mark Posted October 12, 2008 Author Share Posted October 12, 2008 I'm not ready to start throwing money at the car yet. I do think caliper flex is part of the issue and have an idea or two about that. I'll wait to hear from wilwood and Dave to get there take on things. I don't understand floating rotors enough to get how they would help with caliper flex. I do understand how that design would greatly reduce rotor wear. This is an interesting read on caliper design. http://www.stoptech.com/tech_info/wp_monobloc.shtml The search continues for a fast, reliable, cheap track car. Perhaps perpetual motion would be an easier problem to solve. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 12, 2008 Share Posted October 12, 2008 I don't understand floating rotors enough to get how they would help with caliper flex. I do understand how that design would greatly reduce rotor wear. I don't think floating rotors would help with caliper flex at all, if that really is the issue. Have you removed the other caliper? I think whether it happens on one or both sides is pretty key to understanding whether you have a single bad caliper or a caliper that isn't up to the job. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted October 12, 2008 Share Posted October 12, 2008 It appears from the pictures that the bore wear is on the top and bottom of the bore, not in the direction of rotation where you would expect to see it. Possibly your (non-floating) rotor is getting cone-shaped due to thermal expansion being constrained by the thick rotor hat? This would cock the pistons in the bores to cause wear like that. Maybe a thinner cross-section aluminum or steel rotor hat would allow the rotor to grow and remain true. Willwood offers dual-layer pistons - mainly to prevent heat transfer to the fluid - maybe these may help your situation by allowing more mis-alignment. I ran Dave's old SLII 11.5" setup for years and never had a problem with them - but I was not using them anywhere near as hard as you do. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 I don't think floating rotors would help with caliper flex at all, if that really is the issue. Have you removed the other caliper? I think whether it happens on one or both sides is pretty key to understanding whether you have a single bad caliper or a caliper that isn't up to the job. The other side will get taken apart this week if I have time. I'll post the results. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 It appears from the pictures that the bore wear is on the top and bottom of the bore, not in the direction of rotation where you would expect to see it. Possibly your (non-floating) rotor is getting cone-shaped due to thermal expansion being constrained by the thick rotor hat? This would cock the pistons in the bores to cause wear like that.Maybe a thinner cross-section aluminum or steel rotor hat would allow the rotor to grow and remain true. Willwood offers dual-layer pistons - mainly to prevent heat transfer to the fluid - maybe these may help your situation by allowing more mis-alignment. I ran Dave's old SLII 11.5" setup for years and never had a problem with them - but I was not using them anywhere near as hard as you do. Thanks for the input. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 13, 2008 Share Posted October 13, 2008 Its most likely not just one thing because you're getting wear in two different places on the piston bores. Caliper flex is likely. When the Wilwoods flex they open up from the bottom and cause wear in the bottom of the piston bore. The cause of this flex is most likely heat buildup, not the overall strength of the caliper itself. You should have at least a 3" duct to the center of the rotor and a 2" duct to the caliper. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 I'll add another duct. I've got the 3 inch to the center. Do you think that caliper is worth trying to reuse? Quote Link to comment Share on other sites More sharing options...
johnc Posted October 13, 2008 Share Posted October 13, 2008 I would remove all the other calipers and inspect them before making any decisions - this might be a system problem not an individual part problem. You might also want to check your caliper mounting to make sure its not moving radially and check your rotors and hats per what Doug said above. If you're as fast as others say you are, its probably time for floating rotors. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted October 13, 2008 Share Posted October 13, 2008 A simple free body diagram of the forces involved in braking are all that is necessary to possibly point to the cause of the problem. One of the common problems in the automotive industry is to listen to what others are running which has nothing to do with your car, driving style, speeds and track. What works for others may still not work for you and your situation. Simply put outside of the forces you have temperature effects which in turn have a cause and effect on the clamping forces and resultant reactions. Seems that increased friction is desired resulting in less pressure, less pedal usage resulting in less heat or driving style change resulting in less heat added or possible increased brake cooling is required in your case. I watched a tv program where Dale Earnhardt had said that he loved his corvette over nascar cars due to the better brakes. It was his favorite car to drive on a road coarse. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 13, 2008 Share Posted October 13, 2008 I watched a tv program where Dale Earnhardt had said that he loved his corvette over nascar cars due to the better brakes. It was his favorite car to drive on a road coarse. Was that the C5R that he raced at the 24 Hours of Daytona, or a regular Vette? If it was the race car, the C5R really is in a whole other league with regards to brakes. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted October 13, 2008 Share Posted October 13, 2008 Seems that increased friction is desired resulting in less pressure, less pedal usage... Yup. Why I recommended a "grabbier" pad. Of course this assumes flex resulting from excessive pedal pressure. Quote Link to comment Share on other sites More sharing options...
bjhines Posted October 13, 2008 Share Posted October 13, 2008 2nd on the higher friction pads. I have had great results with highly aggressive friction compounds on several cars. I ran Hawk 9012 Blues on my BMW M3 this weekend and I love them. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 Thanks for the input guys. I now have several places to look at and items to address. I'll get it figured out. Would anybody here try to use that caliper again? Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 I currently have performance friction pads 01 compound. The car brakes very well when the fluid stays in the calipers. http://www.performancefriction.com/pages/compounds.htm Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 13, 2008 Share Posted October 13, 2008 Thanks for the input guys. I now have several places to look at and items to address. I'll get it figured out. Would anybody here try to use that caliper again? In thinking about this, if it didn't leak I don't know what the harm would be. Quote Link to comment Share on other sites More sharing options...
jt1 Posted October 13, 2008 Share Posted October 13, 2008 I wouldn't reuse that caliper. When you top the hill on the VIR backstraight at 160+, that's not one of the things you want to be worrying about. jt Edit: Earnhardt was talking about the C5R's carbon fiber brakes. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 I wouldn't reuse that caliper. When you top the hill on the VIR backstraight at 160+, that's not one of the things you want to be worrying about. jt Edit: Earnhardt was talking about the C5R's carbon fiber brakes. Excellent point! Quote Link to comment Share on other sites More sharing options...
Mikelly Posted October 13, 2008 Share Posted October 13, 2008 And those brakes are pretty much race only $15K brake components... The "regular" C5 and C6 calipers are considered a consumable by the corvette guys because the calipers spread on the press-fit pins and fail over time. My buddy that races in T1 replaces his calipers twice per season. Mike I wouldn't reuse that caliper. When you top the hill on the VIR backstraight at 160+, that's not one of the things you want to be worrying about. jt Edit: Earnhardt was talking about the C5R's carbon fiber brakes. Quote Link to comment Share on other sites More sharing options...
doublexl240z Posted October 13, 2008 Share Posted October 13, 2008 Mark, If you are going to go looking for some big brakes etc. Try musclemotorsports.com he is in NC and sells take off from the cup guys. He has some massive (read short track)Brembos, Wilwoods and AP for half the price of new. He has forged superlight for 160 a pair. PitstopUSA has them new for 165each. Quote Link to comment Share on other sites More sharing options...
mark Posted October 13, 2008 Author Share Posted October 13, 2008 Mark, If you are going to go looking for some big brakes etc. Try musclemotorsports.com he is in NC and sells take off from the cup guys. He has some massive (read short track)Brembos, Wilwoods and AP for half the price of new. He has forged superlight for 160 a pair. PitstopUSA has them new for 165each. I was there Saturday looking for seals for this caliper. I may go back and see what he has. Quote Link to comment Share on other sites More sharing options...
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