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Discussion Starter · #1 ·
My EuroSport Tuning drilled/slotted rotors have developed cracks in the front two. I installed them in October so this seems very unusual. Anyone had any similar problems?<p>Frank at EuroSport has always been great to work with...I have a call & email in to discuss.<p>Thanks
 

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Re: Ouch...cracked rotors! (854R)

I haven't heard this about the KVR rotors before, but anything is possible with drilled rotors. I would definitely not recommend driving the car with cracked rotors if you can avoid it. I have heard one story about a VW that had a rotor come apart while attempting to brake, due to cracking. Rotors are very hard, but very brittle too. Cracking is not uncommon for a drilled rotor, but usually it happens in racing conditions under extreme heat.<p>Here's a picture of a drilled rotor with major cracks:<br><IMG SRC="http://www.student.nvcc.vccs.edu/home/mtowery/volvo/cracked_rotor.jpg" BORDER="0"><p>I've been using KVR carbon-fibre semi-mettalic pads from EST on the front of my 240 for a couple hundred miles, and so far I'm impressed. When cold, they act just like the old pads I had which came on the car when I bought it, but the big difference comes when the KVR's heat up. I can definitely feel a difference in the braking after a few hard stops. I also had the rotors replaced with grooved ATE PowerDiscs, which may have helped a little, but I think most of the improvement comes from the pad. The down side is that the pads have some nasty black dust, but that was low on my list of priorities when shopping for a performance brake pad.
 

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Re: Ouch...cracked rotors! (towerymt)

Go with stock rotors and high-perf pads, there's a reason no race cars run rotors will drills or slots.
 

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Re: Ouch...cracked rotors! (JZ)

<BLOCKQUOTE>quote:<HR>Go with stock rotors and high-perf pads, there's a reason no race cars run rotors will drills or slots.<HR></BLOCKQUOTE><p>Really? No one uses cross-drilled rotors?<p>Quote from Porsche Cars North American Inc.<br>"On all 911 models, the front and rear discs are cross-drilled to improve braking in the wet."
 

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Re: Ouch...cracked rotors! (JZ)

<BLOCKQUOTE>quote:<HR>Go with stock rotors and high-perf pads, there's a reason no race cars run rotors will drills or slots.<HR></BLOCKQUOTE><p>And if you think those arn't race cars. The GT2 base MSPR is $181,700.00, and it is very much a production race car. <A HREF="http://www3.us.porsche.com/english/usa/home.htm" TARGET="_blank">http://www3.us.porsche.com/english/usa/home.htm</A> It has some of the best breaks ever... on any production car. <IMG SRC="http://www3.us.porsche.com/english/usa/911/gt2/safety/bilder/pccb_foto1.jpg" BORDER="0"> and they look to be cross-drilled also.
 

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Re: Ouch...cracked rotors! (Kaizai)

God, someday I want to own a porsche!!!!! <IMG SRC="http://www.stopstart.freeserve.co.uk/smilie/thumbs.gif" BORDER="0"> <p>Quote from Porsche Cars North American Inc.<br><BLOCKQUOTE>quote:<HR><br>At Porsche, we're committed to developing the very best in performance engineering. An integral part of that concept is brake technology. Which is why the 911 GT2 comes with the most effective braking system ever featured on a production Porsche: the Porsche Ceramic Composite Brake (PCCB) - a powerful new technology designed to cope with even the most extreme conditions on racetrack and road.<p>At the heart of the new technology is a ceramic brake disc made of specially treated carbon fibre silicated in a high-vacuum process at approximately 1,700 ºC. The PCCB disc is cross-drilled and internally vented, and is approximately 50% lighter than conventional alternatives. Since this weight is unsprung, i.e., not supported by the suspension, PCCB automatically improves agility and handling. Another feature of the system is the innovative new composite brake pad, which combines with the ceramic disc to deliver extremely high and constant levels of friction under braking. By replacing conventional metal components with composite pads and discs, temperature is no longer a factor in brake performance. This configuration not only helps minimise braking distances - particularly under heavy use - it also ensures safer deceleration from high speed thanks to improved fade resistance.<p>In an emergency stop, PCCB immediately delivers maximum stopping power to the road. Abrasion is extremely low compared with metal discs, with each PCCB disc offering a service life of approximately 300,000 km. The new composite brake pads also last around twice as long as conventional ones. What's more, the new PCCB pads do not absorb water, making for outstanding performance in the wet. <br><HR></BLOCKQUOTE><br>
 

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Re: Ouch...cracked rotors! (Kaizai)

Porsche uses cross drilled rotors, however, the term cross drilled is misleading. The Porsche rotors are actually cast with the holes, thus helping to prevent the cracking you saw in the picture. <p>Those in the picture are actually ceramic....I think they run about $8K for the set of calipers and rotors...that is if you can actually get your hands on a set.<p>All holed rotors eventually crack (usually under racing conditions)...and are considered to be expendible. Maybe slotted rotors would be better for the street?..<p>Good luck<br>Tom<br>[email protected]<br>87 928S4 AT<br>89 928 GT<br>97 855 R
 

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Re: Ouch...cracked rotors! (midlman)

I agree there is a quality difference <IMG NAME="icon" SRC="http://********************/smile/emsmile.gif" BORDER="0"> my point was that the theory of holes in rotors in not a bad one, it just needs to be implemented in the proper manor to be effective.
 

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Re: Ouch...cracked rotors! (midlman)

By the way, nice car you got there Tom <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0"> <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0">
 

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Re: Ouch...cracked rotors! (JZ)

Interesting photo.<p>I've worked with a brake rotor mfg. before, and they once showed me a test rotor which had been subjected to stress & wear testing.<br>It exhibited similar cracking patterns on the surface. I asked them what causes that type of cracking, and they said that suprisingly, surface cracks are formed by repeated LIGHT application of the brakes, where the surface layers of material heat up and cool down faster than the inner layers of material. (i.e. the thermal expansion cycles vary from surface to interior of the rotor. <p>Almost makes it sound like it's better on a rotor to be heavy on the brakes, rather than light! (Of course, that leads to other problems...)
 

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Re: Ouch...cracked rotors! (Kaizai)

$10,000 option for a set of ceramic rotors (~50% lighter than cast iron) on normal 911 turbo...should be a standard on the gt2 <IMG NAME="icon" SRC="http://********************/smile/emsmile.gif" BORDER="0"> ...<p>as for wet, the film of water that may build up actually has a place to go with the holes...
 

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Discussion Starter · #12 ·
Re: Ouch...cracked rotors! -- Update

OK, here's where things stand. As always, EuroSport is great to work with so we've work out a deal to switch the drilled out with slotted (w/silver cadmium plating). These will still look sharp and hopefully eliminate the cracking problem. Hard to tell what caused it...although the brakes were warmed up, I had kicked the car up to 120mph and back to zero in around 3/4 mile on a country road. It was a hard stop but that's why I was looking for performance rotors...so they could handle it when I needed it. Oh well. <p>Thanks for all the input...here's before and after pics...using EBC Greenstuff pads, by the way.<p> <B>Before:</B> <br> <IMG SRC="http://home.swbell.net/bmhamm/Rotors.jpg" BORDER="0"> <p> <B>After (cracks at 3 & 7 o'clock):</B> <br> <IMG SRC="http://home.swbell.net/bmhamm/IMG_1185.JPG" BORDER="0"> <BR><BR>
[Modified by 854R, 11:39 AM 1-4-2003]
 

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Re: Ouch...cracked rotors! -- Update (854R)

Yeah, like someone said, Porsche brakes are cast with holes. Check the brakes on any race car that aren't ceramic, no holes, no slots. <p>Stock Ferrari brakes = Brembo crossdrilled, street/bling bling only.<br>Stock Ferrari 360 Challenge cars = Brembos, flat rotors.<p>Ask any Club racer if they use crossdrilled/slotted rotors.<p>Throw on stock rotors, or stock cadmium plated rotors, have them cryoed if you're really anal, put your money into brake pads - EBC's are a good choice. <BR><BR>
[Modified by JZ, 1:10 PM 1-6-2003]
 

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Re: Ouch...cracked rotors! (steve s)

<BLOCKQUOTE>quote:<HR>as for wet, the film of water that may build up actually has a place to go with the holes...<HR></BLOCKQUOTE><p>Or perhaps the gas formed when the water hits the hot rotor and boils.
 

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Re: Ouch...cracked rotors! (JZ)

<BLOCKQUOTE>quote:<HR>Go with stock rotors and high-perf pads, there's a reason no race cars run rotors will drills or slots.<HR></BLOCKQUOTE><p>I just flipped through my pictures from the ALMS races in DC this year. I only had a few pictures showing brakes, but one was a Porsche GT car that had slotted rotors. The other pics I had showing rotors were prototype cars, and they used carbon fiber rotors with smooth braking surfaces and ventilation in the form of holes drilled from the outside edge inward.
 

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Re: Ouch...cracked rotors! (JZ)

<IMG SRC="http://www.stickypix.com/data/6046/1091998_astc_s40-brembo_brakes-med.jpg" BORDER="0"> <p>1998 australian super touring car championship...s40. looks like iron rotors with slots to me. if i remembered correctly...the front on the original 1994 btcc 850 estate were cross-drilled...later it was changed to slotted front and drilled rear...guess budget wasn't that high to use composite carbon fiber discs or whatnot <IMG NAME="icon" SRC="http://********************/smile/emsmile.gif" BORDER="0">
 

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Re: Ouch...cracked rotors! (steve s)

Brembo has some cool new rotors coming out on the Lancer Evo 8. Let me look for a picture.
 

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Re: Ouch...cracked rotors! (JZ)

feb 03 motor trend edition...looks like maroon colored 4-pot brembos ... and solid rotors...<p>funny, euro-spec m3 e46 have drilled while us-spec m3 e46 have solid...
 

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Re: Ouch...cracked rotors! (steve s)

S40 ETCC front brakes:<p> <IMG SRC="http://www.student.nvcc.vccs.edu/home/mtowery/volvo/s40bremse.jpg" BORDER="0">
 

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Re: Ouch...cracked rotors! (towerymt)

Are the cross drilled holes countersunk at all? I could see some disk splitting vibration maybe if any kind of edge formed on the those holes at the surface. Looks like it is the outside holes that are prone to split as well, I guess those holes would be always moving faster than the inside holes if that makes any difference, more heat.
 
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