Brake duct setup
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Originally Posted by zpeed' date='Jan 22 2009, 09:45 PM
Look like you aim your hose at the inside of the caliper/pad. PLEASE Correct me if I'm wrong. I can't see 3D on the picture. Do you have a problem of uneven cooling between inside pad and outside pad?
I see most of the ducting aim to the center of the rotor which air will go in the middle of rotor. Make it cool evenly.
I see most of the ducting aim to the center of the rotor which air will go in the middle of rotor. Make it cool evenly.
i am considering a further addition of ducting to double up on the ones shown to have a separate set cooling rotor for the front...and caliper for the rear.
keep the comments coming please ...its enlightening to hear your views...
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there is no need to run brake duct at rear. I ran temp paint on rotors. it doesn't get hot at rear at all.
tapering is from heat. you can either go to a higher MOT pads or run a brake duct. it is also why good multiple piston calipers have different piston bore sizes.
from Stoptech, http://www.stoptech.com/tech_info/wp_brake...elections.shtml
"TAPERED PAD WEAR
Similar to brake fade, there is more than one distinct type of tapered pad wear - radial taper and longitudinal taper.
1) If a caliper lacks stiffness and tends to "open" under clamping force, at elevated temperatures, the outboard surface (edge with the longest radius) of the pad with respect to the disc (axle), center will wear faster than the inboard (edge with the shortest radius), and the pad will be tapered in its cross section when viewed from the end. This is termed "radial taper".
2) The trailing area (portion) of the pad, to some extent "floats" on the entrapped gasses and particulate matter generated from the leading portion of the pad. The leading portion of the pad will always be hotter than the trailing portion and so will correspondingly, wear faster - resulting in a pad that is tapered when viewed from the edge. This phenomenon is termed "longitudinal taper".
The differential in heat generated across the pad surface, leading to trailing, is characteristic regardless of caliper and pad design. This is why all racing calipers and most high performance street calipers have differential piston bores. Most high performance pads also feature a tapered leading edge.
3) In the case of new very thick pads like the type used for endurance racecars, longitudinal taper will sometimes occur because the pad literally tips inward at an angle against the disc during "off brake" conditions. When this happens, there is a small amount of force pushing the pad leading edge in the direction of the disc as a result of the contact and the friction generated. At the same time, the trailing side of the pad is wedged back into the corner of the pad cavity in the caliper and against the abutment plate, which further promotes contact at the leading edge. This situation is exaggerated with new thick pads since the increased offset of the pad friction surface from the backing plate, results in a relatively larger constant force vector in the direction of the disc.
4) Taper can also be seen where the disc is solidly fixed to the hat or where the hat and disc are one piece. In either case, the taper created will appears as more wear on the outer diameter of the outside pad, and the inner diameter of the inside pad. This is due to operating the brakes at high temperature and the resulting thermal expansion forces on the annular outer ring structure of the disc called the friction plates. The center of the disc or hat limits the expansion of the outer structure on only one side where it is joined, typically at the outside friction plate. As a result, the disc cones so that it is concave as viewed from the outside (See also "Floating Discs"). Subsequently due to the coning, the pad contacts unevenly when the brakes are applied or remains in contact with the disc in the regions mentioned and even higher temperatures and wear are the result."
tapering is from heat. you can either go to a higher MOT pads or run a brake duct. it is also why good multiple piston calipers have different piston bore sizes.
from Stoptech, http://www.stoptech.com/tech_info/wp_brake...elections.shtml
"TAPERED PAD WEAR
Similar to brake fade, there is more than one distinct type of tapered pad wear - radial taper and longitudinal taper.
1) If a caliper lacks stiffness and tends to "open" under clamping force, at elevated temperatures, the outboard surface (edge with the longest radius) of the pad with respect to the disc (axle), center will wear faster than the inboard (edge with the shortest radius), and the pad will be tapered in its cross section when viewed from the end. This is termed "radial taper".
2) The trailing area (portion) of the pad, to some extent "floats" on the entrapped gasses and particulate matter generated from the leading portion of the pad. The leading portion of the pad will always be hotter than the trailing portion and so will correspondingly, wear faster - resulting in a pad that is tapered when viewed from the edge. This phenomenon is termed "longitudinal taper".
The differential in heat generated across the pad surface, leading to trailing, is characteristic regardless of caliper and pad design. This is why all racing calipers and most high performance street calipers have differential piston bores. Most high performance pads also feature a tapered leading edge.
3) In the case of new very thick pads like the type used for endurance racecars, longitudinal taper will sometimes occur because the pad literally tips inward at an angle against the disc during "off brake" conditions. When this happens, there is a small amount of force pushing the pad leading edge in the direction of the disc as a result of the contact and the friction generated. At the same time, the trailing side of the pad is wedged back into the corner of the pad cavity in the caliper and against the abutment plate, which further promotes contact at the leading edge. This situation is exaggerated with new thick pads since the increased offset of the pad friction surface from the backing plate, results in a relatively larger constant force vector in the direction of the disc.
4) Taper can also be seen where the disc is solidly fixed to the hat or where the hat and disc are one piece. In either case, the taper created will appears as more wear on the outer diameter of the outside pad, and the inner diameter of the inside pad. This is due to operating the brakes at high temperature and the resulting thermal expansion forces on the annular outer ring structure of the disc called the friction plates. The center of the disc or hat limits the expansion of the outer structure on only one side where it is joined, typically at the outside friction plate. As a result, the disc cones so that it is concave as viewed from the outside (See also "Floating Discs"). Subsequently due to the coning, the pad contacts unevenly when the brakes are applied or remains in contact with the disc in the regions mentioned and even higher temperatures and wear are the result."
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From: Wylie, TX
Originally Posted by bellwilliam' date='Jan 23 2009, 11:40 AM
there is no need to run brake duct at rear. I ran temp paint on rotors. it doesn't get hot at rear at all.
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Originally Posted by bellwilliam' date='Jan 23 2009, 10:45 AM
true, but they have to be REALLY mismatched. as long as front and rear pads are close, there would be no need to run rear duct. in all my temp paint test, rear runs 200-400F cooler. this is all on RWD. on FWD, I would imagine rear pads would never ever get hot enough.
if you are running say race pad XP12 on front and stock pads on rear. you have much bigger problem than overheating the rear. when brake is cold, you would lock up rear. when warmed, you would lock up front, and so forth. it is always a good idea to run front and rear pads as close as possible. you get consistent characteristic throughout.
if you are running say race pad XP12 on front and stock pads on rear. you have much bigger problem than overheating the rear. when brake is cold, you would lock up rear. when warmed, you would lock up front, and so forth. it is always a good idea to run front and rear pads as close as possible. you get consistent characteristic throughout.
my friend has run a setup without ducting on the rears with stock pads and the pads sort of disintegrated. i went from 50% to nothing in one track session. i am not sure if it simply the pads cannot take such temps (meaning i should have gotten aftermarket pads) or the result of heat soak to the disc.
i will be running ferodos on the rear and seeing how the wear rate pans out...
bellwilliam: i may be using rotor temp paint as well to ascertain effectiveness of the ducting soon.
one question would be, wat are the typical track temps that you experience? i believe the necessity of rear ducting may also be dependent on the conditions of the track.
i'll probably chk out the subsequent taper i experience with a fresh set of pads to see how the setup can be improved. thanks for the info link....
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Originally Posted by honda9krpm' date='Jan 21 2009, 06:12 PM
Looks good. What duct size did you use?
would go bigger but clearance at full lock was a consideration. so far it has proven effective though...
