lbfdengineer Posted February 26, 2007 Report Share Posted February 26, 2007 I may have missed this, has anybody heard why the Shelby's didn't come with cross drilled disc's. Pre production pictured and litature stated the car was to come with that option. Link to comment Share on other sites More sharing options...
chuckstang Posted February 26, 2007 Report Share Posted February 26, 2007 Drilled brakes suck thats why. They crack over time, just ask a new Vette owner Link to comment Share on other sites More sharing options...
Alloy Dave Posted February 27, 2007 Report Share Posted February 27, 2007 I may have missed this, has anybody heard why the Shelby's didn't come with cross drilled disc's. Pre production pictured and litature stated the car was to come with that option. Don't know for sure, but I can say I prefer non-drilled brakes. By drilling, you lose valuable surface area. The holes are supposed to prevent fade, but they trade off the surface area, reducing stopping power. I have not heard anyone have issues with fade on this car. Dave Link to comment Share on other sites More sharing options...
BADBOY500 Posted February 27, 2007 Report Share Posted February 27, 2007 Don't know for sure, but I can say I prefer non-drilled brakes. By drilling, you lose valuable surface area. The holes are supposed to prevent fade, but they trade off the surface area, reducing stopping power. I have not heard anyone have issues with fade on this car. Dave Good point!!!!!!!!!Mine does stop fast!!!!!!!!O and no fade yet!! Link to comment Share on other sites More sharing options...
RUFDRAFT Posted February 27, 2007 Report Share Posted February 27, 2007 Mine doesn't stop fast enough.... Link to comment Share on other sites More sharing options...
1badsho Posted February 27, 2007 Report Share Posted February 27, 2007 Mine doesn't stop fast enough.... Racing track cars ... crossed drilled rotors help in the cooling of the rotor itself and helps dispate gas that can build up between the rotor and pad and effect braking in itself. On a track car .. cross drilled rotors or grooved rotors help alot do to disapate the intense heat thats builds up on the rotor. On a street car with occasional hard stopping not really needed in my opinion. That plus the metal cools and contracts at different levels on cross drilled rotors .. which is why they are prone to cracking Link to comment Share on other sites More sharing options...
68fastback Posted February 27, 2007 Report Share Posted February 27, 2007 . ...and cross-drilled rotors wear pads considerably quicker -- ok for racing, but not for street. . Link to comment Share on other sites More sharing options...
ratnacage Posted February 27, 2007 Report Share Posted February 27, 2007 . ...and cross-drilled rotors wear pads considerably quicker -- ok for racing, but not for street. . hmm, this has me thinking. I have a few customers interested in some hi-po Mustangs like the Cervini and a sleeper. Current plans call for x-drilled rotors - would slotted rotors be a better choice? I doubt either car will ever see a track (other than the 1/4 mile), although I believe the brakes should be upgraded - brakes are too often ignored; you have to stop too! I was always under the impression that either x-drilled or slotted were equally as good, but having both features should be avoided. ...excellent topic by the way. Link to comment Share on other sites More sharing options...
68fastback Posted February 27, 2007 Report Share Posted February 27, 2007 hmm, this has me thinking. I have a few customers interested in some hi-po Mustangs like the Cervini and a sleeper. Current plans call for x-drilled rotors - would slotted rotors be a better choice? I doubt either car will ever see a track (other than the 1/4 mile), although I believe the brakes should be upgraded - brakes are too often ignored; you have to stop too! I was always under the impression that either x-drilled or slotted were equally as good, but having both features should be avoided. ...excellent topic by the way. I suspect slotted are less prone to cracking over time than x-drilled, but that's just a gut feel, Andre. I notice that most of the hi-end aftermarket Baer and Brebo's are slotted (and with lightweight rotor centers)and the 'racing' ones are slotted and drilled. I think the slotted give most all the outgassing benefits of the X-drilled with less cracking potential, but the drilled ones probably shed heat faster -- also the cause of the thermal-cycle cracking over time, I suspect.. -Dan Link to comment Share on other sites More sharing options...
1badsho Posted February 27, 2007 Report Share Posted February 27, 2007 I suspect slotted are less prone to cracking over time than x-drilled, but that's just a gut feel, Andre. I notice that most of the hi-end aftermarket Baer and Brebo's are slotted (and with lightweight rotor centers)and the 'racing' ones are slotted and drilled. I think the slotted give most all the outgassing benefits of the X-drilled with less cracking potential, but the drilled ones probably shed heat faster -- also the cause of the thermal-cycle cracking over time, I suspect.. -Dan Slotted rotors just allows the rotor to sweep off any gas build up bewteen the pad and rotor. THis helps break efficency which is why tracks cars have. Doesnt aid in cooling though. Again .. track cars see extreme temps on there rotors and pads un like a street car. A street car even being abused wont see these temps dond Link to comment Share on other sites More sharing options...
LSR Posted February 27, 2007 Report Share Posted February 27, 2007 I may have missed this, has anybody heard why the Shelby's didn't come with cross drilled disc's. Pre production pictured and litature stated the car was to come with that option. COST is the reason alot of original options (listed below) were not included on the production car. And most of the pre-production litature says slotted which is production. Ford was trying to keep the MSRP at $39,000 and it came in at $40,000+. 19 inch wheels & tires Cross drilled rotors Hood Lysholm screw-type blower same blower on the Ford GT (which makes for higher top end power) The production GT500's have a R122 Roots-type blower (which makes for more midrange power) Options listed above would have put MSRP on the GT500 around $50,000+ Ford didn't origianlly think the GT500 would be a sucess which played a big part in it's drug out time release. Alot of the power lease holders complained as well as other Mustang owners of paying more than $39,000 for a Mustang. But turns out that the GT500 is one of the most sought after cars in the nation. Ford I think should at least offered cross drilled rotors and 19 inch wheels as an option when ordering a GT500 as well as more exterior colors such as silver and more stripe colors. Link to comment Share on other sites More sharing options...
Alloy Dave Posted February 28, 2007 Report Share Posted February 28, 2007 Hope this is not too far off topic, but I thought I'd add some info on brakes. As many of you know, I was a brake/suspension tech for about 6 years. One of the problems I saw a lot was "warped" (more accurately referred to as "out of parallel" rotors". This manifests itself in different ways depending on the exact nature and which axle it's on. If it's on the rear wheels, it typically results in brake pedal oscillation. In other words, as you hold down on the brake pedal during a normal stop, the pedal will "undulate" up and down slightly. When it happens on the front axle, it typically shows up as steering wheel shimmy under normal braking. There can also be slight "thumping" noises associated with this. The fix is to have the rotors resurfaced, which trues up any "warping" or out of parallel condition. Many people, in water-cooler talk, think this because the mechanic tightened their lug nuts with an air gun. While I'll admit this can be one cause, it's definitely not the only cause, and on cars with "beefy" hubs (like our beloved Mustangs), this is almost never the real cause. Driver behavior can eliminate most of this problem. Let me explain. Let's say you drive down a long hill, and have to come to a fairly hard stop at a red light. You apply the brakes and come to a complete stop. If you visualize the rotor and brake pad, you can see that only about 20% or so of the rotor is "held" by the brake pads at any given time. While the car is moving, during the stop, heat is generated evenly throughout the rotor. However, when you are stopped, the portion of the rotor upon which the pads are clamped are holding that heat in the rotor, essentially heat-soaking that one area. Whereas the "unheld" portion of the rotor is allowed to cool, the "held" portion stays hot, and the metal starts to move differently than the rest of the rotor. Imagine this cycle occurring many times in the normal course of driving, and you can see how a rotor can become "warped". How to preven this? That's easy. When you come to a stop (assuming you are on flat ground), you can either release the brake pedal and sit there...or...if you are one who doesn't think this is safe...inch your car forward 2-3 inches once or twice during the first 30 seconds....to expose different parts of the rotors to the open air and resultant ability to cool. One other cause of rotor warp is that after a long stop, when the rotors are hot, you drive through a puddle of water. If the water splashes on only a portion of the rotor, you can imagine the impact on the rotor. I've not had rotor warp on a single car in the past 20 years by exercising the above driving habits, avoiding puddles when the brakes are hot, and tightening my lug nuts carefully. Now, if you're going to ask about brake "squeal", that's a whole different...and more complex...issue. Dave Link to comment Share on other sites More sharing options...
68fastback Posted February 28, 2007 Report Share Posted February 28, 2007 Dave, great insight... thanks... I've suspected theheat 'spot' heat-soak after a 'hot' stop was a cause but never saw that mentioned anywhere -- good stuff! Just one observation. On the GT500 the tires are about 28" tall so if the pads cover 20% of the rotor you'd have to move forward about 18" or so each time to expose the hot-spot. I have to be more conscious of this in the future, not that I do any really high-speed stops in my present cars, but it's a good habit to get into... thanks for the tips. Dan Link to comment Share on other sites More sharing options...
Alloy Dave Posted February 28, 2007 Report Share Posted February 28, 2007 Dave, great insight... thanks... I've suspected theheat 'spot' heat-soak after a 'hot' stop was a cause but never saw that mentioned anywhere -- good stuff! Just one observation. On the GT500 the tires are about 28" tall so if the pads cover 20% of the rotor you'd have to move forward about 18" or so each time to expose the hot-spot. I have to be more conscious of this in the future, not that I do any really high-speed stops in my present cars, but it's a good habit to get into... thanks for the tips. Dan Thanks Dan, I was just guestimating at the 20%...but your point is well taken....just don't roll into the car in front of you. Link to comment Share on other sites More sharing options...
CoopersShelby Posted February 28, 2007 Report Share Posted February 28, 2007 Why are we talking about this. Break ducts, cross drilled and slotted rotors. If you are running your car hard enough to need any of these items, you better have a full cage installed. How many people with gt500 have ever experienced brake fade, I will say not one. Put your money in good aluminum hats to lighten up the rotating mass and lets move on. Link to comment Share on other sites More sharing options...
68fastback Posted March 1, 2007 Report Share Posted March 1, 2007 . Yesss, sir! <lol> Link to comment Share on other sites More sharing options...
HSURB Posted March 1, 2007 Report Share Posted March 1, 2007 If it's on the rear wheels, it typically results in brake pedal oscillation. In other words, as you hold down on the brake pedal during a normal stop, the pedal will "undulate" up and down slightly. Dave this is really good info. To change the thread again, I once dated a gal that had this symptom you mention above. When you laid on top of her she would undulate up and down slightly. Never did find a way to correct it. HSURB Link to comment Share on other sites More sharing options...
Alloy Dave Posted March 1, 2007 Report Share Posted March 1, 2007 If it's on the rear wheels, it typically results in brake pedal oscillation. In other words, as you hold down on the brake pedal during a normal stop, the pedal will "undulate" up and down slightly. Dave this is really good info. To change the thread again, I once dated a gal that had this symptom you mention above. When you laid on top of her she would undulate up and down slightly. Never did find a way to correct it. HSURB I shoulda known.... Link to comment Share on other sites More sharing options...
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