SPR

It's called driving at a professional level - not improper technique. Anyone that has driven with me will attest to my my ability and my training. You might want to think before you make a groundless assumption like that again, you just embarass yourself.

chris walrod

Driving at the 'professional level' on the streets must imply at the limit every corner, on the edge of dynamic balance. Dont want to preach to the choir, but just be careful doing this on public streets.

SRF fluid requires frequest fluid changes due to its nature of quickly taking on moisture. It is the standard fluid used in many diciplines of racing and it is expensive because of this. Definitely top notch fluid. However, I feel the ATE blue is great and a good balance between OEM Dot 4 and SRF.

I vote for the ATE fluid (gold or blue).

Holger B

I too was wondering the same thing and how old the brake fluid was to do that. I must be "embarassing" myself also. I guess I just drive at an amateur level...

SPR

Yeah, yeah you know what I meant.

I drive at 8/10's usually if by myself (no passenger), but at that level it is greater than what I would say most would approach on the track. Basically the imputation that I MUST be using improper technique was basically an insult without ANY information as most anyone would take it the way it was implied.

Certain sections of malibu are very tight and lower speed, that coupled without the adequate cooling of the brakes = boiling fluid. This is due to the fact that I am going at least 2 or 3x's what normal speed would be through the sections. I was pretty surprised when it occured and backed off accordingly. I then switched out to the super blue and didn't have a problem on the streets, other than sponginess after a run. On the track the lack of cooling reared it's head again, however now with better fluid it ate through the pads ending the day early after the wear sensors kicked in. The pagid S blue pads that I am running are much better in this regard but still wear quasi quickly. That is what you get when you don't want to have premature rotor wear on a daily driver.

I usually don't get upset about the comments on this board unless they are speculatory which this was. I usually give my .02 cents to help others with what I have experienced and people can chose to do what they like with the information. As I have gained much knowledge from this board as well as others I enjoy contributing to help others in the same manner I have in the past.

cosmos

No, that is actaully the opposite of the problem with SRF. It allows NO mositure to be absorbed into the fluid. Its not that it needs to be changed becuase it goes bad so fast, you just need to bleed the system a bit more then other fluids to get the water droplets out of the lines.

SRF is still the best fluid out there. Ford has a truck fluid that they sell which is great as well. Its $6 a bottle, but still not SRF.

Little story behind the Ford fluid is that Ford developed this pick up in the 80's and the engineers did not get togehter on this project. The brake lines actaully touched the exhaust, so instead of re-designing the system, Ford offers a very good, very high boiling point brake fluid for almost free.

mooty

andrew (mcfly) you can tell the dealer to leave your brk fluid alone or else supply them with what you want to be filled.

mjones... your avatar is at laguna seca? when i run stock fluid i will boil it at LS, at TH as well. i run motul 600 now and pedal never goes soft. however, as a matter of routine maintenance, i do bleed the lines after every two track days. that's pretty much bleeding every 2 weeks for me.

with respect to castro's fluid, i HEARD from a very experienced track driver, he leaves the fluid in the system fro 6 months and never bleeds it. replace the whole thing every 6 months (based on his schedule, it's about 30 track days/year)...

hope these data points help.

MJones

One must really work really hard to overcook Porsche brakes, they are one of the finest braking systems on a production car.
Like you've stated the problem has occured on the streets of Malibu as well as on the track, and you are atrbuting it to "lack of cooling".
Improper braking technique will lead to fluid boiling, and root cause is most likely using a constant or increasing brake pedal application, which will build up substantial heat over time vs threshold braking where your initial application is very strong and cooling starts right away. Pad thickness also plays into the equation as they also act as an insulator.

Cooking of brakes is not a common problem with Porsche.

I have used my brakes hard enough to turn my rotors blue and have not suffered the problems which you describe.

Bob Rouleau

SRF is excellent. My personal favorite is Motul 600 Racing fluid. It is DOT 4 compatible and is almost as good as SRF for boiling. It costs one quarter what SRF does and since I change mine frequently it is my preferred brake fluid. The OEM Pentosin is ok on the street but tracking will result in a soft pedal in my experience too.

FixedWing

I hate to say it Cosmos but you're wrong. You are thinking of DOT5 which will not take up water but will instead allow water to collect in the system. Castrol SRF is DOT4 and will take up water like any other DOT4.

But from what I've read, other comments here about it taking up water faster than stock DOT4 are also wrong. in fact, Castrol claims the opposite. Supposedly it will take up water more slowly and also is better able to handle the water held in the fluid. Something about synthetic esters..

My earlier comment about it not making sense if you didn't intend to change the fluid more frequently related to the intended purpose. If boiling is so critical, then change it regularly to take advantage of the dry boiling point!

"Ordinary" racing DOT4 apparently does take up water more quickly than stock fluid (so really should only be used if you are willing to change it at least every few months).

I put SRF in my Turbo when I had PCCB's that were getting incredibly hot. Even so, I never felt that the stock fluid that was initially in the car had boiled. On the other hand, I am sure I used the brakes harder later on. In the Alps once I was able to get the system so hot that there was smoke pouring from the pads. Much of the heat on the PCCB system goes through the callipers. And yet, I still didn't have signs of boiling the SRF. No clue if I would have boiled stock DOT4 fluid.

I personally haven't felt any difference in compressability between stock DOT4 and SRF. But then I never really left it in there long enough to find out. I imagine if you actually boiled the fluid then it would make a difference. I have heard stories of SRF coming out looking black in some race cars which get their brakes extremely hot. I'm sure that would make a difference in feel no matter what the fluid was.

Stephen

cosmos

Fixed and to others, I believe that I have made a mistake.

FixedWing

Better to make a mistake here among friends than on the track!

My best wishes to you and all of us for a happy 2005 !!!

Stephen

Greg Fishman

Cosmos,
Don't listen to chris walrod, he only works on cars that would make any Porsche look like a bag of spare parts and run circles around them. They cost more to run for a weekend that most of our cars cost, so if he says you need to do something I am sure he is wrong and way off. Give us your racing resume....

Greg Fishman

P.S. I just saw your admission, you should be more "diplomatic" with your comments there are people on this board with lots of experience, but sometimes you have to weed through posts to find the gems...

chris walrod

Greg, your making me blush... these cars arent THAT expensive, only $1k per mile, before the driver stuffs-it, that is..

My comment on the SRF (industry standard, BTW) was only based on it providing a soft pedal after 1hr on track, therefore forcing us to bleed before every session. Now for a road car, it may indeed last much, much longer. Sometimes I have trouble keeping things in context..

Happy New Year to all!!

macfly

only $1k per mile
Chris, what cars are these, post some pix and tell us about them, I'm intrigued, sounds like you have an awesome gig!

MJones FWIW I drove the C2's at the PDE Masters at Barber this year, and they get you going at a very fun pace there. I never noticed any kind of fade or pedal sponginess in the cars, but I also hadn't yet felt it in mine so didn't think to ask what fluids they use in theirs.

Just to throw a further brake question out there, at BW in the summer I was running over 1 hour sessions living out my endurance race fantasies in the 100º+ SoCal summer heat. At the end of one of these long sessions the brakes just didn't bite. My pedal was hard but the brakes just didn't bite. My sense was that they felt 'glazed over'. I just made it round the 90º corner onto the start finish straight without incident, and then I tried the brake again, and it was fine, so I kept going, braking much earlier, to see if it would happen again. It did after a I picked up the pace a bit, so I pulled into the pits to look at the brakes. I could see nothing that would suggest any problems, exept that the holes in the discs were jammed solid with brake dust, and it looked as if it might have been packed in tight enough to be actually depositing dust back on the disc. Has anyone ever heard of anything like this, or anything that would explain this odd effect? (This was using Brembo racing fluid, Pagid RS-19's and there was no hint of the going soft, it was just a lack of bite.)