Cross drilled rotors pattern suggestions

MMamdouh · Post by **MMamdouh** » Fri May 20, 2005 10:03 pm

i am thinking of cross drilling my OEM rotors but i am not sure which port pattern to go with, i have the 12" rotors and 32 ventlation ducts in it and i have tried some patterns but those two are the best i got:

this is a 16 arc pattern where each arc is formed of 3 ports, this will make the rotor much lighter i guess due to the numerous ports drilled in it but i am afraid the "too many" ports will make the rotor weaker... i am sure it will make the braking performance better and brakes heat much less but is it safe??

this is an 8 arc pattern where each arc is formed of 4 ports, this will be easy to do as their is not many holes on it and the rotor will still be strong structured... what about effecency?? will the 32 ports supply enough ventlation and cooling to make any difference? in other words are the performance gains worth the effort??

i also need info on ports size and all... i don't know how big they are supposed to be or if their is any thing special should be done during the process, any feedback is highly appreciated.

i know some people might say that porting the OEM rotors are not worth it but we don't have here aftermarket cross drilled rotors and that job will be a trial for drilling my current brembo rotors.

P.S: sorry the pics doesn't look that great but they look much better in thumbnail mode at the tech. images in the album section.

MMamdouh

mocpac · Post by **mocpac** » Fri May 20, 2005 10:19 pm

some guy on ebay is selling cross drilled rotors check it.

BosnianLanos · Post by **BosnianLanos** » Sat May 21, 2005 12:01 am

If you guys don't have Drilled/Slotted rotors in Egypt, this idea has some possibility. Drilling will not make a huge improvement for weight as most of the weight is held in the inner fins and hub which you can't drill and a few 1/8 inch holes won't do a great deal for weight. As for braking, I also don't think that the improvement would be huge. Manufacturers are adding slotting to the brake pads themselves which acts like a slot on a rotor but is much safer (I think your brakes have them from your earlier post). As for safety, I wouldn't do it. The holes will definately decrease the rigidity of the rotor and due to the quick Heating/Cooling process of the holes, the rotor would be more likely to develop a crack at the holes. Since drilling through the rotor would reveal bare metal underneath with no coating, rust may become an issue, further weakening the rotors. Another major issue is that if the rotor is not well balanced, the gyroscope motion might cause steering shake and caliper damage. You would need good measurements and someone skilled on a very strong drill press.

As far as Drilled/Slotted rotors go, they are more for show then for go, it is a comman misconception that if rotors are drilled the braking will be better. Brakes work better if they are warmed up. Most companies and cars, including the WRX STi, Lancer Evolution, and SLR Mercedes-Mclaren (vented ceramic) all have regular rotors, not for price, but for function.

It is all up to you though, there is an option to buy simply slotted rotors from an Australian company that made the rotors for the Supercharged Lanos Howler, I was quoted less than $300 for both rotors and shipping from their warehouse in California. I forget the name but I could look it up.

kinkyllama · Post by **kinkyllama** » Sat May 21, 2005 12:05 am

BosnianLanos wrote: As far as Drilled/Slotted rotors go, they are more for show then for go, it is a comman misconception that if rotors are drilled the braking will be better. Brakes work better if they are warmed up. Most companies and cars, including the WRX STi, Lancer Evolution, and SLR Mercedes-Mclaren (vented ceramic) all have regular rotors, not for price, but for function.

I hear people say that all the time but my slotted rotors made a HUGE difference. At high speeds it probably cut my braking time in half.. not to mention less brake "fade"

lanos2001 · Post by **lanos2001** » Sat May 21, 2005 12:12 am

I hear people say that all the time but my slotted rotors made a HUGE difference. At high speeds it probably cut my braking time in half.. not to mention less brake "fade"

it does make you stop quicker or people wouldn't have them. but making the brakes fade less is not true unless you go with aftermarket pads like you already have. but since its slotted and drilled or just one of the two it actually eats away at the brakes a bit more. its like a razor taking off peices at a time instead of just rubbing off. but it would just be a minimal difference in wear a tear.

nick

Brian5475E · Post by **Brian5475E** » Sat May 21, 2005 12:18 am

Need to watch what you are doing. Cross drilled rotors go trough special processes so they don't shatter.

DomWoo · Post by **DomWoo** » Sat May 21, 2005 2:46 am

slotted and drilled rotors do the opposite of what most people think, its not there to help stop. slots allow gases to leave the pads and the drill holes make the pads heat up quicker

they will actaully get hotter then regular rotors in less time. i can tell you one thing. my 12" rotors make a HUGE difference and they are drilled and slotted

kinkyllama · Post by **kinkyllama** » Sat May 21, 2005 3:02 am

WooHoo wrote:slotted and drilled rotors do the opposite of what most people think, its not there to help stop. slots allow gases to leave the pads and the drill holes make the pads heat up quicker

I know.. thats why i said there is less brake fad and better braking from high speeds. But still even from lower speeds.

MMamdouh · Post by **MMamdouh** » Sat May 21, 2005 2:39 pm

so in general you are saying not to do this... it will not add that much performance, will be hard to do and on top of all won't be safe.

the cross drilling project gone bye bye.

MMamdouh

Audacity Racing · Post by **Audacity Racing** » Sat May 21, 2005 8:17 pm

do NOT drill your rotors...

the steal has been heat treated before if was put on your car. if you drill the heat treated steel and create hot spots, you will weaken the steel at those points. turning a rotor is ok because the heat is uniform across both sides of disk as it turns.

you WILL ruin your brakes by drilling them... i wouldn't ride in a car going over 60 mph (100kph) with drilled brakes that were NOT meant to be

debo890 · Post by **debo890** » Sun May 22, 2005 9:08 am

WooHoo wrote:slotted and drilled rotors do the opposite of what most people think, its not there to help stop. slots allow gases to leave the pads and the drill holes make the pads heat up quicker

they will actaully get hotter then regular rotors in less time. i can tell you one thing. my 12" rotors make a HUGE difference and they are drilled and slotted

not totally true. sorry woohoo

slots are there to scrap the glaze off the pad so that there is fresh material to use for braking. they also help vent off gas build up. drilled holes are there to let gas escape during the heating of the pad and also cool the rotor.

MMamdouh · Post by **MMamdouh** » Sun May 22, 2005 11:33 am

debo890 wrote:
WooHoo wrote:slotted and drilled rotors do the opposite of what most people think, its not there to help stop. slots allow gases to leave the pads and the drill holes make the pads heat up quicker

they will actaully get hotter then regular rotors in less time. i can tell you one thing. my 12" rotors make a HUGE difference and they are drilled and slotted
not totally true. sorry woohoo
slots are there to scrap the glaze off the pad so that there is fresh material to use for braking. they also help vent off gas build up. drilled holes are there to let gas escape during the heating of the pad and also cool the rotor.

i was going like

how can drilled holes make a rotor hotter?? but i didn't give it much thought 'cause i gave up on the project anyways.

MMamdouh