how many vents in a Cobra rotor???

[bryan0]

How many vents are in a 13" Cobra front rotor?

please either tell me if you're talking about how many metal "fins" or how many spaces.

My father runs a machine shop (kind of) and I've ordered the cobra rotors. I was thinking about drawing a model of the drill pattern i want on CAD and having it CNC'd onto my rotor. Then maybe get it gold cadmium plated.

I'm not going to do it unless I'm 100% sure I know what I'm getting myself into, but he said he could do it and that I should "trust him" lol. I'd like to know the # of vents so I can draw the rotor on cad.

Any thoughts or suggestions about this? Thanks.

 

[Mustang5L5]

Self-drilling your own crossdrilled rotors can lead to many problems. Unless done correctly, drilling holes can stress the rotor in such a way that it will crack very easily.

Also, drilling the holes will decrease the mass of the rotor creating more heat which will lead back to problem number 1....cracking.

Any drilling of holes must be done with a liquid cooled drill on it's slowest speed. Heat generated must be kept to a minimum and you should chamfer the holes whel done to decrease stress slightly.

Good luck.

 

[Kilgore Trout]

Do not make your own rotors unless your father is a highly skilled machinist.

 

[03ghoststang]

i wouldnt recommend you drilling holes onto a rotor cause if done wrong by even the slightest margin = a big

 

[bryan0]

ok, thanks for the input, but does anyone know how many vents there are or where i could find that out?

 

[Mustang5L5]

Depends on what brand rotor you use.

Not all will be the same. The vents of the 94-98 Cobra rotors are not the same as the vents on the 99+ Brembo Cobra rotor. Aftermarket rotors are different as well. It's not exactly standardized. Some factory rotors may be vaned directionally while others are straight so you could use them on either side.

 

[Kilgore Trout]

Good rotors have the holes cast into them and are never drilled. Drilling leads to cracking as mentioned above.

 

[Mustang5L5]

Good rotors have the holes cast into them and are never drilled.

Actually many aftermarket companies and some reputable companies machine the drilled holes into their rotors after they are cast. Brembo does it as well. The difference is the better quality companies have more controlled environments when the rotors are drilled and do not alter the metal properties of the steel when it is done. Companies like Baer and Brembo have the benefit of testing their rotors to see if they have been compromised at all and can alter their machining methods. Also, the rotors must be balanced after the drilling...which isn't something easliy done. The reason drilled rotors tend to crack a lot is due to the drilling in areas which makes the rotor structurally weaker and heat generated during the drilling which makes the surrounding metal brittle and weaker. Pretty much ALL of the cheapo cross-drilled rotors on EBay are solid rotors that have been machined. There is even one company purchasing Brembo rotors and machining them themselves and selling them under the Brembo name.

Now while 99% of these rotors will generally never fail, i still wouldn't attempt it.

 

[Kilgore Trout]

Thanks for the info