blueovalz Posted June 19, 2001 Share Posted June 19, 2001 For those of you that have been waiting on baited breath, I have finally completed the Supra (12" rotor) brake conversion (replaced the '84 300ZX rotors/'83 280ZX calipers with the '87 Supra rotors and calipers). It envolved a little more work than I at first thought it would (can anybody here relate to that??????), and took an entire weekend to do both sides. The plus side is it cost $65 in salvage parts, new seals, and boots. Additional pictures can be seen at http://albums.photopoint.com/j/AlbumIndex?u=1541023&a=11870007&f=0 My next step is to get the SS braided lines back on the front, but will have to buy them again being the old ones were not long enough. Terry Quote Link to comment Share on other sites More sharing options...
Owen Posted June 19, 2001 Share Posted June 19, 2001 Sorry for the ignorant question but how much of an advantage going to the larger rotor and larger pad? The size increase doesn't look like it's all that much. My application is street so I don't think I could justify it but I'd still like to know how much better this setup is. Also, those look like coilover setups, this is the stock strut right? I love the rear setup, is the ebrake usable? Thanks, Owen Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted June 19, 2001 Share Posted June 19, 2001 Aw man, and I thought 11inches was going to be enough in this club Looks nice, can it be done in 5lug? (lol) Vented? How much work? Will check out pics! Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 19, 2001 Author Share Posted June 19, 2001 Originally, I just slipped these rotors over the front of the Z hub (had to reduce the O.D. of the wheel flange by about 1/8" to do it and then open up the rotor center hole too) and it could have worked very well this way. Plus the original 5 lug pattern is on a 4.5" pattern anyway, which will greatly simplify the rotor swap. Still, some work will be required for the caliper attachment. I only drive the car on the street now, and as such, have not put a full stress test on this system yet. I did ride the brakes real hard around the block a few times, but never felt any fading. I did realize something I had never thought about or knew before, but when I was doing a temp check of the rotors (IR temp) I noticed the inner portion of the rotor was much hotter (300 degrees vs 189 degrees) than the outer portion. Same thing on the rear brakes too. Just an observation. Terry Quote Link to comment Share on other sites More sharing options...
DavyZ Posted June 19, 2001 Share Posted June 19, 2001 Terry, you are the MAN! Good job on the rear discs. Now if only I can duplicate it, then everyone will be able to do it! David Quote Link to comment Share on other sites More sharing options...
Ray Posted June 20, 2001 Share Posted June 20, 2001 How did you attach the Supra caliper ????? Quote Link to comment Share on other sites More sharing options...
blueovalz Posted June 20, 2001 Author Share Posted June 20, 2001 Well, I know some of you ain't going to like this, but after reviewing several ideas on adaptors, I opted instead to lop off the ears that hold the OEM brakes, and then weld a braket I made out of 1/4" thick angle iron in their place. I put 3 additional photos http://albums.photopoint.com/j/AlbumIndex?u=1541023&a=11870007&f=0 of this process at the site showing an abbreviated process. I was leary of cutting up the strut, but it really went very smoothly. I have since done a series of repeated high speed stops and found no inconsistancy from first to the last (5 full acceleration pulls to 85mph/hard stops in a row with no cool down time in between pulls) using normal street semi-metallic pads. This is a great steet set-up, but a full racing set-up would still be preferable if I was to road race again. I'm headed to Disney tomorrow morning for a week, so you guys take care and be safe. Terry Quote Link to comment Share on other sites More sharing options...
Breeze77z Posted July 2, 2001 Share Posted July 2, 2001 I think the temperature difference you're seeing is because you have one piston calipers. The majority of clamping force is being applied to the inside of the rotor, therefore creating more heat. Could also be your wheels letting in air to cool the outer side more then the inner, which ever, shouldn't effect performance too much, but in my opinion, multiple piston calipers would be better than the single kind. But with all the surface area of the 12" rotor and the contact area of the big pads, I bet you see a sizeable increase over stock braking anyway Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 2, 2001 Share Posted July 2, 2001 I have to disagree. If it's a single piston caliper, it's a sliding caliper and both sides of the rotor are going to see the same pressure, or darn close to it if the caliper is binding a bit. If it's binding more than just a bit, well, I can't imagine Terry's car doing that . Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 3, 2001 Author Share Posted July 3, 2001 Thinking about this I have come to this conclusion. The swept area of the rotor is less on the inner radius of the pad as opposed to the outter radius of the pad. With less area, heat is not dissipated as quickly. Which I quess is why bigger rotors run cooler than smaller rotors for the same energy conversion. Yeah Pete, I even installed new bushing kits with the grease and everything so that the floating would be effortless. Terry Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 3, 2001 Share Posted July 3, 2001 Wouldn't larger rotors also run cooler because the speed on the outside of a larger rotor when brakes are applied is slower than a smaller rotor (granted not by much, but a bit)? , Lone Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted July 3, 2001 Share Posted July 3, 2001 The speed for a given distance from the center of the rotor is given by s = R * w where w is the angular velocity of the wheel in radians, R is the radius from the center of the rotor, and s is the linear distance. Therefore the larger the rotor, the higher the relative speed between the rotor and pad. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 3, 2001 Share Posted July 3, 2001 Wouldn't the amount of energy needed to slow the rotor down be less with a larger rotor because the caliper is farther out from the center? Because you can do a comparison by putting a bicycle upside down, spinning the wheel, grabbing the spokes near the inside and trying to slow the wheel down--hard to do. Now spin the wheel, grab the outer edge of the wheel--much easier to stop the wheel. I'm sure this must figure in with a larger rotor. Davy [ July 03, 2001: Message edited by: DavyZ ] Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 3, 2001 Share Posted July 3, 2001 This is the way I see it, based on readign Puhn, Carroll Smith, etc. Please correct me if I don't understand this correctly: If you consider the available friction at the tire/road interface as a limiting braking point, then only so much braking torque is needed. A larger diameter disc with the center of the caliper piston at a larger diameter will need less piston force and pressure to obtain the same friction at the rotor/pad interface for the same rotor/pad friction coefficient. It's a little more detailed than that, but those are the primary effects. But 74_5.0L_Z is right about that linear relationship with rotor radius and speed, and the same holds for needed piston pressure. What this gives you is easier brake modulation and most notably, more brake rotor mass to increase fade resistance. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 4, 2001 Share Posted July 4, 2001 Actually, Pete, that's what I was trying to say in my sort of non-engineer way Thanks for spelling it out in correct terminology. Davy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 4, 2001 Share Posted July 4, 2001 I think I understand that... I know the short square one next to the gas makes it stop, and that long skinny one makes it go... , Lone Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted July 7, 2001 Share Posted July 7, 2001 quote: Originally posted by pparaska: This is the way I see it, based on readign Puhn, Carroll Smith, etc. Please correct me if I don't understand this correctly: A larger diameter disc with the center of the caliper piston at a larger diameter will need less piston force and pressure to obtain the same friction at the rotor/pad interface for the same rotor/pad friction coefficient. What this gives you is easier brake modulation and most notably, more brake rotor mass to increase fade resistance. Yes, I experienced 1000x's greater modulation control along with greatly shortened stopping distances with my upgrade. The modulation was a very welcome and somewhat surprising gain to me. In otherwords...if before I found it hard to modulate my brake effort between 90 and 100% with 100% being lockup, now I find that region within my EASY control. Just like being a lot stronger.....you don't have to lift very heavy objects to benefit......you can control medium weighted objects far greater than someone at their physical limit already. FWIW, inspected my 13" brembo/pbr setup and it shows almost zero wear after some 25,000 km's including my track events. Pads and rotors still appear new with possibly 2-3 thou wear on rotors max as it's barely discernable if at all. Now if only tires would last like that Spacers and studs still look as per new. Quote Link to comment Share on other sites More sharing options...
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