Drilled Rotors need advice
06-04-10, 08:46 PM
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Drilled Rotors need advice
Want to put drilled roters on my 07 is350 where can i buy some from need advice on who sells them and keep my stock brake calipers for the front brakes only . thanks
06-04-10, 08:56 PM
#2
So you don't plan on keep the rear brake calipers? Are you confused with a BBK?
As far as drilled rotors, here a few companies that make them; Stoptech, Brembo, Powerslot, 88rotors, and that's all i can remember off the top of my head.
May i ask why you want drilled rotors?
As far as drilled rotors, here a few companies that make them; Stoptech, Brembo, Powerslot, 88rotors, and that's all i can remember off the top of my head.
May i ask why you want drilled rotors?
06-05-10, 01:51 PM
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drilled weakens the rotor and if you run them hard enough you will get cracking around the holes. but a street car doesn't run them hard enough for cracking. also provides less surface area for the break pads which means less friction. they run them in racing still because the brakes are already more than powerful enough to overpower the tires, and its helps with heat and gas dissipation. honestly though it doesn't really make a noticeable difference to hurt performance and they look so pretty. and having said that it will make you smile every time you see them because they look so good. so go ahead and get them.
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06-05-10, 02:14 PM
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drilled weakens the rotor and if you run them hard enough you will get cracking around the holes. but a street car doesn't run them hard enough for cracking. also provides less surface area for the break pads which means less friction. they run them in racing still because the brakes are already more than powerful enough to overpower the tires, and its helps with heat and gas dissipation. honestly though it doesn't really make a noticeable difference to hurt performance and they look so pretty. and having said that it will make you smile every time you see them because they look so good. so go ahead and get them.
They don't even run them on race cars, and brake pads haven't had outgassing issues since the 1950s. (seriously, check out Nascar or F1, they know why drilled sucks).
Slotted for the track, they offer some benefits without weakening the rotor nearly as bad as drilling holes. There's folk on here that can show you pics of the cracks in their rotors after a single day at the track on drilled rotors.
Blanks for the street as they don't sacrifice mass (which is important in something that is basically a heat sink) and offer the longest service life.
Drilled is inferior to either except cosmetically.
06-05-10, 04:07 PM
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They definitely still run them on racecars. every porsche gt3 cup car that races has them. if race rules dont allow for carbon ceramic brakes, and only allow for cast iron rotors, then you have to run with drilled or slotted rotors for heat. it all depends at that point upon who your supplier/sponsor is for the race series.
drilled is superior to slotted for dissipating heat and thus avoiding brake fade, but they do crack very quickly. ive replaced far too many to count (but those are on gt3 cup cars after alms races).
Both will eat your pads faster than blank rotors, but both offer improved heat dissipation and good looks. If you go drilled get a high quality set, low quality sets crack quickly. whereas a high quality set you really have to thrash to get cracks to form. so as long as your not an uber track guy then a good set wont crack.
Also i was wrong in that they would offer inferior braking, i forgot that surface area has no effect on friction forces.
drilled is superior to slotted for dissipating heat and thus avoiding brake fade, but they do crack very quickly. ive replaced far too many to count (but those are on gt3 cup cars after alms races).
Both will eat your pads faster than blank rotors, but both offer improved heat dissipation and good looks. If you go drilled get a high quality set, low quality sets crack quickly. whereas a high quality set you really have to thrash to get cracks to form. so as long as your not an uber track guy then a good set wont crack.
Also i was wrong in that they would offer inferior braking, i forgot that surface area has no effect on friction forces.
Last edited by kannon; 06-05-10 at 04:12 PM.
06-05-10, 08:57 PM
#10
They definitely still run them on racecars. every porsche gt3 cup car that races has them. if race rules dont allow for carbon ceramic brakes, and only allow for cast iron rotors, then you have to run with drilled or slotted rotors for heat. it all depends at that point upon who your supplier/sponsor is for the race series.
drilled is superior to slotted for dissipating heat and thus avoiding brake fade, but they do crack very quickly. ive replaced far too many to count (but those are on gt3 cup cars after alms races).
Both will eat your pads faster than blank rotors, but both offer improved heat dissipation and good looks. If you go drilled get a high quality set, low quality sets crack quickly. whereas a high quality set you really have to thrash to get cracks to form. so as long as your not an uber track guy then a good set wont crack.
Also i was wrong in that they would offer inferior braking, i forgot that surface area has no effect on friction forces.
drilled is superior to slotted for dissipating heat and thus avoiding brake fade, but they do crack very quickly. ive replaced far too many to count (but those are on gt3 cup cars after alms races).
Both will eat your pads faster than blank rotors, but both offer improved heat dissipation and good looks. If you go drilled get a high quality set, low quality sets crack quickly. whereas a high quality set you really have to thrash to get cracks to form. so as long as your not an uber track guy then a good set wont crack.
Also i was wrong in that they would offer inferior braking, i forgot that surface area has no effect on friction forces.
They're inferior for street use as they have less mass.
A rotor is a heat sink.
In normal street driving you're not constantly braking from 100+ mph multiple times in rapid succession...
You might need to do so ONCE though in a panic stop.
In which case you'd rather have the rotor that can hold more heat (the blank) than the one that would run out of heat capacity sooner (the drilled).
That's apart from the blanks being easier on pads and lasting longer.
On the track slotted'll work well and require replacement a whole lot less often than drilled as you note.
(sorry on the "not used in racing", I was talking about racing where you're not as restricted on using better parts like say NASCAR or F1... as you note you're only using drilled rotors because you can't use better ones like carbon ceramics)
Or just to quote from well-loved brake info source Pulp Friction-
Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." These gasses then formed a thin layer between the brake pad face and the rotor, acting as a lubricant and effectively lowering the coefficient of friction. The holes were implemented to give the gasses somewhere to go. It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads.
For this reason, the holes have carried over more as a design feature than a performance feature. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it.
Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)
For this reason, the holes have carried over more as a design feature than a performance feature. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it.
Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)
Last edited by Kurtz; 06-05-10 at 09:00 PM.
06-06-10, 12:08 AM
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either rotor can hold more than enough joules of heat for one panic stop. and actually drilled rotors will stop in an infinitesimally shorter distance since they have less mass and therefore a lower polar moment of inertia.
honestly it really doesnt matter. if you get a high quality set of drilled rotors they wont crack during street use. all they will do is slightly speed up brake pad wear. there are no negatives to using good quality drilled rotors except for that.
so if you want the look of drilled then go for it. cause they look real good.
honestly it really doesnt matter. if you get a high quality set of drilled rotors they wont crack during street use. all they will do is slightly speed up brake pad wear. there are no negatives to using good quality drilled rotors except for that.
so if you want the look of drilled then go for it. cause they look real good.
06-06-10, 08:00 PM
#12
It also depends on the quality of the drilled/slotted rotor. Rotors that are cast with the holes/slots fare better than those that are cast as blanks and then drilled/slotted out.
06-06-10, 09:38 PM
#13
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Yeah, Brembo drilled rotors look awesome after one track weekend.
06-07-10, 01:02 PM
#14
Lexus Test Driver
^^ LOL....
but seriously...it looks like there are tiny cracks even through the solid portions of the disc.
Maybe your brembo's were a less than perfect batch?
but seriously...it looks like there are tiny cracks even through the solid portions of the disc.
Maybe your brembo's were a less than perfect batch?
