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drilling rotors for venting?


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17 replies to this topic

#1 archemitis

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Posted 20 September 2003 - 12:31 PM

i am going to pick up a set of new rotors for my hatch, but before i put them in i am going to stick them on the brigeport and cross drill the hell out of them. they are solid, and im hoping this will keep them from warping again. does anybody have any reason this would be bad? sould i have them turned afterwards?

#2 baccaruda

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Posted 20 September 2003 - 12:36 PM

uhh, don't, actually.. I have a guy in Spokane that I need to get some subaru info to.. and he takes lots of meaurements and plots the drilling pattern on autoCAD to avoid the vanes in the middle and such. It could affect the balance and cause heating or warping, I'd think. Good idea though..

#3 archemitis

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Posted 20 September 2003 - 12:40 PM

i dont think mine have the vents/vanes in the middle. they are just like a big thick motorcycle disc
i suppose i could check the balance, oldschool style

#4 Hodaka Rider

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Posted 20 September 2003 - 02:45 PM

Drilling actually makes them more susceptable to warping and cracking in street use. If you plan on off-roading it could be even worse. Call Skip and see if he's hooked up for brakes yet. Ask for slotted rotors.

#5 Setright

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Posted 20 September 2003 - 03:33 PM

DON'T DRILL THEM!! You will weaken the disc considerably.

I know Porsche and Mercedes are now producing road cars with drilled discs, but a lot of engineering expertise has gone into determining the placing, diameter, and number of holes.

You can drill "blind" holes, ie. not all the way through the disc, if holes are what you want.

Slots are a far better option, and you only really need four slots per side - any extras are just for show and eat the pads really fast.

Speaking of which, what pads are you using? Many cases of brake judder stem from overheated pads that deposit material randomly on the disc surface, not "warped" discs.

I strongly recommend Mintex "Red Box" pads. They aren't the best in terms of ultimate power, but they stand up to considerable torture without breaking down and can be used daily.

#6 Hodaka Rider

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Posted 20 September 2003 - 04:26 PM

Generally, OEM rotors have the holes cast in place and chamfered.

#7 archemitis

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Posted 20 September 2003 - 05:02 PM

that doesnt sound right... i think im gonna give it a try, they are $15 dollars a piece. whats the worse that can happen? they will warp agian?

#8 Hodaka Rider

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Posted 20 September 2003 - 05:08 PM

Either that or crack and possibly shatter. No biggie, I guess.

#9 JWX

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Posted 20 September 2003 - 07:36 PM

I say try it. its your car and your money I also want too now how they work :headbang:

#10 MorganM

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Posted 22 September 2003 - 10:26 PM

Ive seen shatterd rotors on a friends car. It didnt look like anythying I wanted to experience...

#11 Hodaka Rider

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Posted 22 September 2003 - 10:38 PM

My feeling exactly first time I saw 'em.

#12 GLCraig

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Posted 22 September 2003 - 10:40 PM

One problem you'll run into when drilling the rotors is the fact that you will be decreasing the mass of the rotor. Decreasing the mass will make them more susceptible to warping. You would be best off having them cryogenically treated.

Legacy777 on the new generation board is has done some research on this topic, you may want to email him to get more info.

#13 Guest_taprackready_*

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Posted 23 September 2003 - 12:31 AM

If you adjust the rear brakes properly it helps a great deal in preventing front brake warpage. Most people don't adjust the rears and will replace front pads 3, 4 times before the rears even start to wear out.

Just a thought

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#14 dsmracer

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Posted 23 September 2003 - 01:03 AM

Originally posted by archemitis
that doesnt sound right... i think im gonna give it a try, they are $15 dollars a piece. whats the worse that can happen? they will warp agian?



The worst that can happen is they will explode under hard braking. Maybe even causing an accident. Cross drilling OEM discs lessens the available suface area, effectively lengthening your stopping distances. Most full blow race cars like those in the JGTC even have only slotted rotors now.

Your best bet is to get some Brembo OE replacements. Brembo uses superior alloy to begin with. If warpage is your main motivation, take $100 bucks and have them cryo treated. This does wonders for fade resistance and warping. Check out Cryo Science for more info.

#15 NickNakorn

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Posted 25 March 2013 - 08:47 PM

made a comment - realised this was 10 years old and now cant delete the comment - only edit it - how do I delete a comment?


Edited by NickNakorn, 25 March 2013 - 09:03 PM.


#16 nipper

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Posted 25 March 2013 - 10:00 PM

that doesnt sound right... i think im gonna give it a try, they are $15 dollars a piece. whats the worse that can happen? they will warp agian?

They can shatter and you can kill someone...



#17 nipper

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Posted 25 March 2013 - 10:01 PM

made a comment - realised this was 10 years old and now cant delete the comment - only edit it - how do I delete a comment?

So your the reason i replied to this .. bad bad no subaru for you.



#18 spazomatic

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Posted 27 March 2013 - 12:24 AM

Wow glad you said something, I was about to chime in on it.

For future reference, drilling rotors yourself is a bad idea.

....looks like i chimed in anyway

Edited by spazomatic, 27 March 2013 - 12:29 AM.





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