Author Topic: question on X drilled & slotted rotors  (Read 2481 times)

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bog4rt

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question on X drilled & slotted rotors
« on: September 03, 2007, 09:31:12 PM »
i installed rotors and new pads on my A4 a while back. when i got the rotors, only the back ones were labels R or L. so i matched the directions the slots and drilled holes were going and put them on that way. i get a noise that sounds like clicking as i drive my car, and when i apply pressure on the brake pedel this click noise intensifies. i know it is from my rotors or pads. question is why?  i dont think there warped because i dont have any steering vibrations or shaking when i brake(even at high speeds when i press them hard to slow down quickly, no vibrations) so if anyone has some insights on this i would apprecaite it.  rotors were zimmerman i believe and the pads where just semi-metallic ones from autozone.

03Indigo

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Re: question on X drilled & slotted rotors
« Reply #1 on: September 03, 2007, 09:33:57 PM »
it is the pad hitting the slots.  Mine make a small amount of noise, clicking, and also a whirring when they go over the drilled holes.  So, I click and whir.  Higher performance brakes will cause more noise, clicks, whirs, and even squeaking due to temperature ratings.

I use ceramic pads, they seem to cut down on the noise, and provide better street performance...but not ideal for track.

Rocky Mountain Club B5

Re: question on X drilled & slotted rotors
« Reply #1 on: September 03, 2007, 09:33:57 PM »

ColoradoB5

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Re: question on X drilled & slotted rotors
« Reply #2 on: September 04, 2007, 01:36:08 AM »
Yep, mine do the same thing.  Here's what they look like mounted without the wheels, so you can check on the direction.



Forward is to the left.
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Eric18T

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Re: question on X drilled & slotted rotors
« Reply #3 on: September 04, 2007, 02:14:48 AM »
mine don't make any clicking or whirling.  i have heard that many slotted rotors make whirling sounds when braking. my vanes face the opposite most though since the the internal vane direction is key (oposing internal vane direction from slotting). Maybe since mine face the opposite direction that keeps the whirling to the minimum.

Since most OEM type rotors are straight vaned i wonder if the whirling would stop of you flipped them around to have the slots face the direction of mine?  You won't be changing the cooling properties since the internal vanes are straight in most cases.

« Last Edit: September 04, 2007, 02:17:49 AM by Eric18T »

gragravar

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Re: question on X drilled & slotted rotors
« Reply #4 on: September 04, 2007, 02:21:00 AM »
I have the funky little stasis dimples



and even they make a funky whirring sound under heavy braking.
Any man who can drive safely while kissing a pretty girl is simply not giving the kiss the attention it deserves.  ~Albert Einstein

90Carat

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Re: question on X drilled & slotted rotors
« Reply #5 on: September 04, 2007, 03:00:25 PM »
Yep, mine do the same thing.  Here's what they look like mounted without the wheels, so you can check on the direction.



Forward is to the left.

SP Performance rotors?  If so, how do you like them?  I am about to order up a set..
have a 92 S4, and old Porsche, and some Japanese stuff sittin' in the garage.

ColoradoB5

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Re: question on X drilled & slotted rotors
« Reply #6 on: September 04, 2007, 03:36:05 PM »
They are Brembo Rotors actually.  I bought them 3 years ago at ECSTuning.com.

I do like them.  They have held up well.  All that's left now though is the cross drill holes, since the slots have worn down with the rotor.  I'll be switching them out again next spring.  I will probably go with the same thing.
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jayryan

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Re: question on X drilled & slotted rotors
« Reply #7 on: September 04, 2007, 09:14:58 PM »
I'm ordering up a set tomorrow. So Eric are you saying run them opposite? Interesting.
'03 A4 1.8TQM
'68 MG C
'06 4Runner

Eric18T

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Re: question on X drilled & slotted rotors
« Reply #8 on: September 04, 2007, 10:19:39 PM »
I'm ordering up a set tomorrow. So Eric are you saying run them opposite? Interesting.

I think it is worth a try. Obviously you need to make sure the internal vane direction is correct. but if they are straight vaned (most) i think it is worth a try. I have not heard any whirling sounds and the dust/water sweep off my rotors just fine. worse comes to worse you can always swap 'em later.

ColoradoB5

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Re: question on X drilled & slotted rotors
« Reply #9 on: September 05, 2007, 01:43:47 PM »
JR, if you have any doubts, ask the folks at ECS Tuning which way they should go.  They should know.
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DenverPat

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Re: question on X drilled & slotted rotors
« Reply #10 on: September 05, 2007, 02:14:38 PM »
Slot direction is not as important as the vanes inside the rotor.  Base the orientation on the vanes.
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ColoradoB5

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Re: question on X drilled & slotted rotors
« Reply #11 on: September 05, 2007, 06:33:00 PM »
Pat, you're so vane.
You can't rehabilitate a fire ant.

jayryan

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Re: question on X drilled & slotted rotors
« Reply #12 on: September 05, 2007, 08:49:59 PM »
:D My rotors are a-ok. So it's just pads for now.
'03 A4 1.8TQM
'68 MG C
'06 4Runner

ColoradoB5

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Re: question on X drilled & slotted rotors
« Reply #13 on: September 06, 2007, 02:20:57 AM »
What pads are you going with?  I have been happy with my PBRs.  Of course they did better on the first set with new rotors than the second set on the same rotors. 
You can't rehabilitate a fire ant.

Kraylon

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Re: question on X drilled & slotted rotors
« Reply #14 on: September 06, 2007, 12:09:43 PM »
i have the same setup as coloradb5 with ebc's redstuff pads (great combo) and they make a little bit of clicking it kinda sounds like a cricket out in the distance

bog4rt

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Re: question on X drilled & slotted rotors
« Reply #15 on: September 07, 2007, 05:59:46 PM »
thats the exact noise i am getting. so... good news then its normal sound

jayryan

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Re: question on X drilled & slotted rotors
« Reply #16 on: September 07, 2007, 10:37:25 PM »
What pads are you going with?  I have been happy with my PBRs.  Of course they did better on the first set with new rotors than the second set on the same rotors. 

PBR Ceramics I expect. But the title the DMV got for my car doesn't have my name on it so my bank's like "wtf mate?" It looks like they need to get a new one from Cali with the proper name...probably take 6-7 weeks so I'm just going to sit on the pad order for now.

...and if I wait just two more months, I can cut my licensing fee in half ::)
« Last Edit: September 07, 2007, 10:42:41 PM by jayryan »
'03 A4 1.8TQM
'68 MG C
'06 4Runner