[Z06] 2 Piece Rotors Warped? Ideas? Help
11-26-2014, 09:20 PM
#22
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Bill,
Curious about your issue, did you run any heat indicator compound on the rotors? Cooling is a really big thing especially on the light weight rotor. Coleman makes another rotor that we use for HD application we sell that has a .360 thick face vs. a .250 that the light one has. I believe that Robert @ AFX only uses the .360 on his since about 99% of his sales are on race cars. What mode do you run your car in, I see street cars having issues every so often but it always comes back to the Active Handling. On all out race cars where this has been disconnected the rotors last all season or at least until they are timed out. On a full race car I still would want the HD rotor unless there is allot of cooling. I personally don't like the stock locations on the brake inlets, I like the fog light though and you should have had great cooling right there. I run a 3" duct on our setups. Johhny Miller the Trans Am driver was with us with his T1 car at VIR when Landstra cracked a rotor. He also thought is was a cooling issue coupled with Active handling. He was explaining that on the TA car they ran Coleman 12" rotors but had 3 4" duct going to each rotor or cooling. I think all or most of the issues lead back to the cooling of the rotor and it may be why none of the race cars have any issues with them.
Curious about your issue, did you run any heat indicator compound on the rotors? Cooling is a really big thing especially on the light weight rotor. Coleman makes another rotor that we use for HD application we sell that has a .360 thick face vs. a .250 that the light one has. I believe that Robert @ AFX only uses the .360 on his since about 99% of his sales are on race cars. What mode do you run your car in, I see street cars having issues every so often but it always comes back to the Active Handling. On all out race cars where this has been disconnected the rotors last all season or at least until they are timed out. On a full race car I still would want the HD rotor unless there is allot of cooling. I personally don't like the stock locations on the brake inlets, I like the fog light though and you should have had great cooling right there. I run a 3" duct on our setups. Johhny Miller the Trans Am driver was with us with his T1 car at VIR when Landstra cracked a rotor. He also thought is was a cooling issue coupled with Active handling. He was explaining that on the TA car they ran Coleman 12" rotors but had 3 4" duct going to each rotor or cooling. I think all or most of the issues lead back to the cooling of the rotor and it may be why none of the race cars have any issues with them.
I almost always turned off AH unless I forgot to turn it off. However, it didn't interfere all that much when I left it on. Sometimes it could take 3 or 4 laps around the Glen before it activated. Same with TC. The vast majority of the time everything was turned off when I left the garage. About a year before I stopped using the fog light inlets I had stopped using tire pressure sensors in my wheels and I would pull the steering sensor connector apart which stopped AH from turning on and limiting my corner speed to 55 mph. I never noticed a change in brake characteristics due to not having any AH.
When I modded my stock brake ducts I added inlets from the fog lights while keeping air intake from the under bumper inlets. This is what the ducts looked like after my mods.
The duct hose went from the stock duct to the back of the air intake duct I installed in place of the fog lights. The 3 inch tube at the other end was connected with the Lambert 3 inch spindle ducts by a 3 inch hose.
This is what the fog light inlet ducts looked like with the modded duct connected to them.
I had thought the fog light inlets would get more air to the rotors but they didn't seem to help. I still had brake fluid and rotor cracking issues.
This setup was on the car when this AFX/Coleman rotor experienced this failure. It was the beginning of the season at the Glen and I was able to do 8 track days over an 11 day period. The rotor failed on day 6. You can clearly see where the inside face has separated from the vanes.
Now that I look at the picture I see the description that I put in the previous post is a little erroneous. There are two cracks to the faces of the rotor and the inside face is the part that separated from the vanes. However, when I was trying to figure out what was initially causing the thumping they weren't cracked on the face yet.
I removed the fog light duct inlets last year when I decided I wanted to drive to Sebring from upstate NY to attend the NCM HPDE. I never put them back on and then at last year's Corvettes at Carlisle I was talking to a GM engineer about the C7 aero and his personal C6Z. The discussion got around to brake cooling inlets and he said the foglight location is a low pressure area and not a very good place to pick up cooling air. He said the best place would be in the radiator intake in the front fascia or to stay with the inlets under the fascia. That is when I decided to check the air dam and found out it needed replacing. The bottom edge reinforces the air dam and helps prevent it from bending inward. My bottom edge was worn off and the air dam was quite flexible. Things improved with the new air dams installed and properly tied to the center air dam. That is when I went from my modded stock ducts to the LG modded ducts. The LGs were cleaner inside and didn't interfere with air flow as much.
As I said in my previous post when I got everything back to stock air intake under the bumper, the new air dams and used some Aluminized Duct tape to block off a hole in the back of the Lambert Spindle Ducts I haven't had any more brake boiling or brake rotor cracking issues although my Wilwoods are pretty close to cracking. That was at the beginning of Sept. 2013. I put 5 track days on the brakes at the Glen (hard on brakes) last year, 2 days at Sebring and 5 days at VIR this year.
It was nice after 4 years of struggling with cracked brake rotors, boiled fluid and lots of consumable parts to be able to go so long with only an occasional brake bleed and changing of pads.
Bill
11-26-2014, 09:52 PM
#23
Intermediate
Thread Starter
Well...after a number of unanswered phone calls and emails, I sent an email to the president of ZIP Corvette. He was very nice. He acknowledged and apologized for the poor customer service. Very nice gentleman.
After this, I was finally able to speak to someone at Zip Corvette. I will not say their name.
Essentially, I was told that despite me running the brake cooling ducts, the rotors were overheated in 1sesion of the bed in protocol and 3 laps until I felt they were too unsafe to continue.
Zip admitted that they knew there was a problem and I was told quote, "We first learned about this problem with the rotors in 2007 with the first C6 Z06's began running at the track. These rotors have less material to make them light weight, so they can get overheated and warped easily." "We have seen them actually cracked from over heating." As I was hearing this, I got even more upset thinking that they knew about this problem and I risked my safety and my car with a known problem!!!! This is not a reflection of Coleman rotors as they are made specifically for Zip Corvette per their requests.
Interesting that on the description, it doesn't say anything about less material or thickness, but says "OE replacement for the demanding Corvette enthusiast."
Anyways, I was told that they were coming out with an "intermediate rotor" that had more thickness and should be less likely to get overheated and warped. They said that I could send them more money and they would send those to me. As you could imagine, I declined.
I will let you know the final outcome. As the previous posts say "We do the right thing for our customers." I did not even ask what they were going to do as a final decision, but we will see how they respond.
After this, I was finally able to speak to someone at Zip Corvette. I will not say their name.
Essentially, I was told that despite me running the brake cooling ducts, the rotors were overheated in 1sesion of the bed in protocol and 3 laps until I felt they were too unsafe to continue.
Zip admitted that they knew there was a problem and I was told quote, "We first learned about this problem with the rotors in 2007 with the first C6 Z06's began running at the track. These rotors have less material to make them light weight, so they can get overheated and warped easily." "We have seen them actually cracked from over heating." As I was hearing this, I got even more upset thinking that they knew about this problem and I risked my safety and my car with a known problem!!!! This is not a reflection of Coleman rotors as they are made specifically for Zip Corvette per their requests.
Interesting that on the description, it doesn't say anything about less material or thickness, but says "OE replacement for the demanding Corvette enthusiast."
Anyways, I was told that they were coming out with an "intermediate rotor" that had more thickness and should be less likely to get overheated and warped. They said that I could send them more money and they would send those to me. As you could imagine, I declined.
I will let you know the final outcome. As the previous posts say "We do the right thing for our customers." I did not even ask what they were going to do as a final decision, but we will see how they respond.
11-26-2014, 11:37 PM
#24
I'm still amazed you warped rotors while just bedding them. I always thought warping comes from rapid heating and cooling cycles and is rare. But hey, if they say they were actually warped, what can you do?
I guess you need to just call it a wear item and move on.
I don't track my car near what Bill does, but I've had reasonable luck with the stock brakes. I just had them rebuilt with SS pistons. I think the one thing they do do is wear pads unevenly toward the end, but by then I replace them so they seem to be not worth it to replace calipers for me. Maybe the rebuild will even that out?? But everyone drives in a different way, and tracks vary...
Thanks all for the info.
I guess you need to just call it a wear item and move on.
I don't track my car near what Bill does, but I've had reasonable luck with the stock brakes. I just had them rebuilt with SS pistons. I think the one thing they do do is wear pads unevenly toward the end, but by then I replace them so they seem to be not worth it to replace calipers for me. Maybe the rebuild will even that out?? But everyone drives in a different way, and tracks vary...
Thanks all for the info.
12-11-2014, 06:27 PM
#25
Platinum Supporting Vendor
First, I thought that the allegation of Zip selling a defective or dangerous part needs to be answered.
Zip stands behind all the parts we sell, especially something we manufacture. We spent years developing these rotors with Performance AFX before the first set was ever up for sale. We use Coleman rings, they provide the majority of all brake rings to every form of motorsports. The brake ring that we use on this particular set is one Coleman’s HD rings for the 355/32mm rings. We also use a heavier ring in the 355/32 mm class for our floating rotor that only became available in 09 from them.
The rotors that were returned were ruined by heat, no matter what rotor is on a car, if you are going to run with active handling and stock cooling ducts you are going to overheat the rotors to the point of warping or cracking. I have seen the best Brembo’s break from heat caused by Active handling and in adequate cooling. Our rotors are no different, we offer lighter weight and better braking capabilities, however if Active Handling and no cooling is present, especially on the lighter weight rotors heat will be an issue. Heat is always the number one cause of a failure from Race Cars to Space flight. I will enclose some photos of the said rotors that were returned for warping and you can see the nice blue in the rotor. They were not sent out like that, each rotor is turned to size so for a rotor to be warped it would have to have been off on the Lathe. The bolt pattern does not make and issue on these, however they are torqued in a sequence and the bolt torque is 110 Inch pounds. That is just beyond hand tight. The strength in these NAS bolts is the shear on the shoulder, not the clamping load of the bolt.
We returned the money to this customer because there seems to have been more of an issue with communication than with the part itself. Hopefully he will understand what I have explained to him so in his next outing with his car there will be no issues.
I will post the photos this evening as they are on my other laptop that is at home. These particular rotors are being converted over to floating rotors, if there is someone interested in them I will make you a great deal. The hats look really good and we will clean them up, the floating rotors and all associated parts will be new. Please email me though if you are interested, I am not on the forum every day.
Thank You
Justin Abbott
jabbott@zip-corvette.com
Zip stands behind all the parts we sell, especially something we manufacture. We spent years developing these rotors with Performance AFX before the first set was ever up for sale. We use Coleman rings, they provide the majority of all brake rings to every form of motorsports. The brake ring that we use on this particular set is one Coleman’s HD rings for the 355/32mm rings. We also use a heavier ring in the 355/32 mm class for our floating rotor that only became available in 09 from them.
The rotors that were returned were ruined by heat, no matter what rotor is on a car, if you are going to run with active handling and stock cooling ducts you are going to overheat the rotors to the point of warping or cracking. I have seen the best Brembo’s break from heat caused by Active handling and in adequate cooling. Our rotors are no different, we offer lighter weight and better braking capabilities, however if Active Handling and no cooling is present, especially on the lighter weight rotors heat will be an issue. Heat is always the number one cause of a failure from Race Cars to Space flight. I will enclose some photos of the said rotors that were returned for warping and you can see the nice blue in the rotor. They were not sent out like that, each rotor is turned to size so for a rotor to be warped it would have to have been off on the Lathe. The bolt pattern does not make and issue on these, however they are torqued in a sequence and the bolt torque is 110 Inch pounds. That is just beyond hand tight. The strength in these NAS bolts is the shear on the shoulder, not the clamping load of the bolt.
We returned the money to this customer because there seems to have been more of an issue with communication than with the part itself. Hopefully he will understand what I have explained to him so in his next outing with his car there will be no issues.
I will post the photos this evening as they are on my other laptop that is at home. These particular rotors are being converted over to floating rotors, if there is someone interested in them I will make you a great deal. The hats look really good and we will clean them up, the floating rotors and all associated parts will be new. Please email me though if you are interested, I am not on the forum every day.
Thank You
Justin Abbott
jabbott@zip-corvette.com
Last edited by Zip Corvettes; 12-11-2014 at 06:42 PM.
12-11-2014, 06:46 PM
#26
Race Director
I have 4" brake ducts coming in from the sides of the grill opening into the stock ductwork and then " AFX ducts out to the rotors. Once I did that, my brake cooling became much less of an issue although I still have the HD Colemen rotors get badly heat checked after 4-6 track days. I haven't had one crack yet as I replace them before that happens.
12-11-2014, 08:44 PM
#27
Platinum Supporting Vendor
I have 4" brake ducts coming in from the sides of the grill opening into the stock ductwork and then " AFX ducts out to the rotors. Once I did that, my brake cooling became much less of an issue although I still have the HD Colemen rotors get badly heat checked after 4-6 track days. I haven't had one crack yet as I replace them before that happens.
You should be getting more than 4-5 track days, but I don't know what you are running. Coleman makes a bunch of different rotors. Are you disconnecting your AH?
12-11-2014, 08:57 PM
#29
Platinum Supporting Vendor
I have a video but I guess I have to upload that to youtube first. It is a runout gauge on the rotor showing about .0055 of runout. More than what I would want but not as much as some stock setups.
12-11-2014, 10:02 PM
#30
You guys clearly know how to set stuff up. But I still think that rotor above this post looks thin compared to Dearborn's, which look like my Coleman HD's. The warping issue seems plausible with thin rotors, but I still don't see how AH and some laps can warp a set of rotors that are of this quality. I ran my stock rotors hard with AH on (rarely went on, really) and they never warped with stock pads and XP8's. The Xp8 rear / enduro combo now is holding up well as well.
If the runout is within spec, maybe the customer was just sensitive.. I have "some" pedal shake in my brakes, worse when not hot, but just live with it or I would be always buying new.
So the above rotors are the ones off the car that are "minimally warped?"
If the runout is within spec, maybe the customer was just sensitive.. I have "some" pedal shake in my brakes, worse when not hot, but just live with it or I would be always buying new.
So the above rotors are the ones off the car that are "minimally warped?"
12-11-2014, 11:06 PM
#31
Platinum Supporting Vendor
You guys clearly know how to set stuff up. But I still think that rotor above this post looks thin compared to Dearborn's, which look like my Coleman HD's. The warping issue seems plausible with thin rotors, but I still don't see how AH and some laps can warp a set of rotors that are of this quality. I ran my stock rotors hard with AH on (rarely went on, really) and they never warped with stock pads and XP8's. The Xp8 rear / enduro combo now is holding up well as well.
If the runout is within spec, maybe the customer was just sensitive.. I have "some" pedal shake in my brakes, worse when not hot, but just live with it or I would be always buying new.
So the above rotors are the ones off the car that are "minimally warped?"
If the runout is within spec, maybe the customer was just sensitive.. I have "some" pedal shake in my brakes, worse when not hot, but just live with it or I would be always buying new.
So the above rotors are the ones off the car that are "minimally warped?"
This rotor was the heaviest that Coleman offered in the 335/32 up until 09, they have one now that has less air gap, which means thicker sides. This is the rotor that we have run on the race cars which normally last an entire season, however they have cooling.
The issue with AH is that it all depends on the driver. Once the AH is activated it stays on until the car is going straight. When I mean on, it is squeezing brake calipers individually to get the car straight, If this is happening the entire way around the track you are constantly building heat in the rotor and then to top it off you don't have adequate cooling. It will take a rotor out pretty quickly. This is only on the ZO6 with this light weight rotor. The smaller rotors for the C5,C6 have smaller rotors with smaller air gaps. There are also on a very small amount of people that have an issue with this, most of them are cooling or turning off AH. You are probably running with traction control off or in competitive mode which also changes the algorithm of AH, this particular car was running with everything turned on.
If you measure your air gap you will know if your rotors are have thicker sides, the rotor width is 32mm.
As far as the runout, it is minimal and I would not run them. I measure a new one and it was <.001
Last edited by Zip Corvettes; 12-11-2014 at 11:10 PM.
12-11-2014, 11:08 PM
#32
Platinum Supporting Vendor
Yes, those are the rotors, you can see the heat in them, they are blue with a constant blue band around them.
This rotor was the heaviest that Coleman offered in the 335/32 up until 09, they have one now that has less air gap, which means thicker sides. This is the rotor that we have run on the race cars which normally last an entire season, however they have cooling.
The issue with AH is that it all depends on the driver. Once the AH is activated it stays on until the car is going straight. When I mean on, it is squeezing brake calipers individually to get the car straight, If this is happening the entire way around the track you are constantly building heat in the rotor and then to top it off you don't have adequate cooling. It will take a rotor out pretty quickly. This is only on the ZO6 with this light weight rotor. The smaller rotors for the C5,C6 have smaller rotors with smaller air gaps. There are also on a very small amount of people that have an issue with this, most of them are cooling or turning off AH. You are probably running with traction control off or in competitive mode which also changes the algorithm of AH, this particular car was running with everything turned on.
If you measure your air gap you will know if your rotors are have thicker sides, the rotor width is 32mm.
This rotor was the heaviest that Coleman offered in the 335/32 up until 09, they have one now that has less air gap, which means thicker sides. This is the rotor that we have run on the race cars which normally last an entire season, however they have cooling.
The issue with AH is that it all depends on the driver. Once the AH is activated it stays on until the car is going straight. When I mean on, it is squeezing brake calipers individually to get the car straight, If this is happening the entire way around the track you are constantly building heat in the rotor and then to top it off you don't have adequate cooling. It will take a rotor out pretty quickly. This is only on the ZO6 with this light weight rotor. The smaller rotors for the C5,C6 have smaller rotors with smaller air gaps. There are also on a very small amount of people that have an issue with this, most of them are cooling or turning off AH. You are probably running with traction control off or in competitive mode which also changes the algorithm of AH, this particular car was running with everything turned on.
If you measure your air gap you will know if your rotors are have thicker sides, the rotor width is 32mm.
12-12-2014, 12:40 AM
#33
Race Director
Heat checking is not so much an issue as long as they are not turning into cracks. Getting ducts in the radiator shroud is the ideal place as that is high pressure air, that is where I run the race car ducts.
You should be getting more than 4-5 track days, but I don't know what you are running. Coleman makes a bunch of different rotors. Are you disconnecting your AH?
You should be getting more than 4-5 track days, but I don't know what you are running. Coleman makes a bunch of different rotors. Are you disconnecting your AH?
Sorry about the earlier comment. Yes I get closer to 10 track days on the rings, just 4-5 on the Cobalt XR2 pads in the front. I got fewer days on the lightweight rings but now run the heavier rings, but the rings/hats still save 6# per rotor over stock.
