E46Fanatics - View Single Post - I need ROTORS: Slotted vs. Drilled vs. OEM ?????
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Old 03-01-2007, 04:54 AM   #1
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I need ROTORS: Slotted vs. Drilled vs. OEM ?????

Ok so it is time to get new rotors/pads and I have been researching what to purchase. I have read through quite a number of threads here but have yet to come to a conclusion. What exactly are the benefits of slotted or drilled rotors compared to OEM? Here are a couple tidbits of info I came across while searching:

Directly off of UUC's website...
"Slotting: there are many reasons to slot rotors. Primarily, slotting aids in removal of water and debris on the rotor surface, evacuation of hot pad "off gassing" vapor, and provides a visual wear indicator.

Details: These slots do not extend all the way to the edge of the rotor for a very specific reason; this maintains the structural integrity of the rotor. Other brands with slots all the way to the end have created "stress risers" where cracking may develop. No such problem exists with this design. Additionally, directional slotting enhances effectiveness.

NO DRILLING! Drilled holes in rotors often used for "show" are prone to cracking and catastrophic failure. The holes create stress risers which will lead to this sort of failure. Additionally, drilled holes do not improve cooling, rotary-vane rotors lose efficiency when drilled because cooling air does not not pass through the rotor circumferentially but is instead prematurely evacuated by the holes.. "

Hmmm if cross drilled rotors do no improve cooling and are prone to failure then why would any BBK use them?

Also here is more info found when scanning ebay (link below)...
"Brembo OE "blank" rotors offer better performance than Cross-drilled rotors. Cross-drilled rotors might look "cool", but what are they really doing for performance? Brake rotors were first "drilled" in the 40's and 50's because early brake pad materials gave off gasses when heated to racing temperatures, which is called "gassing out". These gasses then formed a thin layer between the brake pad face and the rotor, effectively lowering the coefficient of friction. The "cross drilled" holes were implemented to give the gasses a place to escape. Today's brake pad materials do not exhibit the same gassing out problems as these early (old) pads. Also, there are many companies that sell "cheap" cross-drilled and slotted rotors. They do this by purchasing Brembo blanks and having them cheaply altered by a third party. Doing this sacrifices the rotors structural integrity, and can be a huge safety risk. If you contact Brembo, they will not recognize these discs after they have been altered. These rotors are known to crack and warp very quickly. If you want the actual Brembo cross drilled and slotted rotors you will be paying much more. That's why these blanks are perfect; they perform better, do not tear through pads, are priced much lower, and are much safer."

So right now I am deciding between the following rotors:

1. Stoptech Cross Drilled Rotors

2. Stoptech Slotted Rotors

3. Cross Drilled Brembos (stated above are most likely punched by a 3rd party)

4. UUC Slotted Rotors

5. OEM Rotors

I really like the look of the cross drilled rotors but do not want to purchase them at the risk of performance and safety. Hopefully someone can enlighten me. Rob maybe? Thanks in advance

Last edited by freshprince2421; 03-01-2007 at 05:48 AM.
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