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Grooved / Drilled Disc Orientation

2003 - 2009, roadster, coupe, facelift
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Which direction?

Sweep direction anticlockwise (AP RACING)
7
50%
Sweep direction clockwise (PORSCHE)
7
50%
 
Total votes: 14

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kis
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Grooved / Drilled Disc Orientation

Post by kis » Thu Oct 19, 2017 3:12 pm

Okay so as above, after peoples opinion on grooved or drilled disc orientation (obviously includes dimpled discs too). This is also only for discs that are straight vented. Some vents travel in a specific manor to increase airflow and this can only be installed in one direction. However the majority of discs are grooved/drilled and have no specific vent direction... so after opinions or just response via poll. I'm saying this because typically you have a brake caliper set up at the "front" of the car... the Zed has the caliper sat towards the "back". Cheers guys :thumbsup:

Front of the car ---->
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Pic of john-z4's car... just a random shot I found!

ANTICLOCKWISE DIRECTION --------------------------------------- CLOCKWISE DIRECTION
(starting at the centre and moving outwards)
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My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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dhobbs
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Grooved / Drilled Disc Orientation

Post by dhobbs » Thu Oct 19, 2017 3:37 pm

What is the exact purpose of drilled/groved discs?
Is it to clear the brake dust and any hot gases produced under heavy braking? If so, then I will go with the picture on the left.
3.0si roadster. Requisite stubby. Sound gen mod. LED numberplate lights. LED boot strip. Interior lights LED too. ZHP gearknob. Daily drive :driving:
Motor in boot. Bilstein B8 dampers. New radio, much better sounds :thumbsup:

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ph001
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Grooved / Drilled Disc Orientation

Post by ph001 » Thu Oct 19, 2017 4:31 pm

Yes, pad gassing primarily. I'm not sure it makes a lot of difference which way the grooves run but the generally excepted way is for the groove to hit the pad on the inner radius first, so assuming the caliper is at the front of the car on your pics, the right one is correct.

Saying that, a great many brake discs are not sided so the left runs the opposite way to the right.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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bradz
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Grooved / Drilled Disc Orientation

Post by bradz » Thu Oct 19, 2017 6:00 pm

Isn't it more important that the scoops within the disc are dissipating the heat?
Z4M Coupe, E92 M3, E46 M3 Track car :driving:

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Grooved / Drilled Disc Orientation

Post by ph001 » Thu Oct 19, 2017 6:07 pm

bradz wrote: Thu Oct 19, 2017 6:00 pm Isn't it more important that the scoops within the disc are dissipating the heat?
Yep, that's the only thing that I would consider important.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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Steve84N
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Grooved / Drilled Disc Orientation

Post by Steve84N » Thu Oct 19, 2017 6:52 pm

Some discs tell you to put them on one way and some the other so it can't matter too much. The inner vanes are more important as you say. Many race cars run them with what seem to be the grooves running the 'wrong way'.

Drilled have just as many problems as benefits with cracking around the holes. It's as much about looks as anything as pad gasses aren't the problem they once were.

Grooves help keep the pad surface fresh and consequently wear pads faster.

Race cars run plain or grooved on the whole. Heat capacity is better with plain but it's marginal as not much is carved out. The holes/grooves aren't for cooling, the inner vanes are though.
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kis
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Grooved / Drilled Disc Orientation

Post by kis » Sat Oct 21, 2017 3:08 pm

50:50 ! Anyone else?
My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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Buckz
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Grooved / Drilled Disc Orientation

Post by Buckz » Sat Oct 21, 2017 4:08 pm

I'd put them the "correct" way round simply due to OCD. I can't think of any technical reason.

IMO only the center vents are important.
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kis
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Grooved / Drilled Disc Orientation

Post by kis » Sun Oct 22, 2017 4:40 pm

I know what you mean but there's no strict right or wrong way. But according to the stats 50% will think they're on correctly, with the other 50% thinking what a douche, he's got them on the wrong way round! I was hoping for something like 70:30 split to help me decide!
My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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Grooved / Drilled Disc Orientation

Post by Monkeydonkeyratmagic » Mon Oct 23, 2017 9:36 am

Directional with the wheel, reason being.

Less noise, grooved discs can be too noisy and sound corroded. More noise = More energy wasted = less efficiency = more prone to that lovely crack these things produce.

Imo anyway, Never had any joy with grooved and drilled discs.
MR-2 Turbo Rev2

Yep no Z yet. On the hunt.

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TomK
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Grooved / Drilled Disc Orientation

Post by TomK » Mon Oct 23, 2017 10:06 am

I just mount mine as AP say to do
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MC[IB], CSL airbox, Schrick 288/280 cams, 4.44FD, UUC SSK, SS race cat back, AP CP9660[F]/5144[R] brakes, Apex ARC-8 with AR-1 or PS5, KW ClubSport 2-way, Turner spherical arms, PMC uniball rtab, VB engine mounts, Rogue pulleys & RSMs, Tillett B6, half cage

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