I don't think stability will be comprimized as much as balance. But I also don't know how bad it will or won't offset the balance.

Originally posted by No4NJunk




Bull****!! ((( Now now,... I said good, or bad, but not ugly )))




If you attempt this don't drive on the road while I'm around.

First: There is more to it than drilling holes!

Second: Why would you want to do this.

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It helps keep the pad clean, wich increases friction during braking.
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It won't help you at all. We don't have asbestos in our pads anymore. That means no more trapped gasses and brake fade. That technology is no longer needed.
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(((Why do they still sell them?))) You've never experienced Brake Fade!?

Obviously you've never driven rush hour on the Dan Ryan in Chicago.
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Third: Wouldn't compromise stability eh......

It helps keep the pad clean, wich increases friction during braking.

((Why do they still sell them?))) You've never experienced Brake Fade!?

Obviously you've never driven rush hour on the Dan Ryan in Chicago.

That crack in your pic looks to me like it is in a severly burnt (black) rotor from an abussive driver. I will not argue that it is possible that the crack is a result of the hole, but it might also be from abuse.

Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the 40’s and 50’s, 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 same 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, the temperatures can actually increase a little), they create stress risers allowing 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.)

Originally posted by my3rdgen
That crack in your pic looks to me like it is in a severly burnt (black) rotor from an abussive driver. I will not argue that it is possible that the crack is a result of the hole, but it might also be from abuse.

If you want a cheap way to improve your brakes, get new rotors, good pads and bleed the fluid. You can probably do this for under $100 if you do the work yourself.

I'm going to have to agree with Robert on this one. I see some of you are experts in braking systems.
The brakes function by converting the kinetic energy of the car into thermal energy during deceleration, producing lots of heat, which must then be transferred into the surroundings and into the air stream.

The amount of heat produced in context with a brake system needs to be considered with reference to time meaning rate of work done or power. Looking at only one side of a front brake assembly, the rate of work done by stopping a 3500-pound car traveling at 100 mph in eight seconds is 30,600 calories/sec or 437,100 BTU/hr or is equivalent to 128 kW or 172 hp. The disc dissipates approximately 80% of this energy. The ratio of heat transfer among the three mechanisms is dependent on the operating temperature of the system. The primary difference being the increasing contribution of radiation as the temperature of the disc rises. The contribution of the conductive mechanism is also dependent on the mass of the disc and the attachment designs, with disc used for race cars being typically lower in mass and fixed by mechanism that are restrictive to conduction. At 1000deg F the ratios on a racing 2-piece annular disc design are 10% conductive, 45% convective, 45% radiation. Similarly on a high performance street one-piece design, the ratios are 25% conductive, 25% convective, 50% radiation.

Repeated hard stops require both effective heat transfer and adequate thermal storage capacity within the disc. The more disc surface area per unit mass and the greater and more efficient the mass flow of air over and through the disc, the faster the heat will be dissipated and the more efficient the entire system will be. At the same time, the brake discs must have enough thermal storage capacity to prevent distortion and/or cracking from thermal stress until the heat can be dissipated. This is not particularly important in a single stop but it is crucial in the case of repeated stops from high speed.

Slotted and/or drilled rotors have less or more contact area then regular ones? Also would slotted and/or drilled rotors have greater or lesser resistivity to heat dissipation that can cause premature cracking from thermal stress? Have you guys seen the Nascar rotor camera? They get red hot in less then 1 sec. They're not even stopping, they're just slowing down a bit for the turn. Plus their rotors are made specifically for racing and high speed braking. Your rotors are made for slow driving. Do a few hard stops and you will see increases in stopping distance. Your brakes haven't had time to cool off yet. They will get soft and respond slower and slower. Now take away 30-40% of the braking and heat storage capacity away. Once the brake fluid inside the caliper has boiled, it has lost a significant percentage of its original boiling point and should be replaced. Yes, it only takes one time.

For many years most racing rotors were drilled. There were two reasons - the holes gave the "fireband" boundary layer of gasses and particulate matter someplace to go and the edges of the holes gave the pad a better "bite".

Unfortunately the drilled holes also reduced the thermal capacity of the discs and served as very effective "stress raisers" significantly decreasing disc life. The advent of carbon metallic friction materials with their increased temperatures and thermal shock characteristics ended the day of the drilled disc in professional racing. They are still seen (mainly as cosmetic items) on motorbikes and some road going sports cars. Typically in original equipment road car applications these holes are cast then finished machined to provide the best possible conditions by which to resist cracking in use. But they will crack eventually. Slotted rotors will fill up with pad material, when the system is operating at too high a temperature.

DOT 3 and DOT 4 brake fluids are ether based and are hygroscopic in nature - i.e. they absorb water vapor. As the braking system in not quite airtight, a significant amount of water can be absorbed from the atmosphere in the course of a year. A 3% water content in brake fluid drops the boiling point as much as 170 degrees F. Brake fluid should be completely replaced annually.

Carbon metallic: This is a trademark of the Performance Friction Corporation. Pad friction compounds containing large percentages of pure carbon along with various metallic elements. Pioneered by Performance Friction Corporation these compounds offer very constant coefficients of friction vs. temperature characteristics along with increased thermal capacity. The disadvantage is that, since they both operate at higher temperatures and their temperature rises to operating temperature faster than other compounds, they increase thermal shock to the disc and increase thermal conduction to the caliper pistons and brake fluid. As a result, it is recommended to not use drilled discs with carbon metallic pads.

Some of you claim that since Porsche and Ferrari use drilled rotors, so for that reason alone they must be better.
From the Porsche source:" A special ventilation system cools the entire braking system using air routed from inlets at the front of the car, thereby ensuring consistent levels of performance and greater longevity, even under the heaviest use. " Do you have a special ventilation system in your camaro to cool your drilled brakes that now require extra air to dissipate heat? The only advantage to cross drilled rotor is the circulation of air, but when there is no air ducts there is no air to circulate.

From Ferrari source:"These brakes are extremely expensive as they are made from hi-tech carbon materials (long chain carbon, as in carbon fibre) and they can take up to 5 months to produce a single brake disk. The first stage in making a disc is to heat white polyacrylo nitrile (PAN) fibres until they turn black. This makes them pre-oxidised, and are arranged in layers similar to felt. They are then cut into shape and carbonised to obtain very pure carbon fibres. Next, they undergo two densification heat cycles at around 1000 degrees Celsius. These stages last hundreds of hours, during which a hydrocarbon-rich gas in injected into the oven or furnace. This helps the layers of felt-like material to fuse together and form a solid material. The finished disc is then machined to size ready for installing onto the car." Can you afford these rotors or are you buying cheap rip offs that are just drilled and were not made for it in the first place?

Summary for car rotors.

These rotors that you are buying are just standard rotors that are drilled full of holes. The structure is weakened and the mass of the rotor is reduced, therefore limiting its ability to deal with heat buildup. Ferrair and Porsche on top of their air ducts have their rotors designed at the casting stage to be cross-drilled. They have thicker rotor surface sections and more material in the cooling slots. They are stronger to begin with so they will hold together longer despite the cross-drilling. Do you have any idea as to cost of their brake systems? I could sell my car and still not afford their rotors. But of course the $100 special from some vendor that knows nothing of braking will yield simial results. Keep dreaming.

Slotted rotors will increase pad wear. Just think about this one so I don't have to explain it.

Yes, bikes can afford to have cross drilled rotors because they weigh 400lbs, not 3400lbs. My car is around 3000lbs now and I can already notice a huge difference in braking power from when I was stock weight. I can only image how much less rotor would I need to stop if I dropped another 2600lbs. On top of that bike has 2 rotors and I have 4. And you dare to compare the two? On what basis? And lastly their brakes are probably made just like I stated above, with cross drilling in mind. Not solid that were later cross drilled. It helps with stopping in the rain. On bikes it doesn't matter since there is plenty of stopping area. Those that say bikes have them so they must be good, have you ever rode a bike? I have many times. They stop on a dime. You can't even realize the stopping potential due to tires being the weak point.

Alright I said enough. Lot of quotes above from braking specialists not people who just sell them.

((Why do they still sell them?))) You've never experienced Brake Fade!?

Obviously you've never driven rush hour on the Dan Ryan in Chicago.