difference between slotted brakes and drilled brakes

[iracemine]

best rotor ever for 35 bucks for front and 29 bucks for rear!!!! i would want to see any studys or results with any sl/cd rotors vs plain rotors on OUR cars before i puked out any more money. pads are a littil trickey some might sqeek bad and some dust really bad so be carefull.

 

[Mazda_maniac]

I believe this is a battle that will never be settled. It will all come down to personal opinion, noone here has the time nor money to do adequete testing. I have a few responses and will explain my opinion as well. I believe they are utterly useless as well. Here we go.....
First off cross drilled and slotted supposebly vent the gasses created under hard braking... with the new technology and compounds being used in ceramic, metallic, and carbon pads the temperature that these will change state is very unlikely to be reached. These compounds all have a very high temperature at which they will boil/evaporate. This also addresses the case of slotted rotors slicing off the glazing on pads. In order to reach this temperature there needs to be a very high amount of kinetic energy to create this temperature. Our cars are light and don't have a very high maximum speed(forgive me on this if you have it turboed or something along those lines). Therefore there is not much kinetic energy to stop. Now onto how they could actually be a disadvantage. A brake acts as a heat sink, drilling holes or cutting slots remove the total mass of the brake. Yes maybe the weight will affect the cars performance but that weight is directly linked to a greater change in conductivity than the actual need of less kinectic energy to get the vehicle moving the same speed. With less mass to the rotor, the heat sink is diminished, then less heat can be dissapated from the pads. This difference will actually cause the pads to operate at a higher temperature. I believe the only reasonable upgrades are lines, pads, rear disc conversion or shoe upgrade. If you got the cash big brake, they have a greater area so they act as a better heat sink, so there's even less heat on your pads. The surface area will not effect the coefficient of friction, its all basic physics. The le mans cars are vented because they have an enormous amount of kinetic energy so they do produce the very high temperatures to cause gasses, and the rotors are also gigantic to allow a happy medium between lost heatsink, and ability to vent gasses.
There is my personal thoughts on this controversial topic, i hope i wasn't too all over the place.

 

[iracemine]

exactly what i was trying to say! im just not as linguistic(first)

 

[DaveMS307]

Personal experience...

Drilled are no good. Bought a "premium" brand that developed cracks after the first track weekend (heavy braking from 110-120mph). Stock rotors resulted in glazed pads. Solution for me that lasted 1.5 years of driving and about 8 or 9 track weekends - slotted. Used more pad, but kept them from glazing. Slot was the type that did not go to the edges.

For heavy use on track drilled worked fine for the rear - slotted in front.

For street driving, stock rotors are all you'll need and will not see any benefits from drilled/slotted except cosmetic.

This was from my SVT Focus, but I believe the same would be true for my 3.

my 2 cents...

 

[Hughes412]

Mazda Maniac you are right on one thing. There is not end to this. You all will think what you think and unless some one sits you down and shows you in person you wont change your mind. But I will say you are way off. Agin it the didn't work why would the big guys use them? Why wouldn't they just make a real big rotor and pad? And our cars are not light. they are over 3k pounds. My suggestion (and it shouldn't be hard is to go find someone with S/D rotors and compare. As for the topic, if you are getting some get both.
And DaveM, your rotors were just defective plan and simple.

 

[BKK Jack]

Inertia would not be a factor in braking, because inertia is a mass' resistance to motion. As in motionless. It is what I possess on a lazy Sunday afternoon in my recliner. Once inertia is overcome and a mass is set into motion that mass has MOMENTUM.

I only bring this up because I have seen inertia incorrectly switched for momentum several times, and it bugs me a little. Sorry for the interruption, please continue your discussion...

Shortly after posting this, I received a private message from sss37, which read:

You know what bugs me is people who correct people incorrectly.
Inertia: resistance of a mass to any CHANGE in motion.

From Isaac Newton: "Every body perseveres in its state of being at rest OR of moving uniformly straight ahead, except insofar as it is compelled to change its state by forces impressed." [Cohen & Whitman 1999 translation]

So, when used in the context that you are commenting on, inertia and momentum are the same thing. This IS a correct usage of the word inertia.

Applied Physics Major, Cornell University.

He was kind enough to correct me privately, but I thought it would be better everyone see this.

 

[iracemine]

waist on thies cars: 3

if it works on a vette it should work on mine: 1

 

[Hughes412]

Shortly after posting this, I received a private message from sss37, which read:



He was kind enough to correct me privately, but I thought it would be better everyone see this.

Who knew?(jerkit)

 

[FreewheelBurner]

Cross Drilled and Slotted should be for show only, they have the cons of both as well as having much less surface contact. Of all the cross drilled rotors i've seen on cars half of them had cracks, and that was because those cars were driven. Slotted rotors work great for their short time, but they cause faster pad wear and eventually cake themselves full with break dust.

If there is anything in getting better performance from brakes then it would be mainly the pads, they do the gripping and their quality effects performance more than anything else.

 

[iracemine]

waist on thies cars: 4

if it works on a vette it should work on mine: 1

 

[Mazda_maniac]

What i previously said about the le mans cars is basic physics. They move at a much greater rate than a protege. Therefore probably creates enough friction that causes a high enough temperature to conisistently change the state of the pads. The larger size of the rotor is to more or less counter act the loss or the heat sink. More basic physics..... The surface area will not affect the coefficient of friction between two surfaces. Also think of it this way, if you made rotors that were cross drilled, of course you would advertise them as beneficial. It's normal business practice to stretch the truth. they won't say buy our rotors they only look pretty and are probably utterly useless. Another point on the big brakes. They are no longer a floating caliper, therefore with more than one piston the pads are applied evenly and at the same time comparitive to the floating caliper.

 

[Hughes412]

Cross Drilled and Slotted should be for show only, they have the cons of both as well as having much less surface contact. Of all the cross drilled rotors i've seen on cars half of them had cracks, and that was because those cars were driven. Slotted rotors work great for their short time, but they cause faster pad wear and eventually cake themselves full with break dust.

If there is anything in getting better performance from brakes then it would be mainly the pads, they do the gripping and their quality effects performance more than anything else.

See, this is what gets me, You don't know what the hell you're talking about. I've had mine on for over 30k miles, and I've got 55k on the factory pads. I drive 35-40 mins to work and it's 16 miles, that means stop and go. In the after noons that turns to a 60 min drive. I've had this car the almost as long as my job (4yrs). If they crack that should teack you not to buy cheap ebay s***. There is not enough of the rotor surface taken off to mess with the stoping distance. That would kind of defeat the purpose.

 

[Hughes412]

waist on thies cars: 4

if it works on a vette it should work on mine: 1

Don't know what you are talking about people 4

Bake Check manager and ASE certified mechanic 1

As stated, I highly doubt that multi million dollars companies would sell these rotors if there was a chance that they didn't work or even worse if they cracked. And it wouldn't take to much work for you smart guys to do a little research.

 

[Hughes412]

I guess sense these all pretty much say the same thing all of the engeneers went to that same school and don't know what they are talking about.(RTM)

Rotora's performance brake discs are designed to meet the challenges of road racing while offering the best combination of cooling and out-gassing of performance discs. Available in cross-drilled, slotted, or cross-drilled and slotted pattern, Rotora's performance brake discs exceed all vehicle manufacturers' specifications to ensure maximum heat and gas dissipation for greater stopping power and minimize cracking caused by repeated, high-stress, high-temperature braking.

Many high-end super cars now come with combination slotted/cross-drilled rotors as standard equipment, and with good reason. They provide the benefits of slotted rotors, i.e., a large active surface area and slots that wipe away gases, dust and water, but also gives the driver the benefits of cross-drilled rotors, quicker heat dissipation and lower unsprung weight. Cooler rotors are less susceptible to brake fade and glazing, major causes of decreased brake performance. Cooler discs also are less likely to warp, which can cause vibration, squeaking, and/or uneven brake wear.

In racing drilled rotors are used to cure "pad fade" when there is no possibility of either fitting bigger brakes or using higher temperature pads. Pad fade occurs when the pads get so hot that they start outgassing and the resulting gas causes the pads to float above the discs like an air hockey puck. The drilled rotors cure this by letting the gas out.


StopTech has incorporated several design innovations to improve rotor airflow, cooling and heat capacity. The ability to absorb and dissipate heat is essential to brake system performance. The uniquely designed vanes inside the disc optimize airflow through the rotor. This improved directional design minimizes turbulence and flows more air than any rotor tested. Better Airflow means better cooling and less fade.

SportStop one-piece direct replacement rotors fit stock calipers. Drilling or slotting helps wipe away the debris that forms between the pad and the disc, adds more bite, and can help the rear brakes to match the aesthetics of a front big brake kit. The rotor finish helps prevent glazing of the pads and improves wet and dry braking performance. Most StopTech rotors have a durable black coating on the non-swept areas of the rotor to prevent unsightly corrosion. Quality is assured as the rotors are manufactured to meet or exceed all OE specifications.

Q: Noah from Chandler, AZ owns a 2000 Saturn SL1 and writes: I have done quite a few upgrades to my car, and have yet to upgrade the brakes. I wanted an opinion on whether I should get slotted or cross-drilled rotors. What are the benefits of the two? Should I do a combo thing, and put the slotted ones on the back and cross-drilled ones on the front, or the other way around? Should I just stick with the same type on all four wheels?
A: Our friends at Power Stop Autospecialty (800 E. 230th St., Carson, CA 90745, 310-513-2060,www.autospecialty.com) have told us that on the street, cross-drilled rotors are the way to go. Slotted rotors tend to wear out the pads very quickly, which is not what you want on a street car. They are put to better use on race cars where the wearing of the pads can keep them from glazing during a race.
Power Stop says its cross-drilled rotors perform great at high brake operating temperatures and high speeds. They are engineered for superior stopping, high fade resistance and long pad life. They also have excellent front to rear brake balance for maximum vehicle control and stability. Using them in the front and the rear would give you the ultimate brake setup. However, if you can only afford to do one end of the car at a time, do the front first.

For drivers who demand better than OEM brakes, Power Stop more than delivers! Power Stop brake rotors do not require a costly brake overhaul to get great results and simply replace your old and rusty stock rotors. To ensure maximum braking performance and safety, Power Stop offers braking solutions that are designed to meet the braking requirements specific to vehicle type and use. All Power Stop rotors are sold individually.

Power Stop provides three different rotor options so that your vehicle can deliver the perfect braking performance for your driving style and budget:

Slotted
The slots on the Power Stop slotted rotor are engineered to reduce brake fade by providing an escape path for the gasses emitted from the brake pads under extreme braking conditions as well as dispensing built up heat. In addition to the de-gassing and cooling benefits, the Power Stop slotted rotor design improves braking under wet conditions as the water is swept through the slots and keeps the pad surface clean which reduces brake dust. Slotted rotors are coated with a shiny, silver zinc dichromate finish to prevent corrosion and maintain the new rotor look.

Cross Drilled Rotor
The Power Stop cross drilled rotor series are engineered designed to provide increased cooling versus a slotted only rotor. A vented rotor can be viewed as an air fan. When in motion, the vents draw from the center of the rotor outward. This airflow, over an increased internal surface area, very effectively dissipates hear. Cross drilling adds to this airflow, as well as providing additional surface cooling. It also helps the rotor to cool more evenly, eliminating hot spots and greatly reducing brake pulsation. Cross Drilled rotors are coated with a gold, zinc dichromate finish to prevent corrosion and provide a new rotor look.

Cross Drilled & Slotted Rotor
The cross drilled and slotted series is engineered to provide maximum heat dissipation for dependable and safe braking under extreme braking conditions. Short of replacing your braking system for a big brake kit, Power Stop's cross drilled and slotted Extreme Performance rotors provide maximum braking performance without breaking the bank! Dyno tests on a vented Mustang rotor show a heat reduction of 50-200F when comparing a Power Stop cross drilled rotor and slotted rotor to the OE designed rotor. Because the Power Stop cross drilled and slotted rotors are running at a lower temperature, this allows for greater braking power, and in many cases, longer rotor and pad life. The combination of the cross drilled holes and the slots are constantly enabling the braking surface to be cleaner thus providing improved friction bite and cleaner wheels. Cross Drilled and Slotted rotors are coated with a gold, zinc dichromate finish to prevent corrosion and maintain the new, bold rotor look.

 

[Mazda_maniac]

I believe I'm also a trained technician and on the road to a bach of science with a major in automotive technologies so if you want to bring that into relevance get a life. The industry is ever changing. I voiced my opinion you voiced yours neither of us have the money to do adequete testing. So before you go off telling us we're all morons think about what your saying. It's much easier to think you know everything than to admit you might be wrong. If you know all about the engineering aspects then why aren't you an engineer, why don't you work for a performance branch of a major manufacturer adviseing these rotors. Get over yourself. I may be wrong and you may ******* be wrong. Just open your eyes and stop acting like a ******* engineer, you sure got the mentality thinking you can get off saying we know nothing. Look all overr the web there is huge controversy over this very topic. When you've tested all the different rotors, on over 300 proteges with the same pads, then you can tell us what works better and that we are morons til then shut the **** up and voice an opinion while respecting others.

Also ever heard what the companies are about? would they be alive if they never sucked your money out? NOPE. Welcome to planet earth. I believe if you would look a little deeper at things like slick 50 their pathetic tests prove nothing. Everything they say will be very biased, there are very few companies that are 100 percent truthful in the end they want money that's all there is to it.

prove my previous points wrong with relevant SCIENTIFIC EVIDENCE and my opinion may change, all your evidence is straight off the rotor manufacturer sites. Of course they are not going to say the disadvantages. Show some more relevant info and my opinion may budge, I am not a close minded person but have just seen more information pushing me into the direcction I am in.

 

[Hughes412]

I believe I'm also a trained technician and on the road to a bach of science with a major in automotive technologies so if you want to bring that into relevance get a life. The industry is ever changing. I voiced my opinion you voiced yours neither of us have the money to do adequete testing. So before you go off telling us we're all morons think about what your saying. It's much easier to think you know everything than to admit you might be wrong. If you know all about the engineering aspects then why aren't you an engineer, why don't you work for a performance branch of a major manufacturer adviseing these rotors. Get over yourself. I may be wrong and you may ******* be wrong. Just open your eyes and stop acting like a ******* engineer, you sure got the mentality thinking you can get off saying we know nothing. Look all overr the web there is huge controversy over this very topic. When you've tested all the different rotors, on over 300 proteges with the same pads, then you can tell us what works better and that we are morons til then shut the **** up and voice an opinion while respecting others..

The only people that think these rotors do nothing are people like you. People that are not in the industry or kids that want to be mechanics. While you might be going to school that doesn't mean crap to people that have been doing the work for yrs. Ask real drivers or auto motive engeneers not the punk kid down the road.
Oh and just for your info I went from working as a full line mechanic to a manager of both full auto shops to specialty shops. After that I went into machining for 8 yrs. I decided to get a better job with better pay and better hours with better benifits. I now work for the state originating home and land loans. So to answer you question, I've been there.
Oh and A TRAINED TECHNICIAN is what you find in walmart, big whoop!

Also ever heard what the companies are about? would they be alive if they never sucked your money out? NOPE. Welcome to planet earth. I believe if you would look a little deeper at things like slick 50 their pathetic tests prove nothing. Everything they say will be very biased, there are very few companies that are 100 percent truthful in the end they want money that's all there is to it.

While part of this is true Slick 50 is totally different then steal rotors! I don't see indy cars or La Mans cars using it, but you do see them using these rotors. So like your opinion, the comparison is off. It's not hard to disprove your claims of these rotors being bad. One I rotate my tires every other oil change, I see no cracks! To I did do a before and after 60mph to 0 stop and while I cant remember what the number was it was noticable shorter then the stock rotors. I did a how to on here, you can look that up also.

prove my previous points wrong with relevant SCIENTIFIC EVIDENCE and my opinion may change, all your evidence is straight off the rotor manufacturer sites. Of course they are not going to say the disadvantages. Show some more relevant info and my opinion may budge, I am not a close minded person but have just seen more information pushing me into the direcction I am in.

WTF dude, SCIENTIFIC EVIDENCE! Give me a freaking break. You act like we are debating Space/Time Continuum. You know some things just aren't that hard to explan. Your over thinking this s***. But that's because you don't know what your talking about. How about you listen to the people that put their lifes work into a product and not the kid that THINKS he's a profesional racer with all of his parking lot auto cross time.

 

[Hughes412]

When you've tested all the different rotors, on over 300 proteges with the same pads, then you can tell us what works better and that we are morons til then shut the **** up and voice an opinion while respecting others.

prove my previous points wrong with relevant SCIENTIFIC EVIDENCE and my opinion may change, all your evidence is straight off the rotor manufacturer sites. Of course they are not going to say the disadvantages. Show some more relevant info and my opinion may budge, I am not a close minded person but have just seen more information pushing me into the direcction I am in.

I do not think I ever came out and said you were a moron. However, with some of your statements you have proven that to be a valid assumption!

If you read the how these rotors work youll see that the drilled and slotted rotors are best for people that can not afford to go to a big brake system. Kind of like me as I only have front rotors and there is no system made for me. Now if you can find a big brake system and you can afford it, yes that would be better then running stock size D/S rotors. Thats just commonsense. As for me being wrong, no I dont think so. I think Ill stick with the thousands of real racecar teams and professionals over a bunch of wanabes any day.

BIATCH!

 

[Hughes412]

Got the brakes done this past weekend and the difference is def noticeable. Def a good upgrade if anyone is contemplating swaping out the factory rotors and pads.

I guess this guy is wrong too.
http://www.mazdas247.com/forum/showthread.php?t=123645669

 

[Mazda_maniac]

The only people that think these rotors do nothing are people like you. People that are not in the industry or kids that want to be mechanics. While you might be going to school that doesn't mean crap to people that have been doing the work for yrs. Ask real drivers or auto motive engeneers not the punk kid down the road.
Oh and just for your info I went from working as a full line mechanic to a manager of both full auto shops to specialty shops. After that I went into machining for 8 yrs. I decided to get a better job with better pay and better hours with better benifits. I now work for the state originating home and land loans. So to answer you question, I've been there.
Oh and A TRAINED TECHNICIAN is what you find in walmart, big whoop!


While part of this is true Slick 50 is totally different then steal rotors! I don't see indy cars or La Mans cars using it, but you do see them using these rotors. So like your opinion, the comparison is off. It's not hard to disprove your claims of these rotors being bad. One I rotate my tires every other oil change, I see no cracks! To I did do a before and after 60mph to 0 stop and while I cant remember what the number was it was noticable shorter then the stock rotors. I did a how to on here, you can look that up also.


WTF dude, SCIENTIFIC EVIDENCE! Give me a freaking break. You act like we are debating Space/Time Continuum. You know some things just aren't that hard to explan. Your over thinking this s***. But that's because you don't know what your talking about. How about you listen to the people that put their lifes work into a product and not the kid that THINKS he's a profesional racer with all of his parking lot auto cross time.

Oh your a class act. I believe the person that would know a fair amount would be an instructor, the same type of person that trained you at one point. What I was saying was it's all based on opinion. Yes maybe they will help, and maybe they won't. If you weren't such a prick about you "experiance" and realize some things it is physics. There are some things that prove them as being bad and some that prove them as good. The brake pads in the industry are ever changing and developing, until your a le mans engineer, mechanic, or driver, stop using this as a comparison unless you really know ever bit to do with the rotors they use. That's great you have experiance maybe it'de teach you to be a little more understanding cause I'de hate to see how you treat your customers. There's a difference between saying your wrong and saying from my understanding. We're all human, we are all wrong sometimes get the **** over it. Scientific evidence is the only guaranteed proof, a test sample that has the elements consistent will show, until you've shown this my opinion is mine, yours is yours. My point about less mass still stands! IT'S BASIC PHYSICS!!!!! when you heat up a 1/2" steak on the grill does it cook faster or slower than a 3/4" maybe think more about possibility than how your right. I know I'm not sitting here saying to myself he's so wrong. I'm stating my thoughts and until disproven correctly I'm allowed to have them. I'll let my teacher know that he's just some stupid kid down the street. I forgot only the people in the industry know what they are talking about. I also forgot that since you can't afford big brakes that the race teams and professional drivers don't use them! Very valid point there Mr. experienced. You apparently never read my point about the racers finding a happy medium with rotor size and the mass slotted or drilled. How bout that 60-0 time, did you happen to use different pads, change your fluid, lines, or alter it in any way before that? I'm betting so otherwise reall classy rotors but nothing else. Also if your that far in life and your still more worried about being 100 percent right and making other people feel downsized maybe you should take a look around. Your acting like that kid racer down the street.


Guys that might be right:4

Guy that might be right but has his head up his ass:1

 

[iracemine]

Lol!!!!!