Blank rotors
#21
Wagner blanks from Advance auto parts.....very sweet and extra thick....will tuck out wheel slightly. MADE IN USA....fair priced but not rockbottom wear-ever price.
So spend the few extra bucks.
So spend the few extra bucks.
#22
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I have brakemotive's slotted and drilled rotors and they are very quiet. You can feel the slots but they are no where near "pulsing" in the way that warped rotors would ....it's more of a soft discrete rubbing sound. Still miles better than the screeching school bus sound my blanks caused.
Plus, there is little that can't be said for being able to have stopping power above 100mph. Blank rotors _SUCK_ for that.... at least mine did.
Plus, there is little that can't be said for being able to have stopping power above 100mph. Blank rotors _SUCK_ for that.... at least mine did.
#23
I have brakemotive's slotted and drilled rotors and they are very quiet. You can feel the slots but they are no where near "pulsing" in the way that warped rotors would ....it's more of a soft discrete rubbing sound. Still miles better than the screeching school bus sound my blanks caused.
Plus, there is little that can't be said for being able to have stopping power above 100mph. Blank rotors _SUCK_ for that.... at least mine did.
Plus, there is little that can't be said for being able to have stopping power above 100mph. Blank rotors _SUCK_ for that.... at least mine did.
Holes and slots and such are purely for cooling.....and my guess is are necessary only under certain conditions.....likely not seen on the street. It is gimmick really. Stick w/ blanks.
#24
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they're for gas venting too. which is what happens to blanks. The pads gas up and then you have a layer of gas under the pads instead of rotor. Try braking at 130mph with blanks with even decent pads and then try in someone's car with slotted rotors (drilled helps with the cooling and de-gassing too but the slots are really where the works is done).
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
#26
they're for gas venting too. which is what happens to blanks. The pads gas up and then you have a layer of gas under the pads instead of rotor. Try braking at 130mph with blanks with even decent pads and then try in someone's car with slotted rotors (drilled helps with the cooling and de-gassing too but the slots are really where the works is done).
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
You've noticed this often? And feel the slot drives this gas out?
The gas is a derivative of what? the pads burning up as they hit the rotors?
#27
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they're for gas venting too. which is what happens to blanks. The pads gas up and then you have a layer of gas under the pads instead of rotor. Try braking at 130mph with blanks with even decent pads and then try in someone's car with slotted rotors (drilled helps with the cooling and de-gassing too but the slots are really where the works is done).
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
Gas doesn't build up between rotors and modern brake pads. That happened when brake pads were made with asbestos :rofl:
Slotting helps slightly with cooling and shedding of debris but that's about it. Pads and Calipers change stopping distance much more so than the type of rotor you run.
#30
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they're for gas venting too. which is what happens to blanks. The pads gas up and then you have a layer of gas under the pads instead of rotor. Try braking at 130mph with blanks with even decent pads and then try in someone's car with slotted rotors (drilled helps with the cooling and de-gassing too but the slots are really where the works is done).
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
Less material = builds up heat faster. Heat is what causes brake fade under hard braking. Also, less material on the surface = less surface area, which creates a smaller swept area and decreases braking force.
As mentioned, the changes you saw were a change in pads, and probably nothing more. To find some more information, search for some of the huge threads that have blown up on here, there's a ton of good information from the people that really know how this stuff works. Also, reading the brake writeups on TireRack or most manufacturers websites is a pretty good idea as well.
#31
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they're for gas venting too. which is what happens to blanks. The pads gas up and then you have a layer of gas under the pads instead of rotor. Try braking at 130mph with blanks with even decent pads and then try in someone's car with slotted rotors (drilled helps with the cooling and de-gassing too but the slots are really where the works is done).
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
it's like night and day
I guess if you've never gone fast enough to be really concerned that you wont be able to stop in time for an intersection then you're right, it's not something you probably need. I'm far from a crazy driver but I do like to take the car up to the limits when it's dead out and not needing a half mile to stop is awesome.
i guess all the times ive hit 130-140 on track before a sharp turn with blank rotors doesnt count
and just so i can use these: and
#32
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I also have consistent "Peel your face off" braking ability from 130-140 on the track with my blank rotors.. Guess that doesn't count though.. Too bad for us..
#33
Music to my eyes.....I stuck to blanks all the way around recently and resisted everyone's stupid notion and beliefs on cheap lines and holes in their rotors.
You guys should try hearing that kind of stuff from your local meineke store manager who recut a pair of my blanks.....I just stood quietly and didnt even bother while he went on and on about getting slotted and vented rotors and yada yada.....I shook my head and said sorry im not going to do it.......this is a Z28 not a 350Z.
You guys should try hearing that kind of stuff from your local meineke store manager who recut a pair of my blanks.....I just stood quietly and didnt even bother while he went on and on about getting slotted and vented rotors and yada yada.....I shook my head and said sorry im not going to do it.......this is a Z28 not a 350Z.
#34
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Less material = builds up heat faster. Heat is what causes brake fade under hard braking. Also, less material on the surface = less surface area, which creates a smaller swept area and decreases braking force.
As mentioned, the changes you saw were a change in pads, and probably nothing more. To find some more information, search for some of the huge threads that have blown up on here, there's a ton of good information from the people that really know how this stuff works. Also, reading the brake writeups on TireRack or most manufacturers websites is a pretty good idea as well.
The reduction in surface from drilling has no affect on braking force - your master cylinder bore, pedal fulcrum, line pressure, number of caliper pistons, their size and their position relative to the center of the hub is what determines braking force.
At any given moment the only surface area that matters is what's directly under the puck. The reduction in surface area of a typical pad due to slotting and chamfering is much greater than the area lost by drilling.
I do agree with you that the pad compound will have the biggest effect on rate of deceleration.
#36
Please explain why loss from drilling would not equate loss in surface area?
When your talking about a hole vs. thin lines. Either way material is being taken away.
It's easy to say loss of surface area is loss of surface area is loss of surface area. I'm certain the holes equate to some loss of surface area.
#37
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You're wrong about the less material = heat build up. A typical 20+ lb rotor will usually lose about .1 lb of iron during the drilling process. Cross-drilling increases the wetted surface area of the rotor thereby improving itscooling ability. Convection heat transfer is second only to radiation in terms of energy conversion. Conductive heat transfer which you're implying is negatively affected by drilling; is responsible for the lowest percentage of energy conversion. The more airflow through the vanes, the cooler they will run.
So, you're saying that if I take a torch to a 10 lbs. block of material it will heat up faster than if I take a torch to a 9 lbs. block of material that has holes cut in it? Not quite the same as a brake rotor, but the principal remains.
The reduction in surface from drilling has no affect on braking force - your master cylinder bore, pedal fulcrum, line pressure, number of caliper pistons, their size and their position relative to the center of the hub is what determines braking force.
Yes it does. Not in the actual pressure being put on the rotor by the pad, but the actual force that creates the stopping power is reduced by the decrease in swept area.
At any given moment the only surface area that matters is what's directly under the puck. The reduction in surface area of a typical pad due to slotting and chamfering is much greater than the area lost by drilling.
I do agree with you that the pad compound will have the biggest effect on rate of deceleration.
So, you're saying that if I take a torch to a 10 lbs. block of material it will heat up faster than if I take a torch to a 9 lbs. block of material that has holes cut in it? Not quite the same as a brake rotor, but the principal remains.
The reduction in surface from drilling has no affect on braking force - your master cylinder bore, pedal fulcrum, line pressure, number of caliper pistons, their size and their position relative to the center of the hub is what determines braking force.
Yes it does. Not in the actual pressure being put on the rotor by the pad, but the actual force that creates the stopping power is reduced by the decrease in swept area.
At any given moment the only surface area that matters is what's directly under the puck. The reduction in surface area of a typical pad due to slotting and chamfering is much greater than the area lost by drilling.
I do agree with you that the pad compound will have the biggest effect on rate of deceleration.
#38
Points in bold. I'm not saying that drilling/slotting a rotor will make a huge difference, but physics don't lie. When you factor in the increase in stress points in the rotor and the fact that pad life is decreased, I don't see any tangible benefit to a drilled/slotted rotor (unless you're racing and want something to scrape at your pad to keep the surface fresh, where some race cars have small slots cut into the surface).
I have also worked with professional racing drivers who can definitely feel the difference. Once during qualifying at Daytona, drilled rotors were put on the car. Before the morning race warmup, the crew swapped them for slotted rotors in preparation for the 24 hour race -- but neglected to tell the driver. He then blew right through the back straight chicane when there was much less bite. Race pads take longer to heat up and he was surprised there was not enough heat in them yet due to the rotor change.
Are there additional stress risers? You bet. But that makes little difference on the street. I've been in the industry for over 20 years and hardly ever see (properly manufactured) drilled rotors that cracked before they wore out -- unless severely abused or tracked hard. I have seen MANY poor quality rotors (bad casting, substandard materials, wrong thermal post-processing, incorrect drill patterns, poor finishing, etc.) like the typical eBay garbage crack, but that has nothing to do with the drilling question.
Decreased pad life? Yes, a little anyway, but not severe at all. Most street pads are so low in friction that the extra bite that the drilled rotors gets out of them is well worth the trade-off. Pads are relatively cheap and quick and easy to change out, so I've never found it to be an issue.
Contrary to some of the points laid out in this thread, reducing the surface area has absolutely no effect on brake torque. But it does cause the pad and rotor to heat up a bit quicker from cold. The effective torque arm can be viewed at the center of pressure for the pad for calculation purposes. This does not change by drilling the rotor, so no torque is lost.
Also, drilling a rotor typically removes .35 - .70 pounds, depending on the size of the rotor, its design and plate thickness. This is relatively insignificant as far as temperature rise is concerned. Yes, the rotor will run slightly hotter, but good luck actually measuring the change without an on-board data acquisition system.
Chris
#40
But if it helps, all but one of my street vehicles has cross-drilled rotors on it right now. The odd man out is slotted-only, but that vehicle is large and can put lots of heat into the brakes very quickly. Even the family van has drilled rotors, which my wife likes the feel ("oooh, grippy!") of over the stock stuff I took off. Yeah, the pads were 80% of the improvement, but the rotors do contribute some. It may only stop 5 or 10 feet shorter, but that can make all the difference in the world when needed.
For track cars, I prefer the J-Hook pattern. It has the bite of a cross-drilled rotor without the stress risers.
Chris