Lost brakes on track
01-12-2008, 06:45 PM
#106
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Ed posted
Um no,the wet boiling point is only important when there is moisture in the brake fluid.
The SAE standard for wet boiling point is measured when fluid has 3% water; say 10 year old fluid.....!!
The fluid will certainly not get measurably wet during one track day.
If you do use Ford fluid then change it before a track day; it is cheap enough. Certainly change it every year anyway.
Even if you use much more expensive fluids you should change them annually for best wet boiling point performance & probably also before each track day. So what benefit do you get from the more expensive fluids?
Marton
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Once it gets nice and hot, Wet Boiling Point takes over
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SAE field tests have shown that the average one year old car has 2% moisture in the fluid. A random test of vehicles in the U.S. showed an average water content of 2.6% for vehicles with an average age of 8 years
The fluid will certainly not get measurably wet during one track day.
If you do use Ford fluid then change it before a track day; it is cheap enough. Certainly change it every year anyway.
Even if you use much more expensive fluids you should change them annually for best wet boiling point performance & probably also before each track day. So what benefit do you get from the more expensive fluids?
Marton
01-12-2008, 06:51 PM
#107
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BTW, I use DOT 5.1 which is compatible with Dot 4 & DOT 3 unlike DOT5
I can not find a reasonable price source of Ford HD here but I can buy DOT 5.1 for about 8 bucks per litre.
Marton
I can not find a reasonable price source of Ford HD here but I can buy DOT 5.1 for about 8 bucks per litre.
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boiling point................. DRY / WET Ford Heavy Duty DOT 3...550 / 290 ATE Super Blue Racing....536 / 392 ATE TYP 200...................536 / 392 Motul Racing 600............585 / 421 Castrol SRF....................590 / 518 Performance Friction.......550 / 284 AP 551...........................527 / 302 AP 600...........................590 / 410 DOT 5.1........................518ş /375ş F
01-12-2008, 08:03 PM
#108
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Um no,the wet boiling point is only important when there is moisture in the brake fluid.
The SAE standard for wet boiling point is measured when fluid has 3% water; say 10 year old fluid.....!!
The fluid will certainly not get measurably wet during one track day.
If you do use Ford fluid then change it before a track day; it is cheap enough. Certainly change it every year anyway.
Even if you use much more expensive fluids you should change them annually for best wet boiling point performance & probably also before each track day. So what benefit do you get from the more expensive fluids?
Marton
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SAE field tests have shown that the average one year old car has 2% moisture in the fluid. A random test of vehicles in the U.S. showed an average water content of 2.6% for vehicles with an average age of 8 years
The fluid will certainly not get measurably wet during one track day.
If you do use Ford fluid then change it before a track day; it is cheap enough. Certainly change it every year anyway.
Even if you use much more expensive fluids you should change them annually for best wet boiling point performance & probably also before each track day. So what benefit do you get from the more expensive fluids?
Marton
SAE refers stricly to street, one tough session at the track will bring whatever moisture in the system to the forefront. And, that 2% is a HUGE number.
The title of this thread is "Lost Brakes @ Track", so I can only assume that scenario of the track is the basis of our discussion. You take any car, and drive it to the limit, and I'll put the 928 at the top of the list due to weight, you'll bring all of it's "weak points" to the surface. Hence my original comment about Ford brake fluid not being up to the task, nor is ATE, IMO.
Look at the wet boiling point of Ford vs. Motul, and you'll see what your money gets you. I can attest to the fact first hand over many track days at an extremely technical track that is tough on brakes.
01-12-2008, 10:03 PM
#109
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Ed, I disagree with you.
Water doesn't "come to the surface" as the fluid reaches dry boiling point. It would be awesome if it did, since the boiling point of the water at the 'surface' is way less than the dry (or wet) boiling point of the fluid; it would just flash off to atmosphere and leave you with dry fluid. Hooray!
The moisture in the fluid is gathered over time from the air that's in contact with the exposed surface of the fluid (top of reservoir) . Yes, hot fluid will absorb moisture ever so slightly faster than cold fluid. But the fact that the fluid reaches DBP once does not suddenly make the fluid wet with water and therefore subject to WBP limitations.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
Water doesn't "come to the surface" as the fluid reaches dry boiling point. It would be awesome if it did, since the boiling point of the water at the 'surface' is way less than the dry (or wet) boiling point of the fluid; it would just flash off to atmosphere and leave you with dry fluid. Hooray!
The moisture in the fluid is gathered over time from the air that's in contact with the exposed surface of the fluid (top of reservoir) . Yes, hot fluid will absorb moisture ever so slightly faster than cold fluid. But the fact that the fluid reaches DBP once does not suddenly make the fluid wet with water and therefore subject to WBP limitations.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
01-13-2008, 01:32 AM
#110
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Driving style, as i mentioned, is key here. I can boil brakes on a stock car one way, and have it be absolutely fine the next time out, and drive faster lap times as well. Its all about heat management. Remember, i got a 2:10 at thunderhill with a car with very little HP and brake pads the size of silver dollars. It wasnt comfortable, and they did fade toward the end of the race, but, they did work. double the size with "S" brakes, and 50% more surface area for the S4 brakes (not to mention larger diameters)
just because you reach a boiling point, which by the way is very easy to do with most any brake system, glowing red rotors are a good sign that the temp potential can easily boil the fluid depending on the heat transfer characteristics, doesnt mean you loose stopping power, or get fade . It might take more foot pressure due to the compressible nature of air in the lines.
Laguna is very hard on brakes. I had race weekend with only 2 races, but took my brand new pagid orange pads down 1/2 way.
the wrong pads coupled with driving style probably are the largest factors. fluid choice and quality probably are 3rd in line as far as importance. However, better fluid can (not always) help mask one of the two other factors
ever notice on DE days, that all the cars STINK of brakes???why, they are bedding in in the first couple of sessions. remeber, you have to cook ALL the "glue" out of the pad, or it doesnt work very well, and you end up putting a lot more heat into the rotors for equivilant stopping instances. a new set of racing pads, means i get , if im lucky, one good lap, before the brakes are toast with fade and a soft pedal. (and a bunch of burning brake smell) then, the next session out, usually qual or the race, the brakes are fine and actually get better with every lap.
advice: DE with sport or racing pads. use a racing brake fluid of some type.
Threshold braking is threshold braking. heavy cars dont nessesarily heat brakes any further. greatest HP to weight ratios create the the greatest heat for brakes. the energy to stop a mass of car will go up with the square of speed. speed is the more dominant factor.
sounds a little like the HP /torque discussion, but reversed.
whats the total energy for braking from120mph to 60mph of a 2500lb car in 3 seconds
vs a 100mph to 50mph of a 3500 car in 3seconds? Bet its close to the same.
MK
just because you reach a boiling point, which by the way is very easy to do with most any brake system, glowing red rotors are a good sign that the temp potential can easily boil the fluid depending on the heat transfer characteristics, doesnt mean you loose stopping power, or get fade . It might take more foot pressure due to the compressible nature of air in the lines.
Laguna is very hard on brakes. I had race weekend with only 2 races, but took my brand new pagid orange pads down 1/2 way.
the wrong pads coupled with driving style probably are the largest factors. fluid choice and quality probably are 3rd in line as far as importance. However, better fluid can (not always) help mask one of the two other factors
ever notice on DE days, that all the cars STINK of brakes???why, they are bedding in in the first couple of sessions. remeber, you have to cook ALL the "glue" out of the pad, or it doesnt work very well, and you end up putting a lot more heat into the rotors for equivilant stopping instances. a new set of racing pads, means i get , if im lucky, one good lap, before the brakes are toast with fade and a soft pedal. (and a bunch of burning brake smell) then, the next session out, usually qual or the race, the brakes are fine and actually get better with every lap.
advice: DE with sport or racing pads. use a racing brake fluid of some type.
Threshold braking is threshold braking. heavy cars dont nessesarily heat brakes any further. greatest HP to weight ratios create the the greatest heat for brakes. the energy to stop a mass of car will go up with the square of speed. speed is the more dominant factor.
sounds a little like the HP /torque discussion, but reversed.
whats the total energy for braking from120mph to 60mph of a 2500lb car in 3 seconds
vs a 100mph to 50mph of a 3500 car in 3seconds? Bet its close to the same.
MK
Ed, I disagree with you.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
01-13-2008, 04:44 AM
#111
Rennlist Member
Why? does it matter that this material, no matter what we use, is put on the back of the pad or in the pad "my point of using thicker pads". doesnt the pad itself provide a greater insulation to the heat? Im asking, because i dont know.
If the titanium shield works, and transfers heat at a lower rate, then vs the pad material itself, i might be able to justify it as i change my pads out at 7mm. (about half gone) for the reason of heat insulation. say the pad backing is worth 2mm of pads, as you are, that would be one more track day. I could wait until 5mm to change the pads and then they could pay for themselves after a few brake pad changes.
But, if they really do insulate the pads, maybe its just worth it to use them. However, if the heat dissapation of the pads also is out the rear of the backs, into the calipers, then it could add to the pads not cooling down as fast as they could.
Mk
If the titanium shield works, and transfers heat at a lower rate, then vs the pad material itself, i might be able to justify it as i change my pads out at 7mm. (about half gone) for the reason of heat insulation. say the pad backing is worth 2mm of pads, as you are, that would be one more track day. I could wait until 5mm to change the pads and then they could pay for themselves after a few brake pad changes.
But, if they really do insulate the pads, maybe its just worth it to use them. However, if the heat dissapation of the pads also is out the rear of the backs, into the calipers, then it could add to the pads not cooling down as fast as they could.
Mk
01-13-2008, 08:15 AM
#112
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All brake fluid, the minute it is open and put in your system, had water in it.
Remember it takes on average 1 year to reach 2% Water so in one day you could expect to add about 0.005%
Marton
01-13-2008, 12:05 PM
#113
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Ed, I disagree with you.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
DE's and track days will help you identify the limits of your brakes and fluids. As your day progresses and the air temp rises, and you dive deeper, trail brake later, and generally lap faster, it may seem like the boiling point of the fluid is dropping. It isn't. Your brakes are working harder.
I'd never assume by boiling point is dropping, it is rather that the brake component and fluid temp is higher. Again, this thread started as one related to tracking. I'm a late braker, and was very hard on brakes the first couple of years of driving at the track. Lesser fluids tended to boil quicker, and once you've reached that threshold, you've got mushy pedal that can be cured a bit by some bleeding while at the track.
It has been my experience that fluids with higher boiling points in general, and I think that includes the WBP, are indeed better performers when stressed, and worth the money. That said, I've not felt the need to go to Castrol of Motul 660 as RBF 600 works for me.
Brakes (all of the components) on the track are nothing to scrimp on, and that, as Forrest Gump says, is "all I have to say about that."
01-13-2008, 02:34 PM
#114
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But, if you have street pads, no fluid in the world, except mercury, will not boil on the track. Most folks just deal with the boiling by talking in the paddock after their DE sessions about how mushy their pedal was. Pads are pretty important here a boiling point of 300 vs 500F wont really matter if the rotors are getting near 700F. But, a mushy pedal PLUS some good fade, can be a problem, regardless of the fluid, and is mostly due to the pads.
On the track, you have to drive around such deficiencies, just as you drive around non-race suspension, street tires and extra weight. Brakes are just one of the many factors that let you down in a DE with a stock car.
mk
On the track, you have to drive around such deficiencies, just as you drive around non-race suspension, street tires and extra weight. Brakes are just one of the many factors that let you down in a DE with a stock car.
mk
There's no doubt that track days test all limits. But, again, that is where you get your money's worth on the best brake fluid you can afford.
I'd never assume by boiling point is dropping, it is rather that the brake component and fluid temp is higher. Again, this thread started as one related to tracking. I'm a late braker, and was very hard on brakes the first couple of years of driving at the track. Lesser fluids tended to boil quicker, and once you've reached that threshold, you've got mushy pedal that can be cured a bit by some bleeding while at the track.
It has been my experience that fluids with higher boiling points in general, and I think that includes the WBP, are indeed better performers when stressed, and worth the money. That said, I've not felt the need to go to Castrol of Motul 660 as RBF 600 works for me.
Brakes (all of the components) on the track are nothing to scrimp on, and that, as Forrest Gump says, is "all I have to say about that."
I'd never assume by boiling point is dropping, it is rather that the brake component and fluid temp is higher. Again, this thread started as one related to tracking. I'm a late braker, and was very hard on brakes the first couple of years of driving at the track. Lesser fluids tended to boil quicker, and once you've reached that threshold, you've got mushy pedal that can be cured a bit by some bleeding while at the track.
It has been my experience that fluids with higher boiling points in general, and I think that includes the WBP, are indeed better performers when stressed, and worth the money. That said, I've not felt the need to go to Castrol of Motul 660 as RBF 600 works for me.
Brakes (all of the components) on the track are nothing to scrimp on, and that, as Forrest Gump says, is "all I have to say about that."
01-13-2008, 05:01 PM
#115
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You don't have to drive around deficiencies, a car can be improved upon. I've spent many $ and hours making my car "less-deficient", hence not very stock any more. And while I can still drive to a track weekend, one of my next steps is a trailer as it is becoming less street-friendly.
01-14-2008, 09:00 AM
#116
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Hence my original comment about Ford brake fluid not being up to the task, nor is ATE, IMO
New fluid flushed into the system is not going to have a wet boiling point.
The only time my brakes got a bit soft was at Road America in a few back to back stops, not an issue but was aware of the pedal movement. Running Hawk Blues with S4 calipers. Had I gone with some HT10's I bet it would not have happened.
I've also run Castrol SRF and that fluid was great, but for 99% of the time the ATE worked very well.
Now I run GTS calipers, HT10's and still ATE. I have a few cans of SRF that will be used if I go to high speed tracks as extra insurance.
01-14-2008, 10:46 AM
#117
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I am absolutely **** about fluid change. It gets flushed prior to every event. Let me say unequivocally, and mentioned it in post 103-I don't have trouble with brakes any more, as I've got much larger rotors, calipers, better pads, better fluid and cooling ducts now. I'm also a pretty good driver.
But, when I was taking stock brakes to their limit, as I was getting to be a better driver, Motul was better than ATE, which was better than "X". My statement in reply to Marton's is that there is NO way I'd run "Ford" fluid in my car. Some people can, and if they change regularly, and drive their car to only a certain level, then they'll be fine. Some people also turn brake rotors, that is cheaper than new ones-I won't. Again, the title of the thread includes "track", and I don't think that is a place for lesser brake fluids, or any components for that matter.
I know a lot of people that run ATE too, and are happy, but I also know just as many that felt the RBF600 is superior and spend the extra $7 or 8 or $10 for it. I'm sure there are people that insist on Castrol SRF too, but I've not seen the need to go to that higher expense.
But, when I was taking stock brakes to their limit, as I was getting to be a better driver, Motul was better than ATE, which was better than "X". My statement in reply to Marton's is that there is NO way I'd run "Ford" fluid in my car. Some people can, and if they change regularly, and drive their car to only a certain level, then they'll be fine. Some people also turn brake rotors, that is cheaper than new ones-I won't. Again, the title of the thread includes "track", and I don't think that is a place for lesser brake fluids, or any components for that matter.
I know a lot of people that run ATE too, and are happy, but I also know just as many that felt the RBF600 is superior and spend the extra $7 or 8 or $10 for it. I'm sure there are people that insist on Castrol SRF too, but I've not seen the need to go to that higher expense.
