Here's another quote from Baer, I posted the link earlier, bottom of page two.

"Will slotting or cross-drilling my stock rotors improve my car's stopping performance? DEFINITELY NOT! Cross-drilled or slotted rotors do produce a strong visual appeal behind a modern open wheel, and they do have a performance edge when pad outgassing occurs. Outgassing occurs at extreme temperatures when the bonding agents that hold the pad material together break down into a gas form. This gas creates a pneumatic barrier between the rotor and the pad, reducing friction. Cross-drilling or slotting creates a path for the outgassing that occurs during extreme braking conditions. However, these conditions can virtually never be reached on the street! Short of a complete system, performance brake pads, a proper Teflon lined braided stainless steel hose set and quality brake fluids are the only direct replacement upgrades that can be combined to deliver measurable stopping improvements in the context of direct replacement components on the OE brake system."

Brembo's site lacks a FAQ section so I'm not endorsing any brake company over the other, just website had a FAQ.

Speaking of FAQ's here's a quote from Wilwood's FAQ.

"A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage; however, for street and occasional light duty track use, they will work fine. For more severe applications, we recommend slotted rotors."

 

Yea, what ^ he said

 

I have to disagree with "use blanks and blanks only". Further, while I agree Brembo's are the best true blanks generally, I've had GREAT luck and response with the ATE's.

I said it before, and say it again. I'm not a drilled rotor fan. You loose a lot more swept area than you do with slots or have with blanks, and you compromise the structure of the rotor to a much greater degree. I also don't think all slotted rotors are equal, and some suck. Be it from a cheap rotor, or a poor method of slotting. The ATE's are neither cheap, or poorly done. The funky pattern is so you have not stress risers (no sharp points) which is where cracks start. They are not slotted deeply at all. Only down to minimum wear spec only so you are not "weakening" the rotor becuase when down to the spec that they warrant replacement, they are actually blanks as the slots have worn away. And the bonus is they are coated too.

I continue to sell Brembo because some want blanks. Maybe they don't want the slotted look, whatever. But I've yet to have an ATE heat-check like I've seen some Brembo's do (and in fact saw pics of in this thread). And it should be noted that Brembo's have been bounced around, made various places of the last few years, and frankly I don't think the QC is as tight as it was.

And here's the final point. Through the end of the month, we're doing ATE's with free shipping. While the rotor set does cost more than Brembo, the savings you get from not paying to ship 80 pounds worth of rotors actually makes the ATE's less expensive to the door.

Right now I have 8 sets of fronts, and 6 sets of rear LS1 f-body rotors in stock on this deal. If I need more, I'll get more. $354 for a set of 4 ATE PremiumOne rotors... that's a pretty sweet deal.

 

Good info.
I like the "final point"...
Free shipping and $354 is a good deal.

 

I haven't read through all of this yet, but there isn't anything wrong with Drilled/Slotted rotors as long as you buy a quality rotor.

I believe slotting is far more functional than drilled. Drilled is a thing of the past when they used asbestos pads, which created a lot of gas. They drilled the holes to help the gas escape. They've found that slotting basically does the same thing with out compromising the integrity of the disc.

With today's pads, you could race with blanks and be fine. If it's looks you're after, then buy the drilled & slotted. Just buy decent quality and you should be fine. Cracking comes from abusing **** discs.

Also, you should be on the lookout for good materials in your Disc. Try to find some Molycarbide discs, which are usually found on OEM porsche's Lambos etc. The next step up would be Ceramic, if you can afford that.

Check out DBA. They make some bitchin' Molycarbide discs.

 

No you didn't read through the first page so I'll post it again These are "quality" Brembo rotors and definitely not "**** discs" and they cracked up nicely don't you think?

 

Yeah I think sometimes these threads get taken out of context. Almost like people think we're saying drilled rotors are going to explode only after a few thousand miles. Obviously people have been using them for years. We're just saying that may not make it through the normal wear lifetime without developing cracks. Cheaper crap rotors probably are more likely to develop cracks than a higher quality piece. For people who want to use them for daily driving, just inspect them once in a while. But if the question is if blanks or drilled rotors would be better for overall braking performance, then we're going to say blanks over drilled.

I actually had thought that Sam would have said blanks were the way to go, but that may just have been the fact that for many years the best afforable option was just Brembo blanks. So I made the assumption that we were talking about blanks being the best bet for high performance enduring rotors.

 

We use Wilwood drilled rotors here at our shop and have yet to have issues with them. I think the Answer is no one knows. They might crack, they might not. Shrug

 

The process starts with gradually freezing the brakes to -300F over a 12 to 16 hour period in a liquid nitrogen filled cyro-processing machine (see above picture) at Control Thermal Processing Inc. We have selected Control Thermal Processing Inc as our exclusive cryogenic processing partner due to their long, successful track record in treating automotive parts for race team?s country wide. Please visit their website at www.metal-wear.com .for a comprehensive insight into the science of cryogenics. The 2nd step is to gradually ramp up the temperature back to room temperature usually this cycle last for 8 to 14 hours. The 3rd step is the metal tempering phase or as commonly referred as heat treating. This process is very critical, if not done properly the whole cryogenic process will be mitigated. The cycle time for this phase usually lasts 3 hours and the temperatures increases as much as 1100F. The purpose of this step is improving the hardness of the newly formed primary martensite which will be brittle after the cryogenic phase. It must be properly tempered back to increase the hardness. When completed the crystal microstructure of the metal has been altered to enhance wear, reduce abrasion, reduce stress risers and resist metal fatigue.

In simple terms, it makes a stronger longer lasting rotor.

There is a proper way to drill them, basically no more than one hole per cooling vain, and don't penetrate the fins in the rotor so you do not cause structural damage to the rotor. Some manufacturers also chamfer (sp?) the drill holes to prevent hot spots from building up around the holes itself and preventing stress risers. This greatly improves the resistance to developing hairline cracks from the drill holes. There are many tests proving the benefits of drilling and they are far more than just looks, yes they have more of a chance of cracking than a blank casting, on that not however i have personally seen and also have seen on these forums pictures of blank rotors that have cracked under stress in the same fashion that many people claim will happen with the drilled. You will destroy any rotor under heavy track use, that's just the truth.

You are right why would they sell something and market them as performance brake rotors if they did not show some benefit. There are many SAE engineers that support drilling rotor, and as you said many road race cars that use them with out problems, since people want to use websites for resources:

According to PowerStop's website:
"There are three modes of heat transfer, 1) convection {air flow}, 2) conduction {mass}, and 3) radiation {electro-magnetic waves}. When you apply the brakes you convert the kinetic {moving} energy of the car to heat. A moving vehicle has a lot of energy so it is not uncommon to see temperatures over 1000 degrees F. On the street, about 25% of the heat is removed by conduction, 25% by convection and 50% by radiation. At high speeds, the ratios shift to about 15% conduction, 40% convection, and 45% radiation. Therefore, during high speed stops, convection heat transfer [i.e. how air flows over the rotor] plays a very important role. This is where drilled rotors significantly improve convection heat transfer to lower the brake temperature up to 200 degrees. During panic stops on the highway, this can help stop your car 6 to 20 feet shorter."

and yes they do recommend the drilled for street use and also mention similar about racing with the drilled rotors:
"While slotted rotors do not improve brake cooling, they provide a nice cleaning action to wipe away friction debris. Friction dust and gas gets sandwiched between the pad and the rotor, and this can reduce pad bite. Independent tests show that slotted rotors do not improve the brake performance as much as drilled rotors, but they are structurally stronger to handle severe thermal shock. Power Stop recommends our slotted rotors for racing, and heavy duty applications like hauling, towing, and fleet use."

 

I'm a skeptic... And when PowerSlot starts talking about "racing with drilled rotors" I tune out. Hardly anyone races with drilled rotors anymore. And I can assure you if they ran cooler and did all the whiz-bang things they claim--folks would race on them.

The loss of swept area is too great. The fact you disrupt the air flow through the vanes is another.

 

Why would someone sell something claiming to be a performance benefit? Because that's how this game is played. We all know that in every aspect of our lives, any time we buy anything the person selling it claims it be the right thing for the job. How often do you read about a product and it says "not really very good, but it looks cool"? Never. When in doubt research and good old common sense must take over.

This is where I get in trouble. I'm beat on for heavily promoting the products I believe in because I firmly believe them to be the best. Meanwhile I sell the other stuff because I know not everyone will buy what I prefer, and I think it's important to show them I can offer them other things--and that I'm not recommending A because I can't sell them B.

Again, I go back to the point that real racing cars, cars that make the rotors glow from heat, next to NEVER run drilled rotors. If drilling was the panacea and made things run 200 degrees cooler, you can bet you *** they'd be using them. What's more is you used to see them on race cars all the time 20 years ago--but not now. What changed? The dynamics of a drilled rotor? Or the understanding of how they work? I submit the understanding got better. The only think drilled rotors offer is an increase in surface area of the rotor. The trade off is less swept area for the pad to contact, and less smooth movement of the airflow through the cooling vanes (the holes create turbulence in the vanes).

 

I know what you are saying you are right any good salesman will talk up his product that is true. I just think there is both a lot of true and false information about brakes. I also understand and respect supporting the product you believe in, I do the same. And it is bad business not to offer the consumer what they want we do agree on that. I support drilled rotors based on independent data from a company called Link testing that we had many different brake combos tested at. I also run Drilled rotors on my daily driver, and so do many people that I know with out ever having a cracking issue. I understand it is becoming less common in racing (I too also only run slotted rotors on my track car) I just do not agree with many of the arguments against them. like the less swept area you speak of it is on average less than 3% of the contact surface lost under the friction material at any given time, this 3% is more than offset by the increase in airflow when braking at higher speeds. Slotted rotors usually loose up to 5% contact surface and have never been proven in any study to provide any real gain other than inreased pad bite, and this is at the sacrifice of pad life. I fully respect your views and don't want you to think that i am trying to beat on you with this, but it is a topic with much debate in the automotive industry. I will see if i can find the test data I had, If i can i will gladly post it up here. I for one enjoy discussing topics like this and hearing the different opinions. In all reality your brake setup just like suspension and drive train setup will all come down to personal preference and what you like and think works best. The way the car is built after all is no more than a reflection of it's driver.

 

If drilled rotors are so bad they why is GM using them on the z51 vetts and even the Zr1 ceramic discs are drilled.

 

A better question is: why don't they use them on their racing Corvettes?

 

Look at those beefy *** rotors... not something you would see on the street. I'm sure that Vette's braking forces would generate enough heat to outweight the benefits of BOTH a slotted or cross drilled rotor. No one ever said the drilled rotors were for racing only... we are debating the benefits of them in general, especially on the street.

 

brembo blanks are the way to go

 

These theory behind why is kinda in this thread and the links posted in this thread. You gotta kinda read the whole thing.

 

If you all want drilled rotors, I can sell drilled rotors. Brembo, PowerStop being two brands. I don't have them on my website because I don't believe in them. It's not a matter of my recommending what I have because I can't do something else. Anyone who'd like a quote on Brembo or PowerSlot drilled rotors, just let me know.

 

From my years of road track experience I have personally seen people crack drilled and slotted rotors. I have not seen any issues with slotted rotors. It all truly depends on how much track time you put into them. Drilled and Slotted are likely to break if road track racing all the time. Its like anything else. Take a piece of metal and try to bend it. Then take the same piece of metal and drill a bunch of holes in it. The one with holes is going to bend a lot easier because there is less material.

Its one thing to hear people bench talk about which is better but when you physically see a drilled and slotted rotor crack after severe road track abuse, it kinda answers the question. Maybe it was a coincidence or a poor rotor but I have been told for years not to used drilled and slotted if road track racing. Rotor thickness also plays a huge part. Some of the cars that come with drilled and slotted are not expected to truly see a ton of abuse. So they are fine for stock cars and regular driving abuse.

From my experience slotted is the way to go or smooth if you road track race on a regular basis.

 

Precisely.

Modern pads do not outgas; none of this is necessary. It only weakens the rotor. Go blanks or ATE slotted only. Avoid drilled at all costs.

Funny to see how many people voting drilled+slotted in the poll. Dear all of you: please never give brake advice again.