Brake fade, how to prevent it........
04-21-2011, 12:37 PM
#61
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Thread Starter
Perhaps I missed it, but I didn't see if he mentioned whether the pedal was soft or firm when the car would not stop. Overheated fluid will give a soft pedal (and it gets progressively worse, so it doesn't sneak up on you), but overheated pads or glazed discs will give a firm pedal but little stopping power. On the Koni 997s (before going to motorsport ABS System) occasionally we'd get ultra-firm pedal with almost no stopping power. Overheating fresh SRF (even with PSM) is not easily done, and orange pagids are generally good for street tires, so I wonder if it was the PSM/ABS issue.
04-21-2011, 02:36 PM
#62
Rennlist Member
Pedal was firm with no stopping power....
.......................................................
Originally Posted by Adam@Autometrics
Perhaps I missed it, but I didn't see if he mentioned whether the pedal was soft or firm when the car would not stop. Overheated fluid will give a soft pedal (and it gets progressively worse, so it doesn't sneak up on you), but overheated pads or glazed discs will give a firm pedal but little stopping power. On the Koni 997s (before going to motorsport ABS System) occasionally we'd get ultra-firm pedal with almost no stopping power. Overheating fresh SRF (even with PSM) is not easily done, and orange pagids are generally good for street tires, so I wonder if it was the PSM/ABS issue.
.......................................................
Originally Posted by Adam@Autometrics
Perhaps I missed it, but I didn't see if he mentioned whether the pedal was soft or firm when the car would not stop. Overheated fluid will give a soft pedal (and it gets progressively worse, so it doesn't sneak up on you), but overheated pads or glazed discs will give a firm pedal but little stopping power. On the Koni 997s (before going to motorsport ABS System) occasionally we'd get ultra-firm pedal with almost no stopping power. Overheating fresh SRF (even with PSM) is not easily done, and orange pagids are generally good for street tires, so I wonder if it was the PSM/ABS issue.
so, larger rotors and "Blacks" solved the problem. generally, over heating the brakes can be solved by a technique, rather than a mechanical change, unless you are truely at the limit of the pad and rotor combo. I cant tell you of how many race days Ive been at, where a slower guy in the group will be boiling fluid, or complaining of lack of brakes, stopping power, fade, etc, only to see them with larger brakes, better pads all producing 2-4 seconds a lap slower times. Moving to blacks from ornanges, was a pretty significant change.
04-21-2011, 04:52 PM
#65
Mr. Excitement
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It is all in the missing or missed details. Rereading the OP I see onset was on the last lap and not discribed as getting worse over time. Paolo did the brakes go bad and come back with little warning or did you note them gettign weaker?
Ice mode is sudden onset. Heat related brake fade gets worse as you continue.
Ice mode is sudden onset. Heat related brake fade gets worse as you continue.
04-21-2011, 05:03 PM
#66
Rennlist Member
Thread Starter
It is all in the missing or missed details. Rereading the OP I see onset was on the last lap and not discribed as getting worse over time. Paolo did the brakes go bad and come back with little warning or did you note them gettign weaker?
Ice mode is sudden onset. Heat related brake fade gets worse as you continue.
Ice mode is sudden onset. Heat related brake fade gets worse as you continue.
In a prior session with an instructor in the car it did it once, at the end of the main straight, (but not so unresponsive as the last session), then it all went back to normal.
In the last session, the non-response was huge..... I came so close to the tire wall that I didn't want to chance it again, hence, packed up and left......
If anyone cares to share the cliff notes of "Ice mode", I would appreciate it....
04-21-2011, 05:13 PM
#67
Rennlist Member
I could be wrong, but I beleave it uses all four wheels. According the manual (http://www.porsche.com/all/media/pdf...ayman_PCNA.pdf page 63) it says it brakes each wheel independently.
You're right on the front brakes normally causing fade as they do the most stopping. Overall I don't think it matters which caliper boils the fluid - it all works off the same master cylinder. If you have dual MCs, then it might be different, but I'm guessing it would still create a soft pedal.
You're right on the front brakes normally causing fade as they do the most stopping. Overall I don't think it matters which caliper boils the fluid - it all works off the same master cylinder. If you have dual MCs, then it might be different, but I'm guessing it would still create a soft pedal.
04-21-2011, 05:15 PM
#68
Mr. Excitement
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Option #1: brakes went non-responsive suddenly, no prior warning......
In a prior session with an instructor in the car it did it once, at the end of the main straight, (but not so unresponsive as the last session), then it all went back to normal.
In the last session, the non-response was huge..... I came so close to the tire wall that I didn't want to chance it again, hence, packed up and left......
If anyone cares to share the cliff notes of "Ice mode", I would appreciate it....
In a prior session with an instructor in the car it did it once, at the end of the main straight, (but not so unresponsive as the last session), then it all went back to normal.
In the last session, the non-response was huge..... I came so close to the tire wall that I didn't want to chance it again, hence, packed up and left......
If anyone cares to share the cliff notes of "Ice mode", I would appreciate it....
I hate to say it but "search" is your best first move on this one. Lots of good info already typed.
04-21-2011, 05:46 PM
#69
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i have no idea. i was told once by somebody on a track that a good way to see how much PSM engages is to check wear on rea pads - if they go faster than fronts then it is PSM so i 'assumed' PSM kicks on rear only. apparently that was a wrong assumption based on what is in that PDF. interesting info, thanks.
04-21-2011, 05:46 PM
#70
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These products may pinpoint which brake component is getting overheated. The blue Thermax sticks to the caliper and the Tempilaq G paints onto the rotor's outside edge and/or metal backing of the pad. Manufactured by Tempil South Plainfield, NJ.
Last edited by sig_a; 05-29-2014 at 06:43 PM.
04-21-2011, 06:19 PM
#71
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Thread Starter
I guess I have been spoiled here on RL over the last few years.....
I have been accustumed to just ask a question and people would just spoon fee me the right answer....... now you want me to search?
Joking aside, thanks for all of you guys' help........
I am off to "search"......
04-21-2011, 06:50 PM
#72
Option #1: brakes went non-responsive suddenly, no prior warning......
In a prior session with an instructor in the car it did it once, at the end of the main straight, (but not so unresponsive as the last session), then it all went back to normal.
In the last session, the non-response was huge..... I came so close to the tire wall that I didn't want to chance it again, hence, packed up and left......
If anyone cares to share the cliff notes of "Ice mode", I would appreciate it....
In a prior session with an instructor in the car it did it once, at the end of the main straight, (but not so unresponsive as the last session), then it all went back to normal.
In the last session, the non-response was huge..... I came so close to the tire wall that I didn't want to chance it again, hence, packed up and left......
If anyone cares to share the cliff notes of "Ice mode", I would appreciate it....
04-21-2011, 06:55 PM
#73
Rennlist Member
What do you mean "search"?
I guess I have been spoiled here on RL over the last few years.....
I have been accustumed to just ask a question and people would just spoon fee me the right answer....... now you want me to search?
Joking aside, thanks for all of you guys' help........
I am off to "search"......
I guess I have been spoiled here on RL over the last few years.....
I have been accustumed to just ask a question and people would just spoon fee me the right answer....... now you want me to search?
Joking aside, thanks for all of you guys' help........
I am off to "search"......
Same for my kids; "Dad, why in the world would anyone waste their time going to a library for anything?"
04-21-2011, 07:25 PM
#74
uninformed gas bag
(contemplating on whether gas bag is one or two words)
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(contemplating on whether gas bag is one or two words)
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i have no idea. i was told once by somebody on a track that a good way to see how much PSM engages is to check wear on rea pads - if they go faster than fronts then it is PSM so i 'assumed' PSM kicks on rear only. apparently that was a wrong assumption based on what is in that PDF. interesting info, thanks.
04-21-2011, 09:40 PM
#75
Rennlist Member