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  #31  
Old March 12th 2008, 17:04
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volkdent volkdent is offline
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While it's true that these don't work well for track applications on the cars they come on, on a light car like the bug I suspect there won't be issues with too much thermal breakdown. A lot of guys do take them off after suffering issues due to track usage, maybe that IS why they were available, but they should be overkill for the bug.

What pads are you going to end up using? Are there specific ceramic pads that need to be used?

Jason
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  #32  
Old March 12th 2008, 17:24
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Originally Posted by volkdent View Post
While it's true that these don't work well for track applications on the cars they come on, on a light car like the bug I suspect there won't be issues with too much thermal breakdown.
Exactly! Not everybody sees the whole picture or so it seems.
Quote:
A lot of guys do take them off after suffering issues due to track usage, maybe that IS why they were available,
True again; their loss, my opportunity as I saw it
Quote:
but they should be overkill for the bug.
How can less unsprung weight be ever 'overkill'?
As stated earlier, I just used the (smaller) rear ones on the front, so the brake action in that respect is not likely to be overkill either...
Quote:
What pads are you going to end up using? Are there specific ceramic pads that need to be used?

Jason
No, as far as I could trace down, there are certain Pagid types that they come with as stock, but those are used on steel disks too. A softer than stock pad for the PCCB type 1 is usually recommended to enhance disk life for the type1 PCCB disks. There is a special tad bit softer race Pagid pad for this as well, but they are very expensive too. That leaves your very spot-on remark about the (huge) difference in weight, so I'll try another OEM (but very affordable) stock pad for these to see how it goes. I can always buy the expensive pads later if these don't work well for whatever reason. At least the disks are now good for another 300.000 km
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  #33  
Old March 12th 2008, 20:11
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"{How can less unsprung weight be ever 'overkill'?
As stated earlier, I just used the (smaller) rear ones on the front, so the brake action in that respect is not likely to be overkill either...}"

Ooops, I mean too much brake, not too light. I think the light is AWESOME, especially on a light car like ours, the weight reduction alone is reason to do the conversion you are doing. It's more brake than you'll ever use, but less weight is ALWAYS good thing. What I thought was overkill for both reasons was that guy that was putting Cayenne brakes on his chassis, those suckers are heavy AND too much brake!

I do have to say though, the thickness of the rotors should be close to minimum spec that Porsche quotes, if they are too thin they actually could shatter. I saw footage of a Corvette C6R explosion of the rotor, it wasn't pretty...

Jason
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  #34  
Old March 13th 2008, 11:48
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Wally,
Any idea when you will be in a position to try them out? Looking forward to the verdict!
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  #35  
Old March 13th 2008, 14:51
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Wally,
Any idea when you will be in a position to try them out? Looking forward to the verdict!
Rich
Well, the car is still with his *ss up in the air awaiting the further modified tranny and an engine.
I have bled the brakes and the disks and calipers are very nice aligned right now (which was a big question mark at first too!).
There is a 1/4 mile track meeting on May 18th over here, so I hope to have tried and tested the brakes by then. Maybe just with a stock 2 liter engine (the riechert one) first as the turbo engine may take a tad bit longer to be completed.

I actually think these rear brakes will be less brake force than the 304x32 disks and M030/928S front calipers I had before. These yellow rear ones up front really have smallish cups (30/28 iirc), even compared to the 993 rear calipers (34/30) I have in the...rear
Hence the installation of the Tilton brake bias valve I have installed now with the new set-up. Depending on the bias, I may even use smaller rears (964 C2's?) afterwards.
I did think this through just a little bit you know
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  #36  
Old March 13th 2008, 15:18
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lookin great nate i cant wait to see the verdict

Thanks for the info on using the 2 pot 964's btw. ive just finished my rear conversion and only needed 1,5mm spacers for the caliper in the end! my mate made them from aluminium too
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  #37  
Old May 7th 2008, 17:53
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Recently I was finally able to drive a few hundreds meters round the block with the 'new' engine and also tried out the ceramic brakes.
Unfortunately, one disk probably had been flaked too much and/or turned down too little. Anyways, the new pads were eaten alive by that disk. I have never seen so much brake dust in all my life: even the fender was covered with brake pad dust!
Within a few blocks, the pad of one side of one disk was totally gone. What looked like a smooth disk was now a rough landscape again. Too bad, as the other disk was perfectly fine and so were the pads. Even though I proved you can machine these disks, too much flaking will not be possible to remedy totally. For this one bad disk even I feel more machining is not safe anymore, so the project will end here
Well, if you never try s/th new, you will always get the old same results.

Anyways, to be able to go to meetings this summer, I looked and found a steel replacements: Its 330x28 and comes from the rear of a 996 turbo/ C4S or 997S or turbo.
The ones I found are from a very recent 2007 997S and basically only need the caliper to be adjusted for heigth, which is very doable.
New pads (Texstar) arrived today, so the bug will be able run again this weekend

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  #38  
Old May 7th 2008, 18:10
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It's too bad about the ceramics. They looked amazing. I've read that what you're doing now is really common among PCCB owners anyway though (swapping out for iron rotors).
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  #39  
Old May 8th 2008, 03:29
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Hi Wally

To bad that it didn't work. I wonder if it would have made a difference with which direction that they were turned when machining, clockwise or anti clockwise? The fibres may have been raised up, like patting your cats fur backwards.

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  #40  
Old May 8th 2008, 04:50
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Quote:
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Hi Wally

To bad that it didn't work. I wonder if it would have made a difference with which direction that they were turned when machining, clockwise or anti clockwise? The fibres may have been raised up, like patting your cats fur backwards.

Steve
I see what you mean, but as I see it this stuff is not like a GRP-made fender where actual fibers are still present when you scratch or sand them. I suppose the baking process took care of that. Lets just say its weird stuff.

These recent week, I have been trying to look for a direct replacement and found many posts concerning problems with pccb brakes on Rennlist and such, like vwdevotee mentions above.
This really lets one to believe the PCCB generation I disks have indeed a serious problem in longlivety. There have been reports of disks failing as soon as 15K miles and when they do, they eat up the pads - even the 'right' original porsche pads - in very, very short time (I know now how that looks). That almost gave Porsche a (legal) claim from safety point of view...

This week, at the local porsche dismantler, he had two cars there with the PCCB (Gen.I) on them. One was his own street car (650 hp GT2 Cup) and his racer. His admitted that the first two laps on the track, it was tricky because the brakes didn't bite that much initially as he was used with the steels and indeed needed to warm-up before they performed well. Then they performed extremely well. The track car had also the beginnings of worn disks, as did the 'street' car which saw track days as well. A spare set of PCCB's gen I from a wrecked car he also had looked immaculate however. Even the yellow calipers had no discolorization, suggeting no overheating had taken place.
All this info I got there leads me to believe that excessive (over)heating is what kills these disks rapidly. That is probably why porsche made the
the generation II disks, which have 2000 fibers instead of 400 per unit (so I have read) and are 380mm instead of 350mm diameter for even better cooling.
Even with these, the Manthey racing team supposedly uses one set of the Gen.II disks at every race. Well, at least they now sustain at least the whole race...
So much about the ceramics
The 'pancake' disks the I have now om still look huge IRL; I just have to look elsewhere for saving some unsprung weight I guess. The really light pccb calipers I can maintain do help a bit fortunately. Total weight of rotor and caliper as compared to the former set-up is still 1,5kg less ;-)

Last edited by Wally; May 8th 2008 at 04:53.
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  #41  
Old May 8th 2008, 14:37
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Sandeep Sandeep is offline
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Thanks for the update Wally.

Sorry to hear that it did not work out (50%) but you're only 50% away from having a working pair

Glad to hear you have a working solution now.

Sandeep
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