I know I should use the search function for this but what do you guys think? It's not for a track car but a daily driver who enjoys "spirited" driving on occasion. After a half hour of harder than normal driving, I start noticing brake fade so I definetly need help in the "brakes" department. Is it worth it to spend the extra $100 to get the drilled rotors with the Stoptech setup? If I need to turn the rotors, can I take them to my neighborhood repair shop? Which one will last longer? Which one performs better? Right now I am running drilled/slotted front/rear rotors with stock lines and Axxis pads, I noticed when I am driving I hear noise coming from my brakes because as I apply them, the noise gets louder. Kind of like a pulsating noise. Not really a big deal but was wondering if it will get worse if I run Stoptech BBKs? Will the sound get louder with drilled/slotted/both? Any feedback will be much appreciated.

 

It is if you like the looks. Otherwise no.

I've seen it done, but generally speaking, no. Most shops won't want to risk cracking the rotor or breaking the cutting tool off. The guy that turned his slotted rotors used his own lathe and did it very carefully with lots of oil and lots of time. I would expect most places would tell you to just replace them.

Not sure about longevity. I can say that Racingbrake makes some excellent slotted rotors and I've put 22,000 miles on mine thus far with no issues (using Hawk HPS pads). They make some floating ones with seperate hats now too, which look really nice. Somebody else could tell you how the Powerslot rotors work.

Slotted.

Drilled rotors were beneficial in the old days because pad compounds used back then would outgas like crazy while hot. The gases ejected from the pad would form a vapor barrier between the pad and rotor surface, reducing the coefficient of friction vaguely similar to what happens when a car hydroplanes. Modern pads do not outgas nearly as much.

Furthermore, drilling holes through a cast piece of metal weakens its crystalline lattice, making it much more fragile and prone to cracking. Think of how a small crack in a windshield a few inches long will end up working its way across the entire piece of glass with several weeks of wind buffeting against it and you get the general idea. Drilling rotors does the same thing in terms of structurally weakening them. Also, the holes become areas of stress concentration (e.g. stress risers) because they interrupt the stress distrubution across the rotor during braking. So, you end up with a concentration of stress on a spot where the metal is at its weakest. Cracks ahoy.

Finally, the one of the rotor's functions is to act as a heat sink and conduct the heat away from the pad during contact (braking). Drilling material out of the rotor reduces the rotors mass, which reduces its heat capacity. The holes under the pad also reduce the total contact area, reducing the rate of heat transfer. The holes of a drilled rotor also reduce the conduction of heat across the rotor because heat now has to cunduct itself around the holes, which increases the distance it has to travel in order to reach equilibrium. The resultant temperature gradients (hot spots) create areas where the rotor is expanding or contracting against itself, inducing even more stress on its structure, which has been already weakened by the drilling process. All three of these features stand in direct conflict with performance.

Slotted rotors do not have the same structural and thermodynamic weaknesses of drilled rotors. But, they still allow pads to outgas to the atmosphere using the slot channels. The slots have a scrubbing effect on the pad surface, which prevents glazing and removes various debris (to be fair, drilled rotors do this too). Look at a NASCAR rotor sometime and you'll see the slots.

All that being said, you're concerned with spirited street driving. You can get the blingingest mad tyte cheese grater drilled rotors you want and be happy with them because you won't push the envelope enough to hit their points of failure. If you ever feel like going to a track, get some good, heavy, slotted or solid rotors.

That depends more on the pad material used, actually. Ceramic pads are nearly silent and create very little dust. Carbon Kevlar bite a bit better but are a bit dirtier and noisier. The metal compound pads used in BBKs and race pads bite like hell but they tend to dust and squeal a lot. They also take some heating to reach optimum temperature so they aren't good for street use where they'll never get warmed into their ideal temperature range.

 

Wow, very impressed. Thanks for the info, slotted it is.

 

I would get plain rotors. You aren't going to notice any performance benefit using drilled and/or slotted rotors. If you want better brake performance, get better brake pads and DOT4 brake fluid. I'd highly recommend Cobalt GT-Sports (http://cobaltfriction.com), but be warned that they will dust fairly heavily. Axxis Ultimates also work fairly well for the street and won't dust as much.

 

Speaking of solid rotors, Brembo makes some good, heavy, ones that a lot of people here have had good experiences with. Valvoline Synpower is also a good synthetic brake fluid that exceeds the boiling points of both DOT 3 and 4 standards, in addition to being cheap and widely available. I went with slotted rotors because of the other features the Racingbrake slotted rotors have (heavy, large cooling ducts), not primarily because they were slotted. If you still want some of those then contact MrHeelToe. Either will course will serve you well.

I would also strongly consider a set of braided SS lines. You will definitely notice the precision in the pedal with them. To me they make the biggest difference on the street, because you notice their effect every time you tap the pedal rather than only when your brake fluid is ready to boil.

 

HeelToe's Racingbrake rotors: https://acurazine.com/forums/showthread.php?t=37559

 

I've had good success on both street and track with Brembo blanks and Autozone blanks. You can get either for fairly cheap. And I second the recommendation of Valvoline SynPower.

SS lines are good too, but make sure you get one with a clear coating for extra protection. I think most of them have this now.

 

noob question - Which would you rate higher :the Hawk HPS or Hawk Ceramic? I was think about either one of these pads with cryo or non-cryo slotted rotors.