Quote:
Originally Posted by feuer
Holes/dimples or slots help air ventilation and expel heat so rotors will run cooler and cool off faster because the hot gas will be allowed to escape.
Shortly > not only for decoration.
Z4 are 0.8lbs lighter each.
http://www.e90post.com/forums/showthread.php?t=627141
(same issue as with GC, ECS need to fix their website  ) |
Fair enough on the weight of the Z4 35is rotors.
Slots and holes might have a small benefit but essentially no modern pads really produce outgassing anymore, so gas is not a concern. As for cooling, the OE rotors are already vented front & rear.
Personally I like slotted rotors and have had them on multiple cars. I like them because the coating keeps the hats from rusting, they look cool in general, and the slots help a bit in the rain. But Brake Drying on our cars minimizes the rain benefit of slots. There aren't many downsides to slotted rotors other than potentially increasing pad wear, but quality of drilled rotors is hit-or-miss. Too many of them end up cracking around the holes.
I'm still planning on slotted rotors for my 335xi when the time comes, but they're really more of a cosmetic upgrade than anything else.
Pretty sure we can agree that in terms of priority of what is going to make the most difference in braking performance, it's pads > fluid > hoses > rotor gimmicks.