996 Turbo brake system failure during track-day.
#31
Originally Posted by BobbyC
Roadsleeper - hope that you can get to the bottom of what caused this perceived or real brake failure and share your findings with us. This is relevant to all of us who drive a 996TT.
And please ignore any disparaging remarks about your ability to communicate in English...you're doing just fine. There's always an idiot out there who thinks he knows better!
And please ignore any disparaging remarks about your ability to communicate in English...you're doing just fine. There's always an idiot out there who thinks he knows better!
And what's the emoticon for "obsequious" ... I guess you had to use "banghead" instead ... ?
#32
Race Director
Join Date: Oct 2004
Location: KC ex pat marooned in NY
Posts: 13,005
Likes: 0
Received 17 Likes
on
17 Posts
Bobby, Tom's right on this one. I had my fluid boil at limerock, my brake wear light came on and my pedal felt slightly mushy, I called it a day. When I took it down that night, the sensor wires had melted and the fluid smelled burn't. So, yes you will get some warning, but whether one is astute enough to pick up on it is another matter.
Chris
btw Are you going to the glen, see ya there!
Chris
btw Are you going to the glen, see ya there!
#33
Rennlist Member
Originally Posted by C4S Surgeon
Bobby, Tom's right on this one. I had my fluid boil at limerock, my brake wear light came on and my pedal felt slightly mushy, I called it a day. When I took it down that night, the sensor wires had melted and the fluid smelled burn't. So, yes you will get some warning, but whether one is astute enough to pick up on it is another matter.
Chris
btw Are you going to the glen, see ya there!
Chris
btw Are you going to the glen, see ya there!
BTW, regarding this brake failure business...check out the thread under Racing "Brake Failure" and you'll hear some stories. I'm not taking any chances with brakes (especially at a hard braking track like the Glen) so even though I'm running with my PCCBs I put in SRF fluid and Pagid race pads.
Yup, I'll probably be going back to the Glen Jun 19-20 with PCA SCH. See ya there...cheers!
#34
Rennlist Member
Ok, I'm jealous with all the NE track talk, I'm a born and raised Philly boy and I may have to go on a road trip to come and play!!
The Chin events are excellent in Florida as well. My favorite part is that they allow passengers! Track time is almost unlimited and it is at that kind of event where I have to remind myself to get off the track, I usually do it by time and limit myself to about 45 minutes.
How long have you guys run hard on the track at one time? Certainly good test of brakes, I also run what Bobby does sans PCCB. Have added the cup ducts and so far really not even any fade.
The Chin events are excellent in Florida as well. My favorite part is that they allow passengers! Track time is almost unlimited and it is at that kind of event where I have to remind myself to get off the track, I usually do it by time and limit myself to about 45 minutes.
How long have you guys run hard on the track at one time? Certainly good test of brakes, I also run what Bobby does sans PCCB. Have added the cup ducts and so far really not even any fade.
#35
Drifting
Join Date: Jun 2001
Location: Houston, Texas
Posts: 3,199
Likes: 0
Received 0 Likes
on
0 Posts
I agree with Tom, Chris and the others on this one. As good as a Turbo, or ANY Porsche, is at the track the cars must be maintained in a proper fashion to perform at their high level. From the way it sounds, the car was not well prepared for the track and cooked his brake fluid. Either worn down pads or old/ moisture contaminated fluid are the usual suspects. I change and bleed my fluid and pads before any track event, it's the only safe way to go.
I'm truly sorry to hear that the car was trashed, I hope the driver was OK. But sorry Dude," you takes your car to the track and you takes your chances". Anything can happen at the track, even if your car is prepared perfectly somebody can lose an engine right in front of your eyes then you're screwed. You can't expect Porsche to pay for the car when it was crashed at the race track.
slight highjack...Tom I'm really warming up to Speed Yellow in my new TT how has it been for you? Thanks
Doug
I'm truly sorry to hear that the car was trashed, I hope the driver was OK. But sorry Dude," you takes your car to the track and you takes your chances". Anything can happen at the track, even if your car is prepared perfectly somebody can lose an engine right in front of your eyes then you're screwed. You can't expect Porsche to pay for the car when it was crashed at the race track.
slight highjack...Tom I'm really warming up to Speed Yellow in my new TT how has it been for you? Thanks
Doug
#37
Rennlist Member
Blame anesthesia! Really who does that! LOL
Doug the Speed yellow TT has been the most awesome looker and performer you could imagine!!!!
BTW I am putting in GT3 seats and if you dont have the speed yellow sport seats pm me!!
Doug the Speed yellow TT has been the most awesome looker and performer you could imagine!!!!
BTW I am putting in GT3 seats and if you dont have the speed yellow sport seats pm me!!
#38
I remember something that happened to me 10 years on my race car back then, a rubber brake hose (we were not alowed to fit ss braided) just blew some of the inbedded nylon braid but the rubber was intact meaning nothing could be seen from the outside and only under load a bubble would pop from the right front hose and this meant the pedal went down with little efford...
#39
Rennlist Member
Kiko,
After that occurred, did it happen each and every time you used the brakes? Could you see it happen when the car was standing still and the brakes applied? AS
After that occurred, did it happen each and every time you used the brakes? Could you see it happen when the car was standing still and the brakes applied? AS
#40
Yes, it took us so long to figure out but eventually we managed to trace the problem by replicating hard braking with the wheels off. As soon as you take your foot the hose comes back to shape, apparently this is not that odd and the explanation is very simple: The inner nylon braid just gives up.
#41
Instructor
Join Date: Nov 2007
Location: Western USA
Posts: 100
Likes: 0
Received 0 Likes
on
0 Posts
I have "boiled the fluid" on a track day, makes for work in the pit area, and yes the brake fades so far it seems they don't work at all. change your brakes or change you driving style. I found that having new pads and fluid, and breaking them in before an event prevents problems, have to agree you need at least a almost new pad to prevent the heat transfer, and fresh uncooked fluid.
Is there such a thing as a ceramic anti-squel pad backing plate?
Is there such a thing as a ceramic anti-squel pad backing plate?
#43
Somebody is going for a record? : )
Anywho, the backing plate can be titanium (an excellent heat insulator.) Ceramic is too bulky and fragile. The pistons in the calipers can have a ceramic head or coating. Not sure about Porsche from year to year, but there can be a ceramic cap on top of the piston. I have a little brain fade on brake fade.
As for solutions, the way forward is not to throw money at fluid, just dear old ATE blue will suffice and there are concerns about synthetic fluids like Castrol being corrosive to seals in the ABS pump and distributor block. So I recommend looking at slotted floating rotors from the likes of PFC or StopTech or Brembo with their pad.
This is surely the most comprehensively discussed and documented topic for track drivers. You'll find some credible threads in the 997 GT3 forum.
Anywho, the backing plate can be titanium (an excellent heat insulator.) Ceramic is too bulky and fragile. The pistons in the calipers can have a ceramic head or coating. Not sure about Porsche from year to year, but there can be a ceramic cap on top of the piston. I have a little brain fade on brake fade.
As for solutions, the way forward is not to throw money at fluid, just dear old ATE blue will suffice and there are concerns about synthetic fluids like Castrol being corrosive to seals in the ABS pump and distributor block. So I recommend looking at slotted floating rotors from the likes of PFC or StopTech or Brembo with their pad.
This is surely the most comprehensively discussed and documented topic for track drivers. You'll find some credible threads in the 997 GT3 forum.
#45
Instructor
Join Date: Nov 2007
Location: Western USA
Posts: 100
Likes: 0
Received 0 Likes
on
0 Posts
I have " cooked" the fluid in my 2004 tt x50 cab on Thunderhill before, second day on track, and I thought about changing fluid after the first day and did not, second day sure enough 10 laps in brake fluid boiled and no brakes, made it to the pit, 186 on the caliper with a laser temp. I now always change the fluid before and after track days. Hard lesson to learn. Have never had any problems since and also use new pads for track days, with a little break in to seat them correctly, seems the thicker pads also help with heat control. have not lost brakes since. Also make sure the PSM is off, it never really turns off unless you unplug the PSM near the booster, with the switch off it seems to prevent the PSM from clicking the brakes. Never use PSM on the track, at Laguna Seca I did an experiment and turned it on, going into turn one, PSM thought I was out of control and "click click click" straightened me out right past the bridge, really scary at speed, also tried this at an autocross, and missed the slalom as it corrected the car. Having PSM on at the autocross added 5 seconds to my run.