Beware of stock pads...
Apr 30, 2008, 10:03 AM
#1
Beware of stock pads...
.....and 30 minute track sessions! Haha The stock brakes (pads, rotors etc.) have been perfect at all the events so far this year. Until Monday, every session on track has been 20 mins or less, but on Monday at the AMS Track day @ Autobahn, we were running 30 minute sessions.
Everything was going very well, pads had more than 1/2 life left before tech in the morning, no brake fade (running Motul RBF600 fluid) and the pad was firm the entire session, until the last lap of the 2nd session. I could smell the brakes cooking so I started to let up, but as I braked for a turn, the pedal was gone. I had to pump it a few times, I thought it was just some boiled fluid, so I pulled off and pitted. I had a look at the passenger side brakes and saw there were major problems, I dont have any pics from the day of the event, so here are some from last night:
Grooved rotor:
Passenger side pad/backing plate/shield:
No more pad material
Backside of pad:
Steel backing plate, not Ti:
Comparison:
Pad from other side of caliper:
As of now, I am just having the front rotor turned, and going to run my Raybestos pads and flush in some fresh fluid. I am waiting for the X version of my package from Girodisc: http://girodisc.com/catalog/product_...roducts_id=239 Oh well, thought maybe some of you X owners might find this intersting. I think the pad just got past its thermal capacity and fell apart, so much for good stock brakes
Ryan
Everything was going very well, pads had more than 1/2 life left before tech in the morning, no brake fade (running Motul RBF600 fluid) and the pad was firm the entire session, until the last lap of the 2nd session. I could smell the brakes cooking so I started to let up, but as I braked for a turn, the pedal was gone. I had to pump it a few times, I thought it was just some boiled fluid, so I pulled off and pitted. I had a look at the passenger side brakes and saw there were major problems, I dont have any pics from the day of the event, so here are some from last night:
Grooved rotor:
Passenger side pad/backing plate/shield:
No more pad material
Backside of pad:
Steel backing plate, not Ti:
Comparison:
Pad from other side of caliper:
As of now, I am just having the front rotor turned, and going to run my Raybestos pads and flush in some fresh fluid. I am waiting for the X version of my package from Girodisc: http://girodisc.com/catalog/product_...roducts_id=239 Oh well, thought maybe some of you X owners might find this intersting. I think the pad just got past its thermal capacity and fell apart, so much for good stock brakes
Ryan
Apr 30, 2008, 10:43 AM
#3
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I thought that the OEM pads were bad for track days on any Evo? 8s and 9s had the same issue if I'm not mistaken.
But man...you obliterated those brakes lol!
But man...you obliterated those brakes lol!
Apr 30, 2008, 10:57 AM
#7
We had the same issue on our 08 STi. But switched to a BBK before it got to this point.
These cars are big and heavy, and even though the OEM Brembo Brakes are nice. By no means are they suited for racing on cars as heavy as the new EVO X or STi.
These cars are big and heavy, and even though the OEM Brembo Brakes are nice. By no means are they suited for racing on cars as heavy as the new EVO X or STi.
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Apr 30, 2008, 09:02 PM
#9
Ryan
Apr 30, 2008, 09:34 PM
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Sounds like you miraculously got some good track laps with those stockers'. Now your rotors are F'd and will be thinner/hotter after a 'turn..
I gotta' say that the very first time I hit the brakes during a test drive I knew the stock pads didn't belong on a track. Even after several heat cycles they were sucky and unresponsive. I'm sure everyone here will agree they are weak compared to a good set of pads, lines and fluid
I gotta' say that the very first time I hit the brakes during a test drive I knew the stock pads didn't belong on a track. Even after several heat cycles they were sucky and unresponsive. I'm sure everyone here will agree they are weak compared to a good set of pads, lines and fluid
Apr 30, 2008, 11:46 PM
#12
The thinner the pad, the more heat gets transferred to the caliper. The effect is exaggerated when using just the backing plates.
Evo brakes generally do not wear evenly on both sides of the caliper, so it is important to check the outside and the inside.
Having half the pad material left doesn't mean having half the useful track life left. This is especially the case for street pads which already operate at or beyond the top of their heat range on the track. Repeated braking from high speed demands a huge amount of heat dissipation, and it is vital not only to have enough wear surface, but enough material to absorb then dissipate heat between braking events without transferring it to the calipers, and then the brake lines.
It seems to me those calipers were doomed the minute it was decided to start a track day on worn pads regardless of the length of the sessions, as the pads likely had half the material left on the outside, significantly less than half on the inside, and possibly 1/3 to 1/8 of their useful life remaining at anywhere near the performance level possible for the first half of the wear. It's not great to start a track day with half-word track pads, let alone stockers.
It is important to check the pad wear between sessions, especially when it is known they are nearing the end of their service life. High-speed braking performance degradation is not linear, and the curve depends on a lot of different variables.
Glad you are using your X in its element!
Evo brakes generally do not wear evenly on both sides of the caliper, so it is important to check the outside and the inside.
Having half the pad material left doesn't mean having half the useful track life left. This is especially the case for street pads which already operate at or beyond the top of their heat range on the track. Repeated braking from high speed demands a huge amount of heat dissipation, and it is vital not only to have enough wear surface, but enough material to absorb then dissipate heat between braking events without transferring it to the calipers, and then the brake lines.
It seems to me those calipers were doomed the minute it was decided to start a track day on worn pads regardless of the length of the sessions, as the pads likely had half the material left on the outside, significantly less than half on the inside, and possibly 1/3 to 1/8 of their useful life remaining at anywhere near the performance level possible for the first half of the wear. It's not great to start a track day with half-word track pads, let alone stockers.
It is important to check the pad wear between sessions, especially when it is known they are nearing the end of their service life. High-speed braking performance degradation is not linear, and the curve depends on a lot of different variables.
Glad you are using your X in its element!
