I'm going to need pads and rotors pretty soon and I'm pretty sure I'm going to upgrade my rotors. My main question is: Is a cross-drilled or slotted rotor going to disipate heat better to prevent my rotors from warping again. I'm almost positive I'm going to go with Brembo but I did notice that on Ebay you can get cross-drilled all the way around for about the same price as the front Brembo pair. I'm looking for all the opinions I can get on these type of rotors.
Stay away from cross drilled on a street car, especially if you're buying them off of Ebay. What are you going to be using the car for? Any racing/HPDE events? Slotted would be a better choice, check out www.frozenrotors.com. Those cryotreated rotors are awesome and their pricing is pretty good. They are a supporter of the club so you get a discount as well IIRC. Also, what kind of car is this going on?
I'll warn you now, I have a set of drilled and slotted rotors. If you brake hard in the winter and get snow in there when they are hot, you run the risk of warping or cracking them. Slotted should be fine, but the cross drilling isn't very happy with quick temperature changes. Cold rain water can do it, snow can do it. Heat them up, hit them with water or snow and *clank* they warp or crack.
I've read that the most common cause of pulsing brakes is uneven buildup of pad material on the rotor, not actual warping. So, I don't think drilled or slotted will be any different as far as that goes. I've heard slotted is better than drilled as far as longevity of the rotor, drilled rotors can crack easier. I have slotted cryo-treated rotors from frozenrotors.com and I've been very happy with them so far. I'd go with name-brand rotors over ebay rotors any day.
It's just my daily driver. The reason I'm looking is because the high speed stopping I occasionally do is killing my rotors. I doubt I will purchase Ebay rotors, I was just wondering if anyone has had experience with them. Just out of curiosity why stay away from cross-drilled?
See post #3 for the answer as to why to stay away from cross drilled. I wouldn't trust cheap Ebay rotors to hold up for very long, especially in the conditions around here. Get a set of the Frozen Slotted rotors and you'll be very happy with both the performance and longevity.
Call frozen rotors and talk to Mark link. Tell him you are from MNSubaru and he will hook you up with the club discount. They also have hawk pads and ate fluid. Cross drilled, as bling as it looks, removes material from the rotor. the more material on the rotor you have, the better is disapates the heat. Stick with the slotted, cryo'd, plated rotors and they will outlast your car. Russ
Drilling will weaken the face of the rotor. Your rotors, like any other metal, will shrink and grow based on their temperature. If you take a piece of metal, and then heat it up to glowing red, then douse it in water, it will possibly deform the metal. Now perforate that metal and do the same thing. I have a set of drilled/slotted/vented Wilwood rotors you can take a peek at sometime if you'd like. They are most definately warped. Like Brian said, drilled rotors aren't a good idea for a daily driven car. They are great for dry conditions, but around here, we don't have dry conditions. Slotted is fine, the groove isn't that deep, and they will scrub the pads. Frozen rotors is probably your best bet. Cryo-treating is a good thing.
It also needs to be said that breaking in your rotors properly is also a big step in keeping them from warping or building up pad material on them. When pads are new they have a little bit of a coating that needs to wear off and if you brake hard and quick instead of gradually applying force you run the risk of warping or buildup, even more so should the ABS need to kick in. Give them about 100-200 miles with some nice long gradual braking to get everything seated. I like going on and off freeway ramps for the stopping distance. I also recommend slotted. Cracks generally form around the edges of rotors. Holes in the rotor increase that "edge space" by a lot. You therefor have a greater likelihood of developing cracks in drilled rotors. And again I'd recommend Diversified Cryo for the rotors. I bet the ones I fit under the 4-pots on my turbo RS are still solid as the day I put them on.
This is just an idea i was kicking around. The main idea behind the driller/slotted rotors is to removes that thin layer of gas which builds up between the pad and the rotor giv you beter contact and thus better breaking. Now i heard somewhere that the pads we have round here today dont generate these gasses which degrade braking. What I heard was that only old pads like pre 90's stuff actually do this making the whole slotted/drilled thing not applicable. I am not sure if there is any truth behind this or not but it does sound kinda reasonable. If you want a rotor that will last you the longest get a solid blank (not drilled/slotted) and have it cryo'ed, and you will have lots of good braking. good blanks will hold up plenty good to daily driving and the cryo treating will prevent warpage and extend life.
Good advice right there. Cross drilled and/or slotting does nothing for heat dispersion. "Blanks" are your best bet for daily use. They're easier on pads. Slotted help "clean" the pad surface and also give the pad more area to bit on to. Some say it makes it a better choice for track situations.
Does anyone know how much the mn subaru discount is?? The reason I ask is that retail on the cryo slotted rotors is 158.71 a piece. I can get the exact same ones wholesale for 111 a piece. Is the MNsubaru discount pretty close to that??
^ call like WRX1 said frozen rotors are pricey compared to other sources but if you get them cryoed they will ast you a lot longer then a normal one will.
Thanks guys. So from all that I've heard it looks like I'm going with cryogenically frozen slotted rotors. I'm still open to opinions though.
I just installed Racing Brake slotted rotors on my car. Added Hawk HPS pads while I was at it. The difference over the old ones is night and day. Ran two AutoXes on them a couple of weeks ago, and everything worked great. Racing Brake heat treats instead of cryo treating. Similar net effect, just achieved from the other end of the thermometer. Their theory is that by heating the blank, any warping due to heat will already have happened, *then* they mill it to shape. Stuart.
I like the hum of slotted rotors under hard baking. Its kinda cool actually. +1 for RB rotors & HPS pads
