We've had a spell of exceptionally hot weather at the last two race meetings and I'm back to thinking about how I can get more cooling than natural airflow provides.
I'm running BMW E21 vented rotors, Willwood four pot callipers (Minilites I think) and Ferodo DS3000 pads under 14in wheels mounted with 195.60x14 Dunlop Direzza 03G R2 tyres. The pads last three normal race meetings at best and I've had that heat sensitive paint on the rotors that indicate they get really hot so I can't go for a lower temperature rated brake material. Tyres are also only doing about 5 meetings. The rotors are tending to warp/distort and therefore need frequent skimming. I've put this down to difficulties cooling them quickly and evenly.
The photos show that there really doesn't appear to be any easy way to push more air to the rotors, so I would be interested in what others are doing or any ideas please.
photo 4.JPG (92.59 KiB) Viewed 3104 times
photo 3.JPG (115.5 KiB) Viewed 3104 times
comparison of pads after about 100 laps with new ones
Sorry, but skimming the discs is self defeating, the more you skim them the thinner they get, the thinner they get, the quicker they overheat and warp. Bite the bullet and get some new ones!
About the only only other thing you can try, is to duct air from the front of the car as directly as possible onto the discs. But I fancy any gains made that way will be marginal.
Steve
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Thanks Jeroen, that really looks good. 150C reduction is really significant. What diameter are the hoses? Do they connect up to the slots in the spoiler or sit below that?
Agree Steve, I've been having difficulty getting rotors recently as Brembo and others have decided to obsolete them (BMW E21 323i). They aren't something to airfreight in either. However, I've found one supplier left in Australia so I've got a couple of sets coming in. I try to have a very light skim then hopefully I can get a couple of skims before the rotors get to the minimum thickness of 20.4mm (new they are 22mm).
gmsclassics wrote:Thanks Jeroen, that really looks good. 150C reduction is really significant. What diameter are the hoses? Do they connect up to the slots in the spoiler or sit below that?
Agree Steve, I've been having difficulty getting rotors recently as Brembo and others have decided to obsolete them (BMW E21 323i). They aren't something to airfreight in either. However, I've found one supplier left in Australia so I've got a couple of sets coming in. I try to have a very light skim then hopefully I can get a couple of skims before the rotors get to the minimum thickness of 20.4mm (new they are 22mm).
Geoff
I really don't know the dia. These pics are over 10 years old and the mod was done before that. They slot in the existing holes of the front spoiler but these are a bit widened to accept the hose.
There was a big brake overheating problem at that time and even no grease in the front wheelbearings after a race. That was solved by using silkolene rg2. Due to homologation it was std 13 inch rims. At first the hose was just blowing air on the disc face but in real life this does not work at all. The way shown the air is blown in the centre of the disc and blown through the vented part of the disc and escapes at the outside. Forced air is the maximum use of the vented disc principle and the secret of cooler discs.
