The theory I've heard is that slotted rotors could help with heat by providing a "chamber" for hot gasses to escape.
I can see where slotted rotors could be better in wet environments, but like you, the lesser surface area causes me some pause for hard-braking and a dry environment.

 

If anything, that would allow more friction between the pads and rotors, thus increasing the heat load.

 

So what's the point of having slotted or drilled rotors?

 

I don't have them. Answer your question?

 

Here's my guess on the theories:
Slotted = Possibly better wet condition and all-around venting
Drilled = Weight and possibly better wet condition braking - but I know of no drilled rotors that work well with the tracked S. They all reportedly crack.
Slotted AND Drilled - Great for motorcycles and light weight "styling" on the road for the S.
My slotted Powerslot rotors worked well on my 1.3 mile course where we have two mentionable braking zones. One is hard, late braking precluding a sharp 90 after a fair amount of speed, and the second is rather moderate following a short straight.
I'm guessing that Phoenix International may not be as hard on brakes as some other courses. For example, the Spring Mountain course in Pahrump, NV is a bitch on brakes. 24 turns in 3.5 miles. I do know that after I did that course that my calipers were glazed black!

 

There is something to be said for more surface area equaling more heat transfer (rotor to air). However, drilling or slotting the rotors is not the best way to do this. If you expect the rotors to see enough heat for this to be a concern, the grooves and holes will most likely compromise the structural integrity of the rotor (hence this thread). The best solution for this is solid surfaces with vented rotors (i.e. the stock S2000 front rotors).

I found it interesting that Brembo even warns against using their drilled rotors on the track:

http://www.tirerack.com/brakes/brakes.jsp?...t+Drilled+Rotor

It has you follow the link to slotted rotors...and then warns against even using those for "high-speed track use."

 

good stuff! Thanks!

 

Yes, it's amusing. The drilled rotors talk about being "race-bred", then they say "(but oh yeah, don't use them on the track)". The slotted rotors talk about how much better they are for the track than drilled rotors, but then they also say "(OK for driving schools, but don't use them for racing or high speed tracking)". Most of this is CYA by the Tire Rack. But still, the vast majority of the people who track their S2000s hard enough to really go through a lot of brakes use only OEM-style blank rotors.

 

Power slots cracked, Oem's cracked after much more use with track compounds. Get or stick with OEM.

 

Ok.
So, I'll reverse my usage. Powerslot slotted for the street, and OEMs - or blanks, for the track. (Powerslot slotted may have a slight advantage in wet street situations... and I own a set.)