Phantom Posted September 11, 2015 Share Posted September 11, 2015 (edited) OOPS - should be WILWOOD brake conversions Back in 2004 I did a Wilwood front brake upgrade on my car using JSK Innovations components. The kit used Wilwood Superlight calipers and 32 vane Ultralite rotors. It was in conjunction with a Modern Motorsports 240SX/300ZX disc brake conversion on the rear. It was recommended that I go with hard pads in the front and soft in the rear "to better balance the braking". After 27,000 miles the front rotors were badly worn - evenly worn - but needing replacement. The pads were about 60% gone. I contacted Wilwood and talked with one of their engineers. We went through what I had on the car, how it performed, etc., and he was totally on board when I said I was not happy with the durability of the rotors. After more discussion and additional research on his part he agreed that I could substitute the Spec 37 GT 48 vane slotted rotor for my Ultralites. That they were dimensionally the same but the Spec 37's are built to higher tolerances and can handle a lot more heat. He also recommended using the Wilwood BP-20 pads for everyday driving and occasional racing but, if I got into some more serious competitions, I needed to install BP-40 pads for those events. When I installed the original Ultralights they also had runout with resulting vibration when braking. I took them to Nissan and had them turned on the car and they worked fine after that, even though it was only for 27k miles. They also squealed horribly. The first thing I noticed about the Spec 37's was they have none of that vibration - and so far they don't squeal. I went to extreme measures to ensure all the mating surfaces were clean before assembly so a bit of debris between mating surfaces wouldn't cause me headaches. Evidently that along with the tighter manufacturing tolerances from Wilwood did the job. I also did a proper "bedding in" of the brakes right after their installation. Bottom line - if you have any of the front disc brake conversions out there that use the Wilwood Ultralite rotors you can replace them with the Spec 37's with no modifications. The Spec 37's are heavier so they increase unsprung weight but they should be way more durable - especially when run with the right pads. Edited September 11, 2015 by Phantom Quote Link to comment Share on other sites More sharing options...
jmhtx Posted September 11, 2015 Share Posted September 11, 2015 Or Wilwood. Quote Link to comment Share on other sites More sharing options...
Phantom Posted September 11, 2015 Author Share Posted September 11, 2015 Or Wilwood. I stand corrected. See any other errors? Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted September 20, 2015 Share Posted September 20, 2015 Have to ask. Did you remove the pressure valve in the rear of the car? It sounds like if you still have it on the car. I had to remove it to get enough pressure to the rear brakes to work. I am running the 300zx brakes on the front and the 280zx brakes on the back. If you have, the things they ask you to do should have worked. I also have racing brake lines on the front and Nissan stock brake lines (rubber) on the rear. Some people have added an adjustable brake reg. devices on it. Because some times, without it you can lock the rears up faster then the fronts. If you have already done this, just disregard this message. Quote Link to comment Share on other sites More sharing options...
Phantom Posted September 20, 2015 Author Share Posted September 20, 2015 Not sure what you mean about a pressure valve in the back of the car. My 280 came with a stock pressure proportion inch valve on the firewall. I have an adjustable pro portioning valve to allow setting the correct pressure to the rear brakes to keep them from locking up. I also have SS brake lines on all 4 corners. I think the 12.2" rotors with the 4 piston calipers are just a lot stronger than the 240SX/300ZX setup. Quote Link to comment Share on other sites More sharing options...
jt1 Posted September 20, 2015 Share Posted September 20, 2015 Phantom, my experience mirrors yours. The GT48 series are a lot better rotor than the lower priced versions, well worth the money especially if you track the car. jt Quote Link to comment Share on other sites More sharing options...
Phantom Posted September 20, 2015 Author Share Posted September 20, 2015 The Ultralight 32 vanes I think would have lasted longer than 27k miles if I would have gone with a softer pad like the Wilwood BP-20s. In that 27k there were only 2 auto rose days and one hill climb. I used to be a bit rough on brakes but "I'm better now". For street only driving with the right pads the Ultralight rotors probably would have lasted closer to 50k miles. Then, again, other than cost, the ultralights are supposed to reduce unsparing weight for racing applications. For a track only car they would probably only last 7-10k miles. But, that's quite a few miles on a track. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted September 22, 2015 Share Posted September 22, 2015 I started with the ultra light rotors for track car to try to keep weight down. They lasted OK but one eventually cracked. Luckily on the cool down lap of last session on Sunday. I replaced with the heavier version and immediately noticed more consistent stopping performance due to the extra heat capacity. Have not cracked one of those yet either and have run the same pair for the last several years. Quote Link to comment Share on other sites More sharing options...
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