991.2 Additional Brake Cooling
Discussion
I have a 991.2 GTS, which I track from time to time. The car is stock apart from running GiroDiscs and Pagid RSL pads for track days. I'm limited to a 350mm disc and on the whole the set up works fine. However, getting some additional cooling into the discs and callipers would be good.
Does anybody have a suggestion on how this could be achieved? Maybe air ducks from a GT3 or similar could work, or an aftermarket product?
And, is it worth changing to SRF brake fluid and / or braided brake lines? Or will this just encourage more brake pressure and in turn more heat?
Thanks.
Does anybody have a suggestion on how this could be achieved? Maybe air ducks from a GT3 or similar could work, or an aftermarket product?
And, is it worth changing to SRF brake fluid and / or braided brake lines? Or will this just encourage more brake pressure and in turn more heat?
Thanks.
SRF works well against heat but needs fairly regular changing.
The Gt3 air ducts that clip onto the bottom arms are a good shout, they used to be only a few quid each but the prices may vary a lot between models. If they are looking like daft money ask for a price for the ones on a Gt3 Cup or Gt4CS race car as they may be the cheap ones.
The Gt3 air ducts that clip onto the bottom arms are a good shout, they used to be only a few quid each but the prices may vary a lot between models. If they are looking like daft money ask for a price for the ones on a Gt3 Cup or Gt4CS race car as they may be the cheap ones.
Steve H said:
SRF works well against heat but needs fairly regular changing.
The Gt3 air ducts that clip onto the bottom arms are a good shout, they used to be only a few quid each but the prices may vary a lot between models. If they are looking like daft money ask for a price for the ones on a Gt3 Cup or Gt4CS race car as they may be the cheap ones.
Thanks Steve. Is there an alternative performance brake fluid to SRF that doesn’t need changing any more often than the normal two years? I noted on another thread that Manthey use Endless brake fluid? The Gt3 air ducts that clip onto the bottom arms are a good shout, they used to be only a few quid each but the prices may vary a lot between models. If they are looking like daft money ask for a price for the ones on a Gt3 Cup or Gt4CS race car as they may be the cheap ones.
I think it's all hygroscopic and that's why it needs changing ... but you will be going through brake pad material faster than the change time for fluid ?
Braided hoses help a pedal which becomes soft due to flex in the hose walls once the fluid is hot ... is the pedal becoming soft ?
If the pedal goes to the floor then water in the brake fluid has boiled and you are trying to compress steam ... etc.
Braided hoses help a pedal which becomes soft due to flex in the hose walls once the fluid is hot ... is the pedal becoming soft ?
If the pedal goes to the floor then water in the brake fluid has boiled and you are trying to compress steam ... etc.
ChrisW. said:
I think it's all hygroscopic and that's why it needs changing ... but you will be going through brake pad material faster than the change time for fluid ?
Braided hoses help a pedal which becomes soft due to flex in the hose walls once the fluid is hot ... is the pedal becoming soft ?
If the pedal goes to the floor then water in the brake fluid has boiled and you are trying to compress steam ... etc.
Occasionally the pedal goes a little soft on a hot day with lots of track time. But not to the floor by any means. The concern is, by adding brake fluid that can operate at a higher temperature. aided by adding braided hoses, and allowing more pedal pressure, am I likly to be introducing more heat to the discs and pads? If so then more cooling is required ahead of fluid and hoses?Braided hoses help a pedal which becomes soft due to flex in the hose walls once the fluid is hot ... is the pedal becoming soft ?
If the pedal goes to the floor then water in the brake fluid has boiled and you are trying to compress steam ... etc.
Good quality brake fluid such as SRF or Endless (currently favoured) will avoid any boiling issues and braided hoses will firm up the pedal, but the same amount of heat is being generated by the brakes.
That's why cooling down laps are so important ... and of course not using the handbrake once back in the paddock. I have seen brakes get so hot that cars have come in with pads on fire ... and have gone back on circuit just to cool and extinguish them ... not a good look !
Improving cooling is the answer, or braking a little differently ... hard and late and not riding the brakes, ... hence you see Porsche paying a lot of attention to air ducting into the brake area.
Steels that get too hot can warp and then cause horrid judder, PCCB's that get too hot just evaporate and oxidise their life away. The PCCB's are much worse than the long fibre carbon brakes because they do not conduct heat away very effectively .... hence pads can last a comparatively short time due to heat damage. The attached is interesting ... Ferrari in their 296 Challenge cars are now using the very latest CCM-R Plus technology ... Surface Transforms ?
With the better conductivity, heat is conducted very effectively into the hub carrier and wheel, giving a much larger and more effective surface area for cooling to the air flow rather than into the brake pad, caliper and fluid. Hence where I was getting three trackdays to a set of brake pads with PCCB's on my GT4, when I changed to ST discs I managed up to ten trackdays per set of pads. In addition after around 100 trackdays the ST's were refurbished at a cost of £2500 and were like new ... I was told at this rate they would refurbish another four or five times. Quite a saving ...
That's why cooling down laps are so important ... and of course not using the handbrake once back in the paddock. I have seen brakes get so hot that cars have come in with pads on fire ... and have gone back on circuit just to cool and extinguish them ... not a good look !
Improving cooling is the answer, or braking a little differently ... hard and late and not riding the brakes, ... hence you see Porsche paying a lot of attention to air ducting into the brake area.
Steels that get too hot can warp and then cause horrid judder, PCCB's that get too hot just evaporate and oxidise their life away. The PCCB's are much worse than the long fibre carbon brakes because they do not conduct heat away very effectively .... hence pads can last a comparatively short time due to heat damage. The attached is interesting ... Ferrari in their 296 Challenge cars are now using the very latest CCM-R Plus technology ... Surface Transforms ?
With the better conductivity, heat is conducted very effectively into the hub carrier and wheel, giving a much larger and more effective surface area for cooling to the air flow rather than into the brake pad, caliper and fluid. Hence where I was getting three trackdays to a set of brake pads with PCCB's on my GT4, when I changed to ST discs I managed up to ten trackdays per set of pads. In addition after around 100 trackdays the ST's were refurbished at a cost of £2500 and were like new ... I was told at this rate they would refurbish another four or five times. Quite a saving ...
Edited by ChrisW. on Sunday 16th February 16:26
Braided hoses and Endless brake fluid fitted, time will tell if the the upgrade is worth it. I suspect it's a very small increment. But can't hurt to have them in place.
As you probably know, OPC's are now using the Endless fluid on their Manthey upgrades. Service manger also tells me that the expected life span usability of Endless fluid is longer than the standard fluid.
As you probably know, OPC's are now using the Endless fluid on their Manthey upgrades. Service manger also tells me that the expected life span usability of Endless fluid is longer than the standard fluid.
Gassing Station | 911/Carrera GT | Top of Page | What's New | My Stuff