Tracking your 996 ? Replace your brake fluid !

[deschodt]

Don't do what I did, take on good faith that the fluid had been replaced... Besides I should have put Super blue racing fluid in there...

I showed up at Sebring this w/e for a Driver Event with the 996 - been there before many times with my older 911 or my Boxster, never had any issues. The 996 however is about 20 mph faster by the time I get to the same corners, it is also heavier, and if you combine both, it taxes the brakes a lot more than my older cars did! At least that's my theory ! Bottom line, while in the heat of catching up people I started feeling that my heel and toe was getting sloppier (did not immediately occur to me that it was because the brake pedal was sinking), but I was a little suspicious so I braked a little earlier at the last turn (the one that was on TV for the 12h race where the ferrari and the porsche banged each other? a 180 essentially) - earlier meaning @125 MPH instead of 130, heading into the 180! That is when the brake pedal went to the floor! NOT a fun feeling ! Whatever was left by furiously pumping got me from 130 down to 80 or so, after that I was on my own ;-( I made the turn, using an extremely wide line I might add, and sheepishly cut back and took to pit entrance... By which time I could not have stopped the car to save my life, even with pumping !! I had to go park elsewhere in the paddock - you don't want to use the handbrake on hot discs.... 40 minutes later, all was normal!

Super blue brake fluid it is !!!

[wdonovan]

Will take under advisement. Glad you didn't hurt the shiny stuff.

[wwest]

Don't do what I did, take on good faith that the fluid had been replaced... Besides I should have put Super blue racing fluid in there...

I showed up at Sebring this w/e for a Driver Event with the 996 - been there before many times with my older 911 or my Boxster, never had any issues. The 996 however is about 20 mph faster by the time I get to the same corners, it is also heavier, and if you combine both, it taxes the brakes a lot more than my older cars did! At least that's my theory ! Bottom line, while in the heat of catching up people I started feeling that my heel and toe was getting sloppier (did not immediately occur to me that it was because the brake pedal was sinking), but I was a little suspicious so I braked a little earlier at the last turn (the one that was on TV for the 12h race where the ferrari and the porsche banged each other? a 180 essentially) - earlier meaning @125 MPH instead of 130, heading into the 180! That is when the brake pedal went to the floor! NOT a fun feeling ! Whatever was left by furiously pumping got me from 130 down to 80 or so, after that I was on my own ;-( I made the turn, using an extremely wide line I might add, and sheepishly cut back and took to pit entrance... By which time I could not have stopped the car to save my life, even with pumping !! I had to go park elsewhere in the paddock - you don't want to use the handbrake on hot discs.... 40 minutes later, all was normal!

Super blue brake fluid it is !!!

I very seriously doubt, VERY SERIOUSLY DOUBT, that what occurred with you on the track was primarily due to "normal" brake fluid contamination.

There are "high performance" brake pads and/or aftermarket calipers/rotors available that do not transfer/disperse braking heat quickly and evenly and that will sometimes result in BOILING even fully FRESH brake fluid.

It really does sound as if your problem has more to do with a lack of adequate cooling rather than fluid contamination.

Look you system over thoroughly and then decide just how it is possible (NOT!) to get enough contamination into your brake fluid to cause your experience.

Did you remember to turn PSM OFF...?

Inadvertent PSM/TC/LSD braking can be a big contributor to brake heating at track time.

[deschodt]

>I very seriously doubt, VERY SERIOUSLY DOUBT, that what occurred with you on the track was primarily due to "normal" brake fluid contamination.

If you say so.. I have no idea nor any data to refute/agree... All I know is that the fluid was not as recent as I thought it was and I will go to something more heat resistant next time... Of course I will also inspect the system, but the fact that braking returned to normal after cooling off tells me that the fluid was indeed too hot...

You may be 100% right on other causes, I indeed did not turn PSM off... There are a lot of walls at Sebring and it was my first time with 320 hp at that track, I am used to less horses, so I left it on. Could very well have contributed greatly, I could not tell you, I was watching the track and not so much the PSM indicator on the dash !!!

>it really does sound as if your problem has more to do with a lack of adequate cooling rather than fluid contamination.

What do you recommend I do in that case, got some brands of pads that disperse heat better ?

Thanks !

[Izzy]

A couple of thougths come to mind, investing $45 on a Motive power brake fluid system is well worth it. You can change the fluid before track events, I do, cheap insurance for $12.

I have tried Pagid Orange for track events, they worked great on my 99 996. Now I have a 2003, and I did not notice any difference between the 2. I also leave PSM on, never had it on my 99, but the newer car lets me have a lot of fun without the fade.

Does sound like you had dirty fluid to being with, boiled over and got bubbles in it, which made the condition dangerous. Duct cooling is a good idea regardless, can cost a few bucks to install GT3 ducts

[deschodt]

Does sound like you had dirty fluid to being with, boiled over and got bubbles in it, which made the condition dangerous. Duct cooling is a good idea regardless, can cost a few bucks to install GT3 ducts

I have a motive bleeder, believe it or not, but since the dealer has recently serviced the car, well, I assumed.... My bad !!!

Actually, your post is timely, I have a Gt3 bumper on order, I might as well do the ducting at the same time !!! thanks !

[99C2_Riyanto]

I'm the laziest guy when it comes to bleeding brakes. I only do it once a year and that's because PCA tech inspectors force me too :) I do always pay attention to my brake pads and rotors thickness. Sufficient thickness helps dissipating heat too. Are you sure you're okay in those departments?

When my brakes get hotter and hotter, the long pedal travel comes very progressively. I don't just lose it. So, I'm thinking yours must have got heated so quickly to make you lost it all in one corner. There may be other causes to your problem or that brake fluid of yours is really really old. I always use ATE for DE, so I don't know how regular DOT4 brake fluid holds up under track conditions.