I am trying to upgrade the rear brakes on my S13 to better match the fronts (11% increase in diameter over stock). I found that I can use a Z31 caliper bracket to fit a 291.7mm diameter rear rotor on . HOWEVER I can't find a suitable 4 lug rotor to match it, just a 5 lug (3rd gen alty rear). I do not like the idea of having to drill a rotor, something about not being able to walk into a part store and buy one just rubs me wrong.
FWIW the alty rotor dimensions:
291.7 od
62 height
9 thick
68 hub hole
stock s13
258 od
46.5 height
9 thick
68 hub hole
any suggestions?
m4ff3w
SuperDork
11/3/10 8:23 p.m.
http://grassrootsmotorsports.com/forum/grm/brake-discs-catalog/26273/page1/
lord I love this place.
at least no one yells search 
dang flab it, search results are negative :(
Coleman Racing is good with custom brake parts, but their rotors are only fairly high-end (2-piece), I believe. Might be worth giving them a call. One of the companies I work for makes conversions for 996/7 Turbo brakes on Audi A6/S6s, and we source the rotors from Coleman.
interesting thought. had them mentioned to me once before on a different project. I'm trying to keep things dirt cheap right now. otherwise I would probably swap into a 5 lug setup.
I didn't realize it at the time, but when I upgraded the front brakes I made them larger than the rears. The factory had rears larger than front, which works pretty dam well! Had that sort of setup on my max when I upgraded its rears first. Best mod I did to that car.
