Help! I keep cooking front rotors
11-05-2003, 04:47 PM
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Help! I keep cooking front rotors
I am running cryo treated slotted rotors, Hawk HP+ pads and stock calipers on 99 FRC with the regular (not Z06 style) ducts. I severely blued the outer 1/3 of the last set of rotors after 2 track days. This set has small heat stress cracks on the outer 1/3. One thing, I think the calipers have opened up, but the pad wear should wear to compensate for that. I've been told by the local guys not to run the Eradispeed rotors because of high failure rates on our local track. Most poeple here are not having problems with their rotors, I think they're just not getting as aggressive as I am. :D I do not have the money to get real brakes, Willwood, Alcon, etc. Which rotors and pads should I run for a daily driver, weekend tracker? Cooling, I know I need more cooling. Some of ya'll have mentioned multi-source brake cooling. Could I get some details and/or pics? I've got a track day on Nov 21 and I want to the brakes done by then.
11-05-2003, 05:20 PM
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Re: Help! I keep cooking front rotors (connellyh)
Mmmmm sounds pretty normal to me for track events. Yes you will blue them. Are you running an automatic trany? If so you will be harder on the brakes that the manual guys. The stress cracks you refer to are surface cracks and I can't think of a time that I have not seen them on a track car, no matter what rotors they are running. Porsche's, all of them get them. I admit, I don't know your driving style or what type of track events, but if it is open track, you are generating some significant heat!
the trick is to get on them hard and off them completely. I have run every rotor known to modern man and to be frank, I have gotten the best results with the eradis. I have had stock, VB Cryo treated, and eradis and on my second set of eradis.
If you are doing open track you will probably get a season out of them until you crack one completely. To date there are no reports I know of, of a rotor comming completely apart on the track or street.
I have come off the track with my rotors completely gun metal blue, and so hot I had to wait some significant time for them to cool enough to change back to my street tires and rims.
Even with the best of products the full blown race machines get one or two races to a set of rotors and pads, and most teams change after every race, and sometimes even after practice.
I find that a lot of people have expectations that the brakes will last forever like on a street machine, and that simply is not true. On Road corses and on autocross your brakes are a full 50% of your performance. And they are a throw-away item in professional competition.
If you only blued 1/3 of your rotors than one problem is the pads are not making full contact and that can cause the high heat you are talking about. You are only braking with 2/3 of your total pad surface. You may want to check and make sure the caliper sliders are free to center the caliper on the rotor. Some times they get too much grease on the pins and they vacuum lock and don't let the caliper center. I have heard rumors to the effect that some guys have had the stock calipers open up, but it has not happened to me and I have not personally seen it. I know of at least 10-20 guys doing open track with stock C5 calipers. I have burnt and melted piston boots and wiped slots completely from the face of the rotors, warped pistons and blown seals, but never opened one up, and I am on my second set of calipers. I got almost 75K miles on the origional set combined heavy track and street. I have 35K+ on my current set.
When I build my brakes, I do not use any of that goop stuff and at assembly, I make sure everything is hospital clean. I have found that a lot of people will use the anti noise stuff to try and keep competiton brakes quiet, but my rule is let them sing! As long as I know they are clean and seated and working right. that goop can cause as many problems as it fixes.
Just my 2 cents
jer
the trick is to get on them hard and off them completely. I have run every rotor known to modern man and to be frank, I have gotten the best results with the eradis. I have had stock, VB Cryo treated, and eradis and on my second set of eradis.
If you are doing open track you will probably get a season out of them until you crack one completely. To date there are no reports I know of, of a rotor comming completely apart on the track or street.
I have come off the track with my rotors completely gun metal blue, and so hot I had to wait some significant time for them to cool enough to change back to my street tires and rims.
Even with the best of products the full blown race machines get one or two races to a set of rotors and pads, and most teams change after every race, and sometimes even after practice.
I find that a lot of people have expectations that the brakes will last forever like on a street machine, and that simply is not true. On Road corses and on autocross your brakes are a full 50% of your performance. And they are a throw-away item in professional competition.
If you only blued 1/3 of your rotors than one problem is the pads are not making full contact and that can cause the high heat you are talking about. You are only braking with 2/3 of your total pad surface. You may want to check and make sure the caliper sliders are free to center the caliper on the rotor. Some times they get too much grease on the pins and they vacuum lock and don't let the caliper center. I have heard rumors to the effect that some guys have had the stock calipers open up, but it has not happened to me and I have not personally seen it. I know of at least 10-20 guys doing open track with stock C5 calipers. I have burnt and melted piston boots and wiped slots completely from the face of the rotors, warped pistons and blown seals, but never opened one up, and I am on my second set of calipers. I got almost 75K miles on the origional set combined heavy track and street. I have 35K+ on my current set.
When I build my brakes, I do not use any of that goop stuff and at assembly, I make sure everything is hospital clean. I have found that a lot of people will use the anti noise stuff to try and keep competiton brakes quiet, but my rule is let them sing! As long as I know they are clean and seated and working right. that goop can cause as many problems as it fixes.
Just my 2 cents
jer
11-05-2003, 05:27 PM
#3
Re: Help! I keep cooking front rotors (connellyh)
Do a search in the Autocross & Roadracing section and you will find a lot of info.
The basics are DRM front brake cooling ducts and the LG cooling adapters attached to the front brakes. Forum member John Shiels have a lot of info.
:cheers:
The basics are DRM front brake cooling ducts and the LG cooling adapters attached to the front brakes. Forum member John Shiels have a lot of info.
:cheers:
11-05-2003, 05:35 PM
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Re: Help! I keep cooking front rotors (BlueDragon)
My 99 is a 6sp (all 99 FRC's are 6sp). The heat stress cracks on this set of rotors are bigger and more pronuonced than usuall. I've run rotor with surface cracks in them on my C4 many times with no problems. The current crakcs make me nervous. When I mentioned that I blued the previous rotors, I did not mean just hot. They were blue after the cooled and I forgot to mention that both of them cracked all the way thru. Yes, track time severly decreases rotor life. However, I should get more than 1 or 2 days with a stock C5 running 3-4 20min sessions per day. The rotors are getting a full sweep during street use, but under track use they are getting more pressure on the outer 1/3. What have done about brake cooling?
11-05-2003, 07:10 PM
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Re: Help! I keep cooking front rotors (connellyh)
Hum! I would say the heat build up is due to that outer third problem and probably the main contributor to the cracking. Just for grins, check to make sure you have the rotors on the right sides. (I am not flaming ya here, just double checking because it is definately a cooling problem) and being that it is showing up on the outer third tells me that you are definately not getting cooling air and that is where it exits. Are those the Vette Brakes cryo rotors? They could have come from the manufacturer mis labled! If it is stickers. I still don't believe it is your calipers opening up, but I can't rule it out. But they are ok on the street???? (thats the hitch)
The uneven heating is definately causing those big cracks. I have only had those little surface spider cracks. I have had some friends crack all the way through, but that was after a lot of running with the spidercracks and they finally gave up the ghost.
One of the reasons I like the Eradis, is that they have a really improved cooling system over any of the other rotors out there.
I am serious, I had a set of performance friction 01 pads with eradi rotors and after an entire season of really beating them I wore the front rotors down to the point where the slots were gone. I had some minor spider cracks, but nothing close to all the way through.
We have the cooling ducts on ours. At frist I just ran a piece of dryer ducting and zip tied it in till I got the real thing.
The only other thing I can think of to check is the caliper sliders, make sure they are tight and not bent, and the caliper is free to center. But both sides do the same thing?? one side worse or better than the other?
Are you running a rebias front to rear. most of us run the Doug Rippie spring and it brings the rear up about 20% and keeps the rear down in hard braking and takes some of the load off the fronts. I now get perfectly even pad wear all around. Before I would wear out the front pads, and the rear were in the 50% range. Come to think of it, check out your rear brakes and make sure all your braking is not on the front only.
The only other thing I can think of is maybe bore wear on the pistons or seals. Hum come to think of it check the dust boots. I can't tell ya how many sets of those I have melted!
I think the brakes are the biggest maint item on the car when it comes to autocross and open track events.
Good luck, keep me posted on what you find.
Jer
The uneven heating is definately causing those big cracks. I have only had those little surface spider cracks. I have had some friends crack all the way through, but that was after a lot of running with the spidercracks and they finally gave up the ghost.
One of the reasons I like the Eradis, is that they have a really improved cooling system over any of the other rotors out there.
I am serious, I had a set of performance friction 01 pads with eradi rotors and after an entire season of really beating them I wore the front rotors down to the point where the slots were gone. I had some minor spider cracks, but nothing close to all the way through.
We have the cooling ducts on ours. At frist I just ran a piece of dryer ducting and zip tied it in till I got the real thing.
The only other thing I can think of to check is the caliper sliders, make sure they are tight and not bent, and the caliper is free to center. But both sides do the same thing?? one side worse or better than the other?
Are you running a rebias front to rear. most of us run the Doug Rippie spring and it brings the rear up about 20% and keeps the rear down in hard braking and takes some of the load off the fronts. I now get perfectly even pad wear all around. Before I would wear out the front pads, and the rear were in the 50% range. Come to think of it, check out your rear brakes and make sure all your braking is not on the front only.
The only other thing I can think of is maybe bore wear on the pistons or seals. Hum come to think of it check the dust boots. I can't tell ya how many sets of those I have melted!
I think the brakes are the biggest maint item on the car when it comes to autocross and open track events.
Good luck, keep me posted on what you find.
Jer
11-05-2003, 08:44 PM
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Re: Help! I keep cooking front rotors (connellyh)
It might be that your rear brakes are not assisting your fronts enough putting more strain on front. I dont know about auto cross cars but my 67 pro gas camaro had only front brakes and the front pads went real fast.
11-06-2003, 10:40 AM
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Re: Help! I keep cooking front rotors (BlueDragon)
Blue Dragon,
"Are you running a rebias front to rear. most of us run the Doug Rippie spring and it brings the rear up about 20% and keeps the rear down in hard braking and takes some of the load off the fronts. I now get perfectly even pad wear all around. Before I would wear out the front pads, and the rear were in the 50% range. Come to think of it, check out your rear brakes and make sure all your braking is not on the front only."
They is a decent amount of dust on the rears. They are working, but I don't know to what extent. I am running the stock bias, a new spring will be ordered today.
"The only other thing I can think of to check is the caliper sliders, make sure they are tight and not bent, and the caliper is free to center. But both sides do the same thing?? one side worse or better than the other?"
Sliders are free and both sides do the same thing to the same degree.
" seals. Hum come to think of it check the dust boots. I can't tell ya how many sets of those I have melted!"
Pistons, bores and boots are good. Tie rod boots are cooked. I'm gonna put some heat shielding around the new ones.
Are you running the regular Z06 ducts? Will they work with CCW 18" rims (285 tires)?
Thanks for all your help. :cheers:
"Are you running a rebias front to rear. most of us run the Doug Rippie spring and it brings the rear up about 20% and keeps the rear down in hard braking and takes some of the load off the fronts. I now get perfectly even pad wear all around. Before I would wear out the front pads, and the rear were in the 50% range. Come to think of it, check out your rear brakes and make sure all your braking is not on the front only."
They is a decent amount of dust on the rears. They are working, but I don't know to what extent. I am running the stock bias, a new spring will be ordered today.
"The only other thing I can think of to check is the caliper sliders, make sure they are tight and not bent, and the caliper is free to center. But both sides do the same thing?? one side worse or better than the other?"
Sliders are free and both sides do the same thing to the same degree.
" seals. Hum come to think of it check the dust boots. I can't tell ya how many sets of those I have melted!"
Pistons, bores and boots are good. Tie rod boots are cooked. I'm gonna put some heat shielding around the new ones.
Are you running the regular Z06 ducts? Will they work with CCW 18" rims (285 tires)?
Thanks for all your help. :cheers:
11-06-2003, 11:14 AM
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Re: Help! I keep cooking front rotors (connellyh)
I have a similar set up for road course events (see sig). You need to get air to your rotors with the Doug Rippie Motorsports brake ducts ($200). Takes a couple hours to install. Big help. Many of us use the stock rotors as they seem to last as well as the expensive heat treated, drilled, slotted variety from all the vendors. Stock rotors can be purchased from gmpartsdirect.com for $50 each. Napa has them for $25 each. After three or four single day track events the rotors will develop small cracks. I toss them when the cracks are longer than 1/2". This should be seen as a disposable cost to doing track events.
11-06-2003, 11:29 AM
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Re: Help! I keep cooking front rotors (Bill Benavitz)
iagree:
Yup, I have the Rippie ducts and bias, and I agree on the disaposable items. Ironic, I run the eradis on the street (more for the looks I guess) and the el cheapo NAPAs on the track. Like you say after a couple of tracke vents, I ditch the el-cheapo. I have not noticed that much of a difference in the actual performance of the rotors, I find it to all be in the pads. The PF01s will tear up a set of rotors and make a lot of noise in street use but on the track they are great. :
Yup, I have the Rippie ducts and bias, and I agree on the disaposable items. Ironic, I run the eradis on the street (more for the looks I guess) and the el cheapo NAPAs on the track. Like you say after a couple of tracke vents, I ditch the el-cheapo. I have not noticed that much of a difference in the actual performance of the rotors, I find it to all be in the pads. The PF01s will tear up a set of rotors and make a lot of noise in street use but on the track they are great. :
11-06-2003, 11:44 AM
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Re: Help! I keep cooking front rotors (BlueDragon)
I just ordered the bias srping and ducts from DRM and I'm gonna get the NAPA rotors (cheap enough). Are you slotting them? I have a milling machine so I can slot or dimple them. The pads I've been using are the Hawk HP+. Yep, they make tons of dust, squeel like school girl at boy band show, but they grab like mad on the track. Plus, a friend of mine is a Hawk dealer so I get them a bit cheaper than the PFC's.
11-06-2003, 04:46 PM
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Re: Help! I keep cooking front rotors (connellyh)
I have not slotted mine, but if you have a ball milling machine Gopher it! I got to look around to find someone I trust to mill them for me.
I am not sure with the new pads and materials that slotting is necessary, but I don't think it would hurt! some say it helps clean the pad surface. The origional intent was to release gassing, but that was with the older style pads.
Dimples??? Mmmmm don't know what they do. The holes are nice for cooling and maybe some weight savings.
Jer
I am not sure with the new pads and materials that slotting is necessary, but I don't think it would hurt! some say it helps clean the pad surface. The origional intent was to release gassing, but that was with the older style pads.
Dimples??? Mmmmm don't know what they do. The holes are nice for cooling and maybe some weight savings.
Jer
11-06-2003, 05:03 PM
#13
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Re: Help! I keep cooking front rotors (connellyh)
Stainless Steel pistons also help from DRM in the front. Lou LGM made me some spindle ducts which work great. He hasn't made anymore since. I think we should grab Louis and hold him hostage till he makes some :jester :lol: . The spindle ducts eliminated all wear on the rotors. After an entire set of PFC 01's and some on Wilwood J's. The metal never got hot enough to let the pads start to gouge. They did heat check and then split wide open with cracks from the hub to the edge. They were on the virge of exploding. This all happen in one session. I was checking them after each run. One had two cracks so I doubt I missed both. I have learned to temper my driving also.
With slicks you go faster in the corners and brake less. When I first started they told me the faster they go the less the brakes get used. I thought they were nuts but beleive it now. Air is free and you must use it! Cryo is a waste because the rotors get so hot I don't think it matters. My temp gun goes to 800 and when I put it on the rotors it blows it off the scale. Even the hub area is over 500 at times. Remember the rotors have a life even if they show no wear as they heat cycle.
With slicks you go faster in the corners and brake less. When I first started they told me the faster they go the less the brakes get used. I thought they were nuts but beleive it now. Air is free and you must use it! Cryo is a waste because the rotors get so hot I don't think it matters. My temp gun goes to 800 and when I put it on the rotors it blows it off the scale. Even the hub area is over 500 at times. Remember the rotors have a life even if they show no wear as they heat cycle.
