Are the drilled/slotted rotors really worth it?
#31
Hey Jeremy
Let me rephrase....I would go with a blank type of rotor over a cross drilled or slotted. When I say get the cheaper rotor I am talking about getting an OEM replacement blank over the cross/slotted. I'm not saying go with a cheaper material than stock. I would go with Brembo or Powerslot blanks. And last time I checked rotors don't last forever so wouldn't they be considered a wear item? And typically if you warp them bad enough they can't be turned anyway. Cross drilled rotors are known to crack and slotted are known to eat pads. Neither of which are good for a street application.
I used to be a firm believer in cross & slotted rotors but after I started doing HDPE's for several years and talking to people at the events and reading a lot of forums on racing most people tend to agree that they are not worth it. You will still have people saying they are great but the majority of people who have tried them say otherwise.
Read this thread from one of the car clubs I belong to. People are replying with all kind of different cars on this very subject.
I just don't want this guy spending money on something that really isn't going to do anything.
http://chinmotorsports.com/forum/topic.asp?TOPIC_ID=453
I used to be a firm believer in cross & slotted rotors but after I started doing HDPE's for several years and talking to people at the events and reading a lot of forums on racing most people tend to agree that they are not worth it. You will still have people saying they are great but the majority of people who have tried them say otherwise.
Read this thread from one of the car clubs I belong to. People are replying with all kind of different cars on this very subject.
I just don't want this guy spending money on something that really isn't going to do anything.
http://chinmotorsports.com/forum/topic.asp?TOPIC_ID=453
#32
Mitch,
I'm certainly not trying to start up a pissing contest by any means but rather just give out information. Haha, and no I don't think our F-150's would fair to well on track.
I too agree pads wear faster than rotors, well at least typically they do. On a Honda that's another matter. My parents '06 Accord EATS rotors for some reason. At 20k miles they are completely warped. My '06 F-150 however is still with the stock rotors with minimal warping at 60k. I'm running Carquest pads in the front since around 15k I believe.
Could part of the warping problem you had with Hawk pads be from inproper bedding? I've seen plenty of that on my buddies race car I know that much. Just curious....
I'm certainly not trying to start up a pissing contest by any means but rather just give out information. Haha, and no I don't think our F-150's would fair to well on track.
I too agree pads wear faster than rotors, well at least typically they do. On a Honda that's another matter. My parents '06 Accord EATS rotors for some reason. At 20k miles they are completely warped. My '06 F-150 however is still with the stock rotors with minimal warping at 60k. I'm running Carquest pads in the front since around 15k I believe.
Could part of the warping problem you had with Hawk pads be from inproper bedding? I've seen plenty of that on my buddies race car I know that much. Just curious....
#33
Mitch,
I'm certainly not trying to start up a pissing contest by any means but rather just give out information. Haha, and no I don't think our F-150's would fair to well on track.
I too agree pads wear faster than rotors, well at least typically they do. On a Honda that's another matter. My parents '06 Accord EATS rotors for some reason. At 20k miles they are completely warped. My '06 F-150 however is still with the stock rotors with minimal warping at 60k. I'm running Carquest pads in the front since around 15k I believe.
Could part of the warping problem you had with Hawk pads be from inproper bedding? I've seen plenty of that on my buddies race car I know that much. Just curious....
I'm certainly not trying to start up a pissing contest by any means but rather just give out information. Haha, and no I don't think our F-150's would fair to well on track.
I too agree pads wear faster than rotors, well at least typically they do. On a Honda that's another matter. My parents '06 Accord EATS rotors for some reason. At 20k miles they are completely warped. My '06 F-150 however is still with the stock rotors with minimal warping at 60k. I'm running Carquest pads in the front since around 15k I believe.
Could part of the warping problem you had with Hawk pads be from inproper bedding? I've seen plenty of that on my buddies race car I know that much. Just curious....
Last edited by mitch150; 06-25-2008 at 10:29 AM.
#34
As far as pad and rotor wear I've had good luck with the Carquest/stock rotors. I'm still running stock pads in the rear. However, I'd like to have a little more bite from the brakes so next time around if I have the money I'd like to try Powerslot blanks with Hawk pads. Thumper states this improved braking power.
#35
As far as pad and rotor wear I've had good luck with the Carquest/stock rotors. I'm still running stock pads in the rear. However, I'd like to have a little more bite from the brakes so next time around if I have the money I'd like to try Powerslot blanks with Hawk pads. Thumper states this improved braking power.
#36
In the end I got to looking at things, and the stock rotors were in good enough shape to keep. Left them on and installed some Wagner Thermo Quiets and the difference is amazing. Gotta love the warranty as well.
This thread did bring out alot of good info though. I won't be using the drilled and slotted rotors on my trucks any time soon.
This thread did bring out alot of good info though. I won't be using the drilled and slotted rotors on my trucks any time soon.
#37
The immediate difference in braking performance after an upgrade is attributed to the pad, not the rotor. Unless you're competing in the NASCAR truck series, none of us are abusing the brakes on the street in such a manner as to require an avenue for out gassing. additionally, you lose surface area on the rotor for pad contact when you switch to a drilled/slotted rotor. it doesn't take a physics professor to tell you that the more clamping area that a pad has, the better it's going to stop. Slotted/drilled rotors look cool, but different pads with different compounds are going to yield better results than drilled/slotted rotors.
#38
A while back I attended a presentation on brake upgrades put on by Hawk Brakes. They recommend slots but not cross-drilled holes with their pads. They do not like the multi slot rotors though, 3 or 4 is optimum.
When I re-did the brakes on my '96 I went to Performance Friction "Z" compound pads and Powerslot rotors. They made an unbelieveable difference vs. the stock setup. They were also the dirtiest pads I've ever used and the residue didn't want to scrub off my polished wheels (they may be better with clearcoat, I don't know.) They were so bad I replaced them with Hawk HPS pads. They're a whole lot cleaner but they don't work quite as well as the PFC Z pads. The Hawk HP+ compound is comparable to the PFC Z in stopping torque and is a skosh cleaner running.
Whatever pads you use, do not be surprised if you get a clicking sound from your brakes after you install them on slotted rotors. New pads on new rotors will sometimes find the edge of a slot that has a few thousandths of a burr on it. It goes away in less than 100 miles.
When I re-did the brakes on my '96 I went to Performance Friction "Z" compound pads and Powerslot rotors. They made an unbelieveable difference vs. the stock setup. They were also the dirtiest pads I've ever used and the residue didn't want to scrub off my polished wheels (they may be better with clearcoat, I don't know.) They were so bad I replaced them with Hawk HPS pads. They're a whole lot cleaner but they don't work quite as well as the PFC Z pads. The Hawk HP+ compound is comparable to the PFC Z in stopping torque and is a skosh cleaner running.
Whatever pads you use, do not be surprised if you get a clicking sound from your brakes after you install them on slotted rotors. New pads on new rotors will sometimes find the edge of a slot that has a few thousandths of a burr on it. It goes away in less than 100 miles.
#39
#40
the problem with people that swear by their rotor/pad upgrade and those that are on the other side of the fence is that the ones that have done the upgrade haven't a clue if it's the pad or the rotor that made the improvement. no one that i know of or read about has installed the rotors with stock pads, tested them, them swapped back to the oem rotor and new pad. they just slap it all together get better performance out of their brakes and swear up and down that the rotors make a difference.
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
#42
the problem with people that swear by their rotor/pad upgrade and those that are on the other side of the fence is that the ones that have done the upgrade haven't a clue if it's the pad or the rotor that made the improvement. no one that i know of or read about has installed the rotors with stock pads, tested them, them swapped back to the oem rotor and new pad. they just slap it all together get better performance out of their brakes and swear up and down that the rotors make a difference.
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
#43
the problem with people that swear by their rotor/pad upgrade and those that are on the other side of the fence is that the ones that have done the upgrade haven't a clue if it's the pad or the rotor that made the improvement. no one that i know of or read about has installed the rotors with stock pads, tested them, them swapped back to the oem rotor and new pad. they just slap it all together get better performance out of their brakes and swear up and down that the rotors make a difference.
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
in reality, all they've done is decrease the amount of surface area that the pad has available to clamp on to. a rotor, whether oem, slotted or cross drilled is just a flat surface for the pad to clamp on. if the purpose of a drilled/slotted rotor is to provide an avenue for out gassing (and don't even begin to think that on a street truck, you're ever experiencing conditions where outgassing is present) then isn't a more logical explanation that the improved performance is due to superior pad design and compound than a bling lookin' rotor?
Last edited by mitch150; 06-25-2008 at 05:53 PM.
#44
I'll have to back Big Slick and Jeremy's assessments for the most part.
Adding holes, slots, both, dimples, whatever to the rotor won't alter the rotors function as the diameter aspect of the toque equation. It's akin to saying a rubber handled 8" ratchet over a plastic handled 8" ratchet is better. Both provide the same torque given their working values. One is simply easier on your hand. In the case of the drilled or slotted rotor; one or both can can help lower gaseous build up (friction) under the pad thus ensuring a more linear pad contact.
Nevertheless, the real value will always be the pad compound of choice over the rotor surface. A higher friction pad (Cf) will be providing greater torque over the same surface- said rotor. The minimal loss of mass for the drilled or slotted rotor has never proven to make much difference one way or the other. In time most all drilled rotor however do suffer from expansion and contraction heat cycles and develop stress cracks around the holes. That's really all it is.
Most race cars stay away from drilled finishes unless a weight reduction is preferred to longer life. If one is up for changing rotors every couple of events (as some are) then sure; go for it. If longer life and weight issues (think truck) is more important I'd discourage (and do) the use of a drilled surface for use other than a cruiser. That being said adding 13, 14 or 16" rotors to the truck can negate some of the problem by shoring up the total mass of the rotor to begin with. A lower duty cycle for the same resutls = less wear and tear and heat.
Adding holes, slots, both, dimples, whatever to the rotor won't alter the rotors function as the diameter aspect of the toque equation. It's akin to saying a rubber handled 8" ratchet over a plastic handled 8" ratchet is better. Both provide the same torque given their working values. One is simply easier on your hand. In the case of the drilled or slotted rotor; one or both can can help lower gaseous build up (friction) under the pad thus ensuring a more linear pad contact.
Nevertheless, the real value will always be the pad compound of choice over the rotor surface. A higher friction pad (Cf) will be providing greater torque over the same surface- said rotor. The minimal loss of mass for the drilled or slotted rotor has never proven to make much difference one way or the other. In time most all drilled rotor however do suffer from expansion and contraction heat cycles and develop stress cracks around the holes. That's really all it is.
Most race cars stay away from drilled finishes unless a weight reduction is preferred to longer life. If one is up for changing rotors every couple of events (as some are) then sure; go for it. If longer life and weight issues (think truck) is more important I'd discourage (and do) the use of a drilled surface for use other than a cruiser. That being said adding 13, 14 or 16" rotors to the truck can negate some of the problem by shoring up the total mass of the rotor to begin with. A lower duty cycle for the same resutls = less wear and tear and heat.
#45
The rotors I've had on cars & F150's that didn't warp are Brembo blanks and I had one set of Power Slots on my 2001 f150. I've heared powerslots are made from brembo blanks.
I've had a couple of pairs of brembo blanks that were crap, bought from thetirerack dot com. I don't believe all the rotors they ship in brembo BOXES are really brembos. I sent some new ones back that had MEXICO letters in the castings. Wont buy anything from them!
As for pads I've bought quite a few Hawk HPS pads, yes they lay dust on the wheels and don't last over 30,000. Price is about $85 for my 2001 f150.
Next pads are going to be Wagner Thermo quiet for about $40.
Next rotors Brembo for $50 or power slots for $100 (front rotor prices)
I've had a couple of pairs of brembo blanks that were crap, bought from thetirerack dot com. I don't believe all the rotors they ship in brembo BOXES are really brembos. I sent some new ones back that had MEXICO letters in the castings. Wont buy anything from them!
As for pads I've bought quite a few Hawk HPS pads, yes they lay dust on the wheels and don't last over 30,000. Price is about $85 for my 2001 f150.
Next pads are going to be Wagner Thermo quiet for about $40.
Next rotors Brembo for $50 or power slots for $100 (front rotor prices)