BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Suspension | Brakes | Chassis
 
Post Reply
 
Thread Tools Search this Thread
      10-15-2012, 01:04 PM   #1
paradocs98
Major
 
paradocs98's Avatar
 
Drives: 2014 991 Carrera S
Join Date: May 2009
Location: NY

Posts: 1,342
iTrader: (0)

RS5 scalloped rotors?

Not sure if this has been discussed here before. I was at a car show yesterday and noticed that the new Audi RS5 on display had scalloped brake discs. The Audi rep couldn't tell me what the function of the scallops was. Anyone seen this or have an idea of what it's all about? I'm assuming if it was really functional, Brembo/StopTech/Alcon/AP would be doing it as well...
Attached Images
 
__________________
IB E90 M3 ZCP returned to BMW FS
paradocs98 is offline   United_States
0
Reply With Quote
      10-15-2012, 01:07 PM   #2
DominionXX
Private
 
Drives: M3 E92 Alpine White Coupe
Join Date: Aug 2012
Location: Richmond, TX

Posts: 80
iTrader: (0)

It is to shave weight/mass off each wheel. Not sure what the weight savings are??
DominionXX is offline   United_States
0
Reply With Quote
      10-15-2012, 01:29 PM   #3
808MGuy
Colonel
 
808MGuy's Avatar
 
Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

Posts: 2,259
iTrader: (3)

2nd. From what I've read it was an attempt to shave some excess weight. Also, no car manufacturer makes their own brakes so there is a chance that one of those companies you mentioned OEM'd those rotors for Audi.
__________________
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE

808MGuy is offline  
0
Reply With Quote
      10-15-2012, 01:48 PM   #4
DB
e90m3/e92 335xi
 
DB's Avatar
 
Drives: e90 m3
Join Date: Mar 2010
Location: Philly

Posts: 109
iTrader: (0)

Saves more than 2lbs per corner according to Car and Driver:

"The clever Quattro Volk carve out portions of each rotor’s periphery and call them 'wave rotors,' claiming that they cumulatively reduce unsprung and rotating mass by nine pounds."
DB is offline   United_States
0
Reply With Quote
      10-15-2012, 02:47 PM   #5
paradocs98
Major
 
paradocs98's Avatar
 
Drives: 2014 991 Carrera S
Join Date: May 2009
Location: NY

Posts: 1,342
iTrader: (0)

Quote:
Originally Posted by DominionXX View Post
It is to shave weight/mass off each wheel. Not sure what the weight savings are??
Quote:
Originally Posted by 808MGuy View Post
2nd. From what I've read it was an attempt to shave some excess weight. Also, no car manufacturer makes their own brakes so there is a chance that one of those companies you mentioned OEM'd those rotors for Audi.
Quote:
Originally Posted by DB View Post
Saves more than 2lbs per corner according to Car and Driver:

"The clever Quattro Volk carve out portions of each rotorís periphery and call them 'wave rotors,' claiming that they cumulatively reduce unsprung and rotating mass by nine pounds."
Got it. Thanks. Makes sense, except in the context of a 4000lb coupe riding on big 20" wheels and tires. "M stands for Marketing" could apply to Audi as well, I suppose...
__________________
IB E90 M3 ZCP returned to BMW FS
paradocs98 is offline   United_States
0
Reply With Quote
      10-15-2012, 04:09 PM   #6
r1concepts
First Lieutenant
 
Drives: 07' E90 335i
Join Date: Jul 2009
Location: La Habra

Posts: 357
iTrader: (2)

I believe Wilwood makes these type of rotors.
r1concepts is offline   United_States
0
Reply With Quote
      10-15-2012, 04:35 PM   #7
Sully1Time
Second Lieutenant
 
Drives: 09' Alpine White M3
Join Date: Aug 2012
Location: SoCal

Posts: 200
iTrader: (6)

Garage List
2009 BMW M3  [5.00]
This type of rotors have been available for sport bikes for years. I'm actually surprised it took the auto industry this long to manufacture rotors this way. And as others have stated, it's for weight reduction. I also believe its mostly marketing hype, as none of the race bikes run wave rotors.

I have 2 bikes both with wave rotors since 07'

97 Suzuki TLS1000





07 Suzuki GSXR1000



__________________
09' AW M3, 6MT, Black Novillo Extended, Carbon leather trim, Premium, Moonroof, OEM Carbon spoiler, BMW LED Int. Bulbs, Avant Garde 19x11/19x9.5 M310 wheels, OOLux V3 AEOO, Vorsteiner Type II diffuser, Megan Racing Stainless exhaust, Benvo Stage 1 tune, Dinan High Flow Carbon Fiber Intake, Dinan Front anti-sway bar, H&R Sport springs, 30% tint

Last edited by Sully1Time; 10-15-2012 at 05:02 PM.
Sully1Time is offline  
0
Reply With Quote
      10-15-2012, 05:32 PM   #8
Porschefile
Major
 
Porschefile's Avatar
 
Drives: E92 M3
Join Date: Jul 2008
Location: Tennessee

Posts: 1,222
iTrader: (6)

There's a reason DP's and other high end racing cars don't run these. The scalloping saves weight, but it also lowers surface area of the rotor. Drilled rotors are lighter than slotted (generally) but racers all know that slotted is better for the track.

Good call on the "Marketing" reasoning above. Our cars have 2 piece rotors for show that are inefficient and use a mounting design that blocks half of the air flow rather than using a well designed and more efficient 1 piece so BMW can say we have "2 piece drilled rotors!". Stoptech rotors are a lot less expensive than OEM and work much better too.
Porschefile is offline  
0
Reply With Quote
      10-15-2012, 05:48 PM   #9
808MGuy
Colonel
 
808MGuy's Avatar
 
Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

Posts: 2,259
iTrader: (3)

Quote:
Originally Posted by Porschefile View Post
There's a reason DP's and other high end racing cars don't run these. The scalloping saves weight, but it also lowers surface area of the rotor. Drilled rotors are lighter than slotted (generally) but racers all know that slotted is better for the track.

Good call on the "Marketing" reasoning above. Our cars have 2 piece rotors for show that are inefficient and use a mounting design that blocks half of the air flow rather than using a well designed and more efficient 1 piece so BMW can say we have "2 piece drilled rotors!". Stoptech rotors are a lot less expensive than OEM and work much better too.
Don't most high end racing teams run solid rotors for maximum heat transfer? I don't think Audi is marketing these cars for use on the track in stock form. The RS5 is actually intended to be a GT car if I'm not mistaken. Even BMW doesn't come out and say run your M3 hard on the track with stock components. Anyone who is serious about the track would have dedicated track rotors and pads at the least.
__________________
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE

808MGuy is offline  
0
Reply With Quote
      10-15-2012, 05:53 PM   #10
Porschefile
Major
 
Porschefile's Avatar
 
Drives: E92 M3
Join Date: Jul 2008
Location: Tennessee

Posts: 1,222
iTrader: (6)

Quote:
Originally Posted by 808MGuy View Post
Don't most high end racing teams run solid rotors for maximum heat transfer? I don't think Audi is marketing these cars for use on the track in stock form. The RS5 is actually intended to be a GT car if I'm not mistaken. Even BMW doesn't come out and say run your M3 hard on the track with stock components. Anyone who is serious about the track would have dedicated track rotors and pads at the least.
Most high end racecars run J hook or slotted iron rotors I believe. I think carbon rotors are typically (maybe exclusively) solid. I don't agree on the marketing it for x purpose argument. If they care about the few pounds of weight then they should care about heat transfer. Nobody care about how much their rotors weigh on the way to work.
Porschefile is offline  
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 11:26 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST