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  #1  
Old June 18th 2008, 08:06
2443TT 2443TT is offline
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Has anyone with 944 turbo brakes ever had brake fade?

Hi Guys,

Just wondering if any of you out there running the 4 spot brembo's all round have ever pushed your cars hard enough that youve had the brakes start to fade, and/or boiled the brake fluid.

Personally I dont think is possible unless you have the most crappy brands of pads ever made, unless perhaps your cars has put on some weight and is trying to stop from 200km/h repeatadly around a racing circuit...

I bought new brake pads for my car recently, and the only ones i could source were EBC red stuff ceramics. There wasnt anything more tame available. Thought ive had these before on another car and they felt nice at moderate speeds and got better as they got hotter.

Ive also run bendix ultimax real asbestos pads, supposidly the best pad you can run (though illegal), and they were downright dangerous untill you got them warm. Unpredictable grabbing the rotor left or right... But were amazing when they were warm. Very controllable once up to temperature.

Woo Hoo! Great to see GL up and running again!

Cheers,
Ian
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Old June 18th 2008, 10:45
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Steve C Steve C is offline
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Hi Ian

I was running 4 spots all round on my old 1302/Superbug, a combination of 993 rears on the front with cross drilled 911 rotors, on the rear I ran Boxsters with 944 rotors all with a stock 19mm Beetle master cylinder.

When first got it running I had some green Pagids on the front that came with the callipers, horrible when cold and got slightly better with some heat in them, I ended up using Bendix premium.

I ran the bug at Oran park on a charity drive day and experienced no fade after repeatedly stomping on the brakes at the end on the main straight, in fact the brakes worked so well I kept pulling up too soon for the corner even after leaving my braking ridiculously late.

Steve

PS are you going to share your build on here?
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  #3  
Old June 23rd 2008, 03:06
2443TT 2443TT is offline
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Interesting to know that... I was just curious to know, because some vw guys are running 6 piston brembo's and 330mm rotors. I doubt their pads and discs even get 1/2 way into the pads effective working heat range on a track. Thats something line 2000 braking HP with the 6 piston calipers I think.

Yes I will post up my build on here shortly. I havent made much progress the last few days, but when I start on the rear guards tomorrow i'll post the introduction and do regular updates here.

Cheers,
Ian
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  #4  
Old June 23rd 2008, 03:35
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Steve C Steve C is offline
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Hi Ian

Just think of the weight of some these big brakes, they have to be supported by the suspension and it would be like having 4 gyroscopes when you want to turn plus they take hp to speed up as well. But they sure do look good.

There have been some inspiring buildups on this site, I'm sure that yours will be one that everyone will follow.

Steve
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  #5  
Old June 25th 2008, 19:52
Cam Cam is offline
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Hey Ian, good to see you on here.

I agree with Steve and would stick to what you've got before adding all the extra weight.
I would think that if you wanted to take your braking set-up further, cross-drilled or slotted rotors (I'm betting that yours are already vented, ja?) would be a better investment than replacing your whole set-up.

I used to run a slotted & cross drilled rotor on my go-kart with twin piston caliper and could never justify the extra expense of a vented, slotted & drilled set-up.
This was always because you really don't have to stop much weight or from a very high speed. Plus, I found the same thing as you did in your beetle, on new tracks I was pulling up way too short of a lot of corners (often following other guys into braking zones). I also never experienced fade either, in fact if I stayed on the brakes from speed (even in a straight line) it would just lock up after awhile, or if I left braking too late and had to really STOMP on the thing.
Then I drove a kart with a vented, slotted & drilled set-up and the difference was amazing! The difference I found lay in control under braking, not fade or shortened braking distance. In saying the latter though, I could brake ALOT later and stay on the brakes deep into a corner after a long straight (whereas before I could only brake from speed in a straight line), this allowing me to open up a whole new world of balancing & braking that I hadn't thought of before, or had I explored would of found instant lock-up with my then set-up.
When we swapped to vented rotors (that were slotted & x-drilled too) I was trying to figure out why the difference was so apparent *someone tell me if my assumption is wrong here* and the only thing I could think of was that when under hard braking (despite my rotor being slotted & x-drilled) I was still getting a pressure build up (gasses, circulating air, dirt, grime, crazy brake imps, or the like) when braking from high speed, which was working against the pressure applied from the pistons in the caliper, and when I held on for too long this pressure would build up to the extreme then release, which meant the pressure I was applying at the pedal was far too great, resulting in momentary lock-up. Whereas, with the vented rotor, the pressure from the pads would be vented not only through the slots to the outter edge of the rotor, but through the x-drilling, into the vents & out through the centre of the rotor, resulting in consistent pedal pressure & control under all braking conditions. I think a similar theory can be applied to the lock up when trying to brake going deep into a corner... when forcing load on the inside tire, coupled with the built up back pressure in the rotor, the similar momentary lock-up would occur.

I know that this is a different scenario to a full weight street car on road tires, with suspension, but still worth keeping in mind, since the same parts gave the same result even on a later kart chassis, using different compound tires and change of driver.

Cheers,
Cam
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  #6  
Old December 20th 2009, 00:47
1303GT 1303GT is offline
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I'm new here but thought I would give my .02

I run my 86 944T (951) in some track days and time trials, with some good pads (BHP) and cross drilled zimmerman rotors I have NO fade lapping in 20 Min sessions.
The tracks I run on have long 130MPH+ straights with hard braking at the ends. these brakes are fine for a 300HP 2800 pound car, on the track.

I'm going to be building a 1303GT, ( a german look/Rally style) I plan on using standard 944/924S brakes all around with good pads. IMO this will be more than enough for a 1303 even with a large type 4 engine

John.
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  #7  
Old December 20th 2009, 06:26
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Wally Wally is offline
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I agree: bigger than 944T brakes is not ever 'neccesary', apart from maybe the Divinol track 1303's that ran in real races in germany back then, but those were dedicated track cars.
Maybe even n/a 944 brakes are enough for 98% of all cars, but yours is probably in that 2%
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  #8  
Old June 29th 2010, 13:19
spannermanager spannermanager is offline
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Guys, a little input to bring up an old thread, but in my experience, most 'brake fade' is more down to gas contamination than just the temperature, we had to run stock brakes, no vents, in the beetle cup races, but we could groove them, this dramatically improved the gas removal and hence braking power. previously, the discs needed fetling every run, the gas leaving an almost greasy residue, now i got lazy and did them for every event. most dont even twigg it, why ya doin all that? the DA sander is the tool of choice, cross drilling is not the way for racing, they crack easy, grooves work best....
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