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a3 brake upgrade

Discussion in 'Tuning' started by lankyandy, Sep 20, 2005.

  1. lankyandy
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    lankyandy New Member

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    i have a 2006 a3 and have noticed that amd do the porsche upgrade kit for the front and ventilated on the rear.has anyone had this done?i dont find the brakes lacking in power but i am planing upgrading the turbo and then some track work so they may be needed for that.any advice on improoving brakes greatly appreciated
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  2. smoothy
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    smoothy Member

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    Its been discussed a fair bit, do a search u will find lots of info, thats what I did!

    Most people go for the brembo kit as its good value and the porker ones are made by brembo anyway.

    Also some of the bigger porsche kits require a larger Master cylinder!

    Porsche for bling! Brembo for a value bit of kit that works.

    Where's me credit card! /ubbthreads/images/graemlins/grin.gif
    #2
  3. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [ QUOTE ]
    Its been discussed a fair bit, do a search u will find lots of info, thats what I did!

    Most people go for the brembo kit as its good value and the porker ones are made by brembo anyway.

    Also some of the bigger porsche kits require a larger Master cylinder!

    Porsche for bling! Brembo for a value bit of kit that works.

    Where's me credit card! /ubbthreads/images/graemlins/grin.gif

    [/ QUOTE ]

    We've got R32 customer running ECS Stage 5 (Porsche Cayenne 6-pot calipers) and the master cylinder manages just fine. If it can handle those calipers, it can handle any!!

    Rich
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  4. Ess_Three
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    Ess_Three Active Member

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    [ QUOTE ]

    We've got R32 customer running ECS Stage 5 (Porsche Cayenne 6-pot calipers) and the master cylinder manages just fine. If it can handle those calipers, it can handle any!!
    Rich

    [/ QUOTE ]

    Now then Rich...this depends on how close you class 'handle' to 'works perfectly'

    I'm sure an S3 or R32 master cylinder will quite happily move enough fluid to make the brakes work...but it it moving enough to make them work efficiently?

    I've been caught / fooled by this in the past...where fitting big brakes gives brakes that work...but:
    That need more pressure to get an effective stop
    That need a longer push of the pedal to get an effective stop
    That are harder to modulate under heavy braking
    That imbalance the car as they proportionally send more fluid to the rear than front...making the ABS work harder to keep the car stable - not ideal.

    My experience of pressing the pedal of a Porsche equipped S3 is that the pedal had a fairly long travel...far longer than in a 911 for example, where the pedal has approx 5mm of travel before full braking is felt!

    So, I know that various master cylinders will work with various callipers...but there is no way on this earth that Cayenne 6 pots are moved efficiently by a master cylinder designed for 2 x sliding callipers or even R32 twin pots...
    I'm sure a check of ETKA vs PET would confirm this.

    Personally, I'd be asking questions on master cylinder matching before I spent cash on a hotch-potch kit.

    A simple look at the size of Porsche 'pots' will give you an indication that a VAG is likely to be not perfect for the application.
    Now, I'm not saying that they won't work...they do.
    But I am saying that I'd want to be assured that the master cylinder volume was matched to calliper volume to ensure I lost no 'feel' through the pedal...

    But hey, in the world of 'bling' who cares about feel, pedal movement, fluid displacement vs pressure etc...if they look good? /ubbthreads/images/graemlins/tongue.gif

    Personally, I'd give up some of the 'look' for brakes that offered an increase in feel and feedback - something the standard stuff doesn't offer...and something the Brembo kit does...
    #4
  5. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [ QUOTE ]
    [ QUOTE ]

    We've got R32 customer running ECS Stage 5 (Porsche Cayenne 6-pot calipers) and the master cylinder manages just fine. If it can handle those calipers, it can handle any!!
    Rich

    [/ QUOTE ]

    Now then Rich...this depends on how close you class 'handle' to 'works perfectly'

    I'm sure an S3 or R32 master cylinder will quite happily move enough fluid to make the brakes work...but it it moving enough to make them work efficiently?

    I've been caught / fooled by this in the past...where fitting big brakes gives brakes that work...but:
    That need more pressure to get an effective stop
    That need a longer push of the pedal to get an effective stop
    That are harder to modulate under heavy braking
    That imbalance the car as they proportionally send more fluid to the rear than front...making the ABS work harder to keep the car stable - not ideal.

    My experience of pressing the pedal of a Porsche equipped S3 is that the pedal had a fairly long travel...far longer than in a 911 for example, where the pedal has approx 5mm of travel before full braking is felt!

    So, I know that various master cylinders will work with various callipers...but there is no way on this earth that Cayenne 6 pots are moved efficiently by a master cylinder designed for 2 x sliding callipers or even R32 twin pots...
    I'm sure a check of ETKA vs PET would confirm this.

    Personally, I'd be asking questions on master cylinder matching before I spent cash on a hotch-potch kit.

    A simple look at the size of Porsche 'pots' will give you an indication that a VAG is likely to be not perfect for the application.
    Now, I'm not saying that they won't work...they do.
    But I am saying that I'd want to be assured that the master cylinder volume was matched to calliper volume to ensure I lost no 'feel' through the pedal...

    But hey, in the world of 'bling' who cares about feel, pedal movement, fluid displacement vs pressure etc...if they look good? /ubbthreads/images/graemlins/tongue.gif

    Personally, I'd give up some of the 'look' for brakes that offered an increase in feel and feedback - something the standard stuff doesn't offer...and something the Brembo kit does...

    [/ QUOTE ]

    Not having tried them myself, it is something that i asked Jon Watts @ VAG Tech as he fitted to his R32. He said they are all round a great setup and is more than happy with the results... The size, as i just said, was something i did wonder about... If the pedal would go all the way to the floor before anything happened, but this is not the case and i've been told by several customers how impressed with the setup they are. But as i say, not tried them for myself...yet.

    Now, although they are massive, and 6-pots, the pistons are not large...Quite small in fact. We've got a set of these in stock and also a set of big reds so i will measure the piston area and see how they compare.

    Rich
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  6. Ess_Three
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    Ess_Three Active Member

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    [ QUOTE ]

    The size, as i just said, was something i did wonder about... If the pedal would go all the way to the floor before anything happened, but this is not the case and i've been told by several customers how impressed with the setup they are.


    [/ QUOTE ]

    Fair play...

    But, the issue of master cylinder suitability is a concern.

    Not just for ECS kits mind...

    Brembo sell the GT kit for all 5 stud VAG cars...Mk3 Golf GTI/VR6, Mk4 GTI etc, A3, S3 etc...

    A Mk3 GTI has a master cylinder size of 22.2mm
    A Mk4 GTI / A3 / S3 has a master cylinder size of 23.8.

    Not a lot, 1.6mm...but in area, a fair proportion larger.

    And people sell that kit for all cars...
    Now the Leon Cupra R has a 23.8 MS, so they should be perfectly suited to all Mk4 platform cars...A3/S3/TT etc...
    Not so the Mk3...you'll loose feel, gain pedal travel and loose modualtion.

    A look at the Porsche PET system reveals that earlier 911s have different master cylinders to later - although sizes are harder to find (I failed)
    Early (996) 911s have one size master cylinder...later 'facelift' cars, another...and GT3s, GT2s, Turbos and C4Ss a different one again to take account of the larger callipers all round.
    I seem to remember the C4S MS is 25mm (although couldn't find proof)

    The Cayenne is different again, presumably larger due to it's larger callipers and higher mass it's stopping.

    What I'm getting at is that there is no way a calliper set designed for a 25mm MS will do a perfect job when being fed by a 22.2mm or 23.8mm MS...

    ECS claim the 6 pot kit (Stage 5) is suitable for TTs, S3s, A3s and Mk3s...sorry, but I beg to differ.
    Will they work...yes.
    Will they be efficient and work to the best of their ability? No chance...

    This theory is proven by my running S3/TT front callipers on my Mk3. Callipers designed for a 23.8mm MS fed by a 22.2mm MS...poor feel, more pedal travel etc...I shall be replacing them with the original GTI callipers (part numbers were different, although physically the same to look at!) as soon as I've re-furbished them!


    Basically...what I'd like to know is:
    If fitting Porsche callipers to a non-Porsche is running them on a smaller master cylinder...then you are selling yourself short of braking force - they could perform better.
    ...and if they perform less good than they could...are they any better than the properly matched Brembo GT kit?
    ...if not...why spend the extra for Porsche writing on the side of a Brembo kit?

    ...which brings us full circle, and straight back at the door of 'bling', does it not? /ubbthreads/images/graemlins/wink.gif
    #6
  7. smoothy
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    smoothy Member

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    So as far as I can tell there are two options from brembo

    <ul type="square"> [*]Brembo GT [*]Brembo GT Jr [/list]

    I understand that the GT kit has two peice discs and te JR kit uses Cupra R one peice items. Am I on the right lines here?

    By the way good thread! /ubbthreads/images/graemlins/jump.gif
    #7
  8. Ess_Three
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    Ess_Three Active Member

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    [ QUOTE ]

    I understand that the GT kit has two peice discs and te JR kit uses Cupra R one peice items. Am I on the right lines here?


    [/ QUOTE ]

    I wouldn't go for the 2pc discs...not in Aberdeenshire anyway.
    You have to pay close attention to multi-piece discs to stop them seizing up and causing additional braking problems.
    David R had multi-piece discs on his uprated Stoptech S4 kit...and now runs plain Cupra R discs of the single piece variety...with devastating effect on road or track.

    The single piece discs are relatively cherap and readily available...

    So I see no need for the more expensive kit over the Jr kit...except for the bling factor points associated with it.
    The performance of the Jr kit has been proven time and time again, road and track...
    There are very few cars outbrake David R in his S3 round Knockhill...all day long, no fade...no fuss. And all on plain Cupra R discs and Brembo GT callipers with slightly better friction material.
    #8
  9. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [ QUOTE ]
    [ QUOTE ]

    The size, as i just said, was something i did wonder about... If the pedal would go all the way to the floor before anything happened, but this is not the case and i've been told by several customers how impressed with the setup they are.


    [/ QUOTE ]

    Fair play...

    But, the issue of master cylinder suitability is a concern.

    Not just for ECS kits mind...

    Brembo sell the GT kit for all 5 stud VAG cars...Mk3 Golf GTI/VR6, Mk4 GTI etc, A3, S3 etc...

    A Mk3 GTI has a master cylinder size of 22.2mm
    A Mk4 GTI / A3 / S3 has a master cylinder size of 23.8.

    Not a lot, 1.6mm...but in area, a fair proportion larger.

    And people sell that kit for all cars...
    Now the Leon Cupra R has a 23.8 MS, so they should be perfectly suited to all Mk4 platform cars...A3/S3/TT etc...
    Not so the Mk3...you'll loose feel, gain pedal travel and loose modualtion.

    A look at the Porsche PET system reveals that earlier 911s have different master cylinders to later - although sizes are harder to find (I failed)
    Early (996) 911s have one size master cylinder...later 'facelift' cars, another...and GT3s, GT2s, Turbos and C4Ss a different one again to take account of the larger callipers all round.
    I seem to remember the C4S MS is 25mm (although couldn't find proof)

    The Cayenne is different again, presumably larger due to it's larger callipers and higher mass it's stopping.

    What I'm getting at is that there is no way a calliper set designed for a 25mm MS will do a perfect job when being fed by a 22.2mm or 23.8mm MS...

    ECS claim the 6 pot kit (Stage 5) is suitable for TTs, S3s, A3s and Mk3s...sorry, but I beg to differ.
    Will they work...yes.
    Will they be efficient and work to the best of their ability? No chance...

    This theory is proven by my running S3/TT front callipers on my Mk3. Callipers designed for a 23.8mm MS fed by a 22.2mm MS...poor feel, more pedal travel etc...I shall be replacing them with the original GTI callipers (part numbers were different, although physically the same to look at!) as soon as I've re-furbished them!


    Basically...what I'd like to know is:
    If fitting Porsche callipers to a non-Porsche is running them on a smaller master cylinder...then you are selling yourself short of braking force - they could perform better.
    ...and if they perform less good than they could...are they any better than the properly matched Brembo GT kit?
    ...if not...why spend the extra for Porsche writing on the side of a Brembo kit?

    ...which brings us full circle, and straight back at the door of 'bling', does it not? /ubbthreads/images/graemlins/wink.gif

    [/ QUOTE ]

    I agree to the point made about them not working to their full potential, but there are otehr things to consider other than the caliper itself and force being exerted on the disc.
    1) Swept area
    2) disc size

    The Cayenne pads are the size of a Brembo GT/ECS 2v2 caliper! they are massive! Swept area is a minimum of twice the size of the GT kit/2v2 kits. Now the discs are 358mm as opposed to 322(?)mm of the brembo. This again, will have a considerable effect on braking force. Now to me, the calipers would have to be seriously inefficient to only match the performance of the GT kit in my opinion. Fair enough the MC is smaller than it probably should be, but how much of an effect, in real terms, does it have? Ok the pedal will have to be pressed a bit further for the brakes to start working, but they will require less force to work as well as the OE setup.... of course pedal feel will be affected, but from what i have heard, not a great deal.
    #9
  10. smoothy
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    smoothy Member

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    I see JBR do the kit here

    My question is do I have to buy the calipers and brackets with thoughs discs and pads or can I use any cupra R discs. Also How do you spec pads for them are they also cupra R pads?
    #10
  11. lankyandy
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    lankyandy New Member

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    can you increase the size of the master cylinder?wot about front rear brake balance with upgrading the fronts and not rears?thanks for help so far
    #11
  12. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [ QUOTE ]
    can you increase the size of the master cylinder?wot about front rear brake balance with upgrading the fronts and not rears?thanks for help so far

    [/ QUOTE ]

    In that respect, we also do a rear upgrade converting 239/256 discs to 308mm. Its a nice upgrade that brings the balance back into line and makes the car much more stable under heavy braking

    Rich
    #12
  13. Ess_Three
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    Ess_Three Active Member

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    [ QUOTE ]

    I agree to the point made about them not working to their full potential, but there are otehr things to consider other than the caliper itself and force being exerted on the disc.
    1) Swept area
    2) disc size


    [/ QUOTE ]

    True...
    And others such as:
    Disc thickness (heat dissipation)
    Piston Force (pressure from the friction material on the disc surface)
    Unsprung weight - and this is the big one for me!

    [ QUOTE ]

    The Cayenne pads are the size of a Brembo GT/ECS 2v2 caliper! they are massive! Swept area is a minimum of twice the size of the GT kit/2v2 kits. Now the discs are 358mm as opposed to 322(?)mm of the brembo.


    [/ QUOTE ]

    Indeed...and look at the size of the chunks of metal you have bouncing up and down at the end if your driveshafts!

    My opinion - not shared by all - is that I'd have the smallest brakes fitted that will do the job...the lightest callipers, lightest disc (reliably light)and best friction material I can get...

    This philosophy yields better handling (less unsprung weight) better turn is (less gyroscope effect) and as long as the pad type can transfer the braking force efficiently to the disc surface, and the disc can dissipate the heat, then the smaller the set up the better.

    This has the knock on effect of being able to run smaller diameter and width wheels which again, will save weight.


    [ QUOTE ]

    This again, will have a considerable effect on braking force. Now to me, the calipers would have to be seriously inefficient to only match the performance of the GT kit in my opinion.


    [/ QUOTE ]

    But if your applied force is lower (less fluid able to be moved by the master cylinder per pedal stroke) then the force excerted will not be as high as on the relevant Porsche model...and unlikely to be far removed from the force applied to the Brembo GT kit with a correctly sized master cylinder...and you keep the feel of the pedal with the smaller callipers.

    I reckon this is the case...


    [ QUOTE ]

    Fair enough the MC is smaller than it probably should be, but how much of an effect, in real terms, does it have?


    [/ QUOTE ]

    Lots...

    As I have said, I have lost all feel through the brake pedal, gained pedal travel and lost modulation when fitting callipers designed for a 1.6mm larger master cylinder.
    This with larger discs (312mm vs 288mm)
    Not a lot of difference...but a distinct degradation of braking feel...braking effort is probably higher when you jump on the pedal - although this could be down to new callipers vs old seized up callipers!

    Maybe I'm more demanding and less likely to accept compromises...but I'm not happy with the pedal feel...and I'll be going back to the correct callipers soon.


    [ QUOTE ]

    Ok the pedal will have to be pressed a bit further for the brakes to start working, but they will require less force to work as well as the OE setup....


    [/ QUOTE ]

    This I accept...but if your brake pedal is now too far away to heel-toe neatly, then you are not as smooth on the brakes nor as quick point to point.


    [ QUOTE ]

    of course pedal feel will be affected, but from what i have heard, not a great deal.

    [/ QUOTE ]

    This again comes back to the sacrafices the owner is perpared to make...pedal feel to me is more important than outright braking force as its easier to brake right to the ABS activation point if you have feel and feedback through the pedal.
    The Brembo GT kit will lock the front wheels at 100 with a decent shove of the pedal and go all day without fade on the track...so there is enough outright braking effort to make me happy...I'd be happy with that performance and decent (better) pedal feel and feedback.
    #13

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