jing Posted August 16, 2009 Share Posted August 16, 2009 I already understand the different brake upgrades for the ZX, and the stock ZX brakes are good enough to handle a lot of driving, but my question deals with the weight of the caliper. Which of the two (200sx or 280zx calipers) weigh less? Both are similar in performance so I think it would be ideal to go with the one that weighed less? Also which rotors were better the 200sx or 280zx rotors. They are the same diameter but people keep telling me the 200sx are soild while 280zx are vented (even though online parts show both are vented.) I've read this article that the new age slotted and drilled rotors really didnt help much as it increased points on the disc where it was able to fracture, and the only real advantage to discs is to be vented. Is this true? Quote Link to comment Share on other sites More sharing options...
jing Posted August 19, 2009 Author Share Posted August 19, 2009 Does no one know the weights for the calipers or does it really not matter at all? Quote Link to comment Share on other sites More sharing options...
johnc Posted August 19, 2009 Share Posted August 19, 2009 It matters but I doubt anyone has taken the time to weigh the parts. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 19, 2009 Share Posted August 19, 2009 Cross drilled rotors reduce the weight of the rotor. If you need the mass to dissipate the heat that you generate in the brakes, then cross drilling is a bad idea. If you don't then it is a good idea. I ran the solid rotors in front with Toy 4x4 calipers and abused the crap out of them and never generated any cracks at all, perhaps because the solid rotor is a lot thicker than one side of a vented rotor. I used to work on Porsches and it was pretty common to see them cracked, but we didn't replace the rotors until the crack traveled from one hole all the way to another. If Porsche and Ferrari both cross drill their rotors, it's a good bet that the idea probably has some validity to it. All that said, moving to a vented rotor will do A LOT MORE to dissipate the heat you generate than cross drilling. Quote Link to comment Share on other sites More sharing options...
Jon 74 260Z Posted August 19, 2009 Share Posted August 19, 2009 If Porsche and Ferrari both cross drill their rotors Errrrr....., I'm not sure if this is true. A couple of years back, I knew that Porsche was actually making their rotors with the cross-"drilled" holes in them and not actually drilling the holes. (I hate to throw "anecdotal evidence" into the mix but I know a few racers who believe that drilling the rotors severely impacts the metallurgy and causes cracking to occur more easily. ie, the cooling benefits of cross-drilling did not make up for the weakened metallurgy. But since I'm not a metallurgist, I'm easily persuaded by convincing-sounding arguments...) Quote Link to comment Share on other sites More sharing options...
jing Posted August 19, 2009 Author Share Posted August 19, 2009 I've been reading up on a lot of this and it's been shown that crossdrilling rotors don't help dissapate heat but they allow for the vented gasses to pass inbetween the rotor so it does not form a layer and cause brake fade. Drilled rotors just give more points where it can crack. It just looks cool thats about it thats probably why both those companies run it. I know not many people have cracked their rotors but it also reduces the area in which the pad can hold onto it too so braking is less effective while cooling is minimal. The brakes today are of better composition so a lot of time crossdrilling isn't even needed. Lots of racecars today don't even have drilled and slotted rotors. I've read that vented is the best option, more area to clamp, more surface area to cool, reduces rotational mass. Are the rotors for the 200sx and 280zx the same size? I've been trying to find numbers but can't find any. This is for the 82-83 rotors of a 200sx because they are supposibly bolt on in a 280zx Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 19, 2009 Share Posted August 19, 2009 It just looks cool thats about it thats probably why both those companies run it. I know not many people have cracked their rotors but it also reduces the area in which the pad can hold onto it too so braking is less effective while cooling is minimal. The brakes today are of better composition so a lot of time crossdrilling isn't even needed. Lots of racecars today don't even have drilled and slotted rotors. I've read that vented is the best option, more area to clamp, more surface area to cool, reduces rotational mass. I disagree. They do it because it weighs less. They run a larger diameter rotor because it increases braking torque, and then they drill it to make it lighter. Less polar moment of inertia is a good thing. It's like lightening a flywheels or running lighter wheels. All of these things make a big difference. I wish I had a picture of Dennis Hale's rear brakes on his autox 510. It's pretty clear that they're drilling for weight on that set of rotors. As to the holes being drilled or cast as Jon mentioned, I'd be surprised if they were actually drilled on Porsches, since they do so many. I'd guess that they're cast like that. Regardless, they do crack pretty commonly on the Porsches. The ones that I got for the front of the Z were drilled, and those never cracked. Again, extreme usage. Like the time the pad disintegrated and I was trying to stop the car by pushing the pad backing plate directly into the rotor, and eventually the piston punched a hole right through the pad. I threw another set of pads on that rotor and ran it for another 20K miles, many more autoxes and a bunch of track days. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted August 19, 2009 Administrators Share Posted August 19, 2009 They do it because it weighs less. They run a larger diameter rotor because it increases braking torque, and then they drill it to make it lighter. Less polar moment of inertia is a good thing. Exactly. Have a look at any modern sport bike. Same reason. I wish I had a picture of Dennis Hale's rear brakes on his autox 510. It's pretty clear that they're drilling for weight on that set of rotors. About 7 or 8 years ago, I drilled this rear set for a fellow autocrosser with a DAMN fast Rabbit. Last we talked, rotors were still in good shape. It was done for weight and weight alone. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 19, 2009 Share Posted August 19, 2009 Ron, You missed the vertical surface on the hat. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted August 19, 2009 Administrators Share Posted August 19, 2009 His budget could only afford so many holes Quote Link to comment Share on other sites More sharing options...
260DET Posted August 19, 2009 Share Posted August 19, 2009 I already understand the different brake upgrades for the ZX, and the stock ZX brakes are good enough to handle a lot of driving, but my question deals with the weight of the caliper. Which of the two (200sx or 280zx calipers) weigh less? Both are similar in performance so I think it would be ideal to go with the one that weighed less? Also which rotors were better the 200sx or 280zx rotors. They are the same diameter but people keep telling me the 200sx are soild while 280zx are vented (even though online parts show both are vented.) I've read this article that the new age slotted and drilled rotors really didnt help much as it increased points on the disc where it was able to fracture, and the only real advantage to discs is to be vented. Is this true? Irrespective of weight the 200SX are a more modern design caliper, plus they are likely to have a wider and cheaper range of pads available. If you really want light go for aluminium calipers, some Nissans had them. On rotors, slotted is good in that it improves braking performance at the expense of more pad wear. Can make a whirring noise too. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 20, 2009 Share Posted August 20, 2009 That's just what Dennis's rotors look like. Quote Link to comment Share on other sites More sharing options...
jing Posted August 20, 2009 Author Share Posted August 20, 2009 how come all the F1 cars run just solid rotors? Quote Link to comment Share on other sites More sharing options...
jing Posted August 20, 2009 Author Share Posted August 20, 2009 And I understand how saving weight on rotational mass is better for the car but all the fracture points seem to make it not worth it. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted August 20, 2009 Share Posted August 20, 2009 (edited) how come all the F1 cars run just solid rotors? High temp Ceramic and Carbon/Carbon friction technology that means the rotors probably cost as much as your Z does, and thats not counting the costs of the pads and the high temp boil-less brake fluid that costs as much for a millilitre as your Z's walmart bulk DOT-4 stuff costs per gallon. It's a case of Cubic Dollars winning out. Edited August 20, 2009 by kiwi303 spelling Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted August 20, 2009 Administrators Share Posted August 20, 2009 (edited) And I understand how saving weight on rotational mass is better for the car but all the fracture points seem to make it not worth it. Your answer lies in post #4.... If you need the mass to dissipate the heat that you generate in the brakes, then cross drilling is a bad idea. If you don't then it is a good idea. Those "fracture points" become 'no factor' if the rotor is not thermally taxed, as is the case of the VW rotors I posted pictures of. Edited August 20, 2009 by RTz Quote Link to comment Share on other sites More sharing options...
tube80z Posted August 20, 2009 Share Posted August 20, 2009 About 7 or 8 years ago, I drilled this rear set for a fellow autocrosser with a DAMN fast Rabbit. Last we talked, rotors were still in good shape. It was done for weight and weight alone. So you're the responsible party for Marc?! We need to have a talk out behind the shed On my autox car I use the lightweight rotors with gas slots. Not as light as the cross drilled rotors but they last a lot longer. On a friends EP car rotors were lasting one qualifying and race before they broke and he had a lot of ducting. Switching to cryogenic treated rotors solved the issue. He routinely sees 1200 degree temps. Cary Quote Link to comment Share on other sites More sharing options...
Savage42 Posted August 20, 2009 Share Posted August 20, 2009 I'm with Cary on this one! Too many holes are bad! I talked to one of the guys at Wilwood (who is a Z enthusiast!) and he said the main reason they sell drilled rotors is because "they look cool and that's what the consumer wants, so we do it". Performance wise, he recommended going with the GT slotted rotors (with directional venting) for overall performance & longevity. I've got the 12.2" x 1.25" front & 12.2" x .81" rears, so it should slow the car down pretty well. I've heard many good things about cyro-treated parts, which makes total sense in that area! Making a car go fast requires good stuff to slow it down quickly! Quote Link to comment Share on other sites More sharing options...
tube80z Posted August 20, 2009 Share Posted August 20, 2009 how come all the F1 cars run just solid rotors? They are vented, attached is a pic of the Ferrari front brakes from Malaysia this year. The rotor floats on a hat, which floats to the hub on a splined interface. Cary Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted August 20, 2009 Administrators Share Posted August 20, 2009 So you're the responsible party for Marc?! We need to have a talk out behind the shed Quote Link to comment Share on other sites More sharing options...
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