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Grooved or Drilled

Discussion in 'A3/S3 Forum (8L Chassis)' started by imported_rashpal1, Sep 6, 2005.

  1. imported_rashpal1
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    imported_rashpal1 Guest

    [Sep 6, 2005]
    Hi Guys,

    Just a quick question..

    In you opinions which brake discs are better, Drilled or Grooved..

    Pal
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  3. evotista
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    evotista Member

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    [Sep 6, 2005]
    As always, a tough question....i think the majority of posters say that grooved is the safer bet, obviously less likely to crack....particularly if not cast in holes. People like Brembo bill will only sell grooved ones...so that says something about drilling......however others like PaulS3 or RichA3 are more than happy with their quality porsche/ ECS drilled setups.

    At the end of the day, i think that if going for "cheaper" disc setups (EBC, OE Equivs, even maybe Brembo GT jnr kit)...grooved is safer bet.....when you get in to major league Big Brake Kits (ECS 2v2 and above, Porsche Big Reds et, AP 4/6 pot)...i think drilled or drilled grooved are still a safe bet...given sufficient attention is given to cooling.

    but hey, what do i know.....i have yet to experience any of the above setups!..this is just my synopsis of 2 years of reading threads on here, TS and TT forums.

    I'm sure Ess or David R will be along soon to add their more experienced 2p!

    HTH
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  4. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Sep 6, 2005]
    My 'BREMBO' GT jnr kit came with drilled disks /ubbthreads/images/graemlins/smirk.gif

    And as you can see from my sig, they are warped! /ubbthreads/images/graemlins/frown.gif
    #3
  5. imported_rashpal1
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    imported_rashpal1 Guest

    [Sep 6, 2005]
    Hi Jojo

    How long have you had you Brembo kit for, and did your discs warp under normal / fast road use..

    I have my kit on order still, was supposed to have it weeks ago but the supplier has had stock problems. Should be shipping this Thusrday!!

    Was thinking if i should change to grooved ones instead..
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  6. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Sep 6, 2005]
    It was after a track session actually, but I didn't drive hard for more than 5 laps at a time, and took all precautions in cooling down with slow inlap, and parking up with handbrake off etc..., so pretty disappointed really. I've now got Leon Cupra R disks lined up, they are solid, and cost £100 less than the drilled items, but still darn expensive though. /ubbthreads/images/graemlins/smirk.gif
    Would go for an ECS2v2 kit if I had known it was available at the time.
    #5
  7. imported_rashpal1
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    imported_rashpal1 Guest

    [Sep 7, 2005]

    Great, i knew i should have ordered the grooved kit instead of the drilled one. Oh well i think it is too late to change the order now as they are finally getting shipped tomorrow. If i change the order now i prob have to wait another six weeks..

    Pal
    #6
  8. PaulRS3
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    PaulRS3 Well-Known Member

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    [Sep 7, 2005]
    its all in the castings


    ie cast in holes, not drilled. (oem porsche)


    saying that they still crack, just not as bad or as fast i believe.
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  9. DavidR
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    DavidR Active Member

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    [Sep 7, 2005]
    I've got the plain Cupra R discs under a Brembo caliper. The original drilled Brembo disc cracked badly around the holes. Thus far the plain disc works better in terms of performance and hasn't suffered any cracks.

    However, if you use brakes very harshly then they will all check, crack and ultimately fail - none are immune if used hard enough.

    I'm really pleased with the current combo of Brembo, plain disc and DS2500 pads - the best brakes I have used on any car. Saying that I use the car on track alot and the brakes very hard. It takes only a day or two of road driving to get the pads squeeling... but everything is a compromise.
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  10. evotista
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    evotista Member

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    [Sep 7, 2005]
    David,

    Can you explain why you get the squealing from road use?..,.is it because they're not working at optimum temperatures when doing "ordinary" driving?
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  11. DavidR
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    DavidR Active Member

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    [Sep 7, 2005]
    Presume it's something to do with that. AFAIK brakes work by friction (i.e. an abrasive surface on bare metal) or adhesion (brake pad on disc with pad material deposited).

    The former can lead to squeal and the latter for optimal braking.

    If you use a very aggressive pad hard and get it very hot you brake using the pad against a bonded layer of pad material on the disc. If you use the same pad cold (relatively) you scrub the disc clean (as no pad material transfer occurs when cold) and run with metal vs pad = squeak..

    Other causes are that the DS2500 are a race pad and therefore have no antisqueal shims and also are fractionally smaller (i'm told) than non race pads to allow for the extra heat expansion - a wobbly pad will resonate and squeal at low temps.
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  12. ianhg
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    ianhg Member

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    [Sep 7, 2005]
    [ QUOTE ]
    My 'BREMBO' GT jnr kit came with drilled disks /ubbthreads/images/graemlins/smirk.gif

    And as you can see from my sig, they are warped! /ubbthreads/images/graemlins/frown.gif

    [/ QUOTE ]

    my brembo discs were warped within the first few months of being on the car, they were replaced under warrenty with a nice new set of grooved ones /ubbthreads/images/graemlins/woohoo.gif
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  13. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Sep 7, 2005]
    Apparently, AmD have a few options with replacing disks on the Brembo GT jnr set-up, without going the expensive OE Brembo disks route, anyone called them up to enquire?
    #12
  14. The Slug
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    The Slug Active Member VCDS Map User

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    [Sep 7, 2005]
    Joe u still after replacements? anymore news on the FMIC
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  15. scoTTy
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    scoTTy Active Member

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    [Sep 7, 2005]
    I had these fitted to my S4 a week or two ago :
    [​IMG]

    I spoke to JBR (the ECS distributor) and although they'd not had any problems with drilled, the recommendation was still for grooved which matched my own thoughts.

    The big improvement so far has been the cars handling. They are 40% lighter than stock and the car is so much better for it. The air gap is twice the size of OEM and the venting vanes are scooped to grab more air. I'm very happy with them so far but the real test with be this weekend at the 'ring.
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  16. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    [Sep 7, 2005]
    [ QUOTE ]
    I had these fitted to my S4 a week or two ago :
    [​IMG]

    I spoke to JBR (the ECS distributor) and although they'd not had any problems with drilled, the recommendation was still for grooved which matched my own thoughts.

    The big improvement so far has been the cars handling. They are 40% lighter than stock and the car is so much better for it. The air gap is twice the size of OEM and the venting vanes are scooped to grab more air. I'm very happy with them so far but the real test with be this weekend at the 'ring.

    [/ QUOTE ]

    WOW, top stuff Scotty, have fun at the 'ring and keep us posted. /ubbthreads/images/graemlins/wink.gif
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  17. Ess_Three
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    Ess_Three Active Member

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    [Sep 8, 2005]
    [ QUOTE ]
    I had these fitted to my S4 a week or two ago :
    [​IMG]

    The big improvement so far has been the cars handling. They are 40% lighter than stock and the car is so much better for it.


    [/ QUOTE ]

    Valid point...but I have severe reservations about the use of multi-piece discs on road cars...many road cars are just not looked after well enough to ensure the rotors and hats remain free - assuming they are a floating disk?

    The problem us northern types have is that the salt on the road will have them beauties seized solid in a matter of weeks...leading to additional brake problems.


    [ QUOTE ]

    The air gap is twice the size of OEM and the venting vanes are scooped to grab more air.

    [/ QUOTE ]

    Or is it to throw more air out? /ubbthreads/images/graemlins/wink.gif

    Generally, vented discs work better when being force fed air..something Audi bumpers don't do...so fitting HUGE vented discs will be relatively pointless unless you give them their own dedicated source of cooling air.

    The design of the S3 bumper in particular was bad at cooling the front brakes.

    Also, the Audi stone guard thingies on the inside do a rare job of keeping cooling air out and heat in - best they get binned ASAP...which again means more maintenance by way of inspections.

    The best I have ever studied appear to be vented discs that are able to be force fed to their inner faces, (venting near the hub centre) which will allow the air to be thrown from the inner centre to the outside (near the wheel)..this seems to be the most efficient way to cool the disc...this also is the most efficient at keeping the balljoints and bearings cool.

    The current design of big brakes under big wheels leaves little room for cooling air to be drawn in past the leading edge of the disc...all the more reason why owners MUST pay more attention to correct cooling from the inside.

    The discs in the picture apear to be of this type...not surprising if they are based on / using a Porsche rotor!

    Brakes eh? A science in themselves.
    #16
  18. imported_Stewart
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    imported_Stewart Guest

    [Sep 8, 2005]
    Scotty, look out for me at the Ring this weekend... With a party of Mk5 and Mk4 Golfs (E46 M3 will be with us as well), come and say hello!
    We'll be doing a couple of laps on the Sat tea time session...
    We're going to Sabines for a meal on Sat night if your interested...

    Have a safe journey there!
    #17
  19. recomdos
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    recomdos Member

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    [Sep 8, 2005]
    wow Glen, interesting thoughts there. good stuff /ubbthreads/images/graemlins/smile.gif I'll soon be looking for some new discs and pads and this all makes me even more confuzzled! heh

    Rob /ubbthreads/images/graemlins/smile.gif
    #18

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