do have have a small 2400 stall on my tranny.


DH

bobmoore2

No turbo? I remember from my ride around that it felt like it suddenly went from about 50 horsepower to about 400 or 500. Was all of that feeling due to the auto trans suddenly shifting down a gear?

FactoryRaceCar

I too think that you have a sticky piston issue. I would change the caliper and see how it goes.

ghoffman

Try a new caliper or at least change the seals. The seals are supposed to pull the pistons back and if they are old they won't. In addition, get a plain rotor, no holes, no slots which are not necessary these days. You know how to cut glass right? You use a tool to scratch a slot in it, then put the slot in tension by bending it and presto, the crack propagates.

95jersey

If you have your active handling on, the computer will use the brakes under hard cornering as it feels the car is going out of control. I used to use compeition mode and aruond this one track it would always cause the LF rotor to GLOW. I couldn't understand why that rotor would be so hot, but then I realized the active handling was pulsing the brakes very hard in one specific corner. If you want to continue to use AH, (which unless you are very experienced) I suggest you do, you need to do the following:

1) remove Eradispeed rotors
2) sell that junk on e-bay
3) buy NAPA rotors
4) crack as many as you want for $20!
5) buy some ducts

wtknght1

Bingo!!! We have a winner!!!!! Turn that crap off! Plus, the LF rotor is the one that cracks first on me because I like to trail brake...and most of the tracks we do are right hand turns...so the LF is generally able to brake more....and longer. As long as your car goes straight during acceleration and braking, then your calipers, pads, etc are probably OK. Just turn the comp mode off, drive smooth and keep replacing the rotors from either Rockauto.com or NAPA.

For the record, I run the Carbotechs with my T1 Vette (stock calipers, rotors, etc) and the front rotors normally last about 2 weekends (only 1 race though). These heavy cars and high speeds really take their toll on the rotors. I do have the DRM brake ducts.