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S4 Brake Upgrade

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by GSCollie, Jul 23, 2005.

  1. GSCollie
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    GSCollie Member

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    [Jul 23, 2005]
    Apologies in advance if people feel this is in the wrong forum, but having scoured this site and the net I'm not coming up with any joy in recommendations for my query so here goes......

    Next project is to upgrade disks, pads, calipers and lines front and rear. I see some have used Porsche 996 parts as upgrades but what about Brembo, AP Racing or even RS6 brake set up as an upgrade? /ubbthreads/images/graemlins/noidea.gif

    Any advice would be appreciated as I am likely to take it on track days more often and want a little more bite on standard roads than I have currently before remap, sports cats etc.

    Thanks in advance
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  3. scoTTy
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    scoTTy Active Member

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    [Jul 23, 2005]
    I've got an email into AP Racing at the moment. A few months ago I know they were looking for a B6 S4 development car. I don't know if it's been done or not.
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  4. GSCollie
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    [Jul 23, 2005]
    Thanks gents, I'll E-mail Rich in the meantime but if anything comes of your E-mail ScoTTy I'd be keen to hear.

    I did have a look at Brembo Gran Turismo Brake kit for front and rear but sounds like a computer game than a serious alternative and the cost was reasonable; but I wondered whether it was decent on a day to day commute.
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  5. amurdough
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    amurdough New Member

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    [Jul 29, 2005]
    Those Brembo brakes are very nice, but if you're just looking for a nice day to day set of brakes they might be a little too much. On the other hand, if you're planning on driving hard and taking your car to the limit then the Brembo's are a very good choice!
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  6. scoTTy
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    scoTTy Active Member

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    [Jul 29, 2005]
    I've also got a lead on some good priced Stop-Tech brakes.

    I'll try and get more info.
    #5
  7. dummi
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    dummi smoking a6

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    [Jul 30, 2005]
    i'm looking for some for the rear on a6, have cayennes on the front, but want the rear to share some of the weight, would s4 fit a6 anyone know for sure (Rich?) stoptech told me they'd only do rear if i use their front.
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  8. scoTTy
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    scoTTy Active Member

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    [Jul 30, 2005]
    StopTech are about the only company that seem bothered about brake balancing. I'm seriously considering using them at the moment.

    I wonder how many people out there have fitted huge brakes on the front and actually increased their stopping distance due to the rears doing less than they did. (I can elaborate if you want to get bored!!)
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  9. GSCollie
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    [Jul 31, 2005]
    ScoTTy,

    Have you got any further with AP Racing? I had a look at their website and noticed they have a kit for the B5 S4 but not for the B6 as does everyone else except Brembo if just looking at their respective websites. Also, what's your thoughts on slotted vs drilled? I'm probably going to go for the former if available in whatever manufacturer I opt on.

    The only other thing is to find a local dealer, you southerners seem to have the best deal when it comes to upgrading performance parts; I wonder if they think Geordies are still riding around on their pit ponies......

    I don't get why people would just upgrade fronts except for expense sake, would someone be as kind to explain............? /ubbthreads/images/graemlins/noidea.gif

    I also see that Brembo over the pond are testing an adjustable break balance GT kit and possibly extending it to the GT Junior, that could be useful for track days. /ubbthreads/images/graemlins/smile_smoking.gif

    /ubbthreads/images/graemlins/beerchug.gif
    #8
  10. dummi
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    dummi smoking a6

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    [Jul 31, 2005]
    well put it this way my when you brake all the weight goes to the front and front brakes need to take a high proportion of the weight, rears imo balance it a bit more on say a car your going to throw around offering a bit more control, really you only need upgrade the front, my stopping distance is around 1/2 what it was since just the front upgrade, rear wont do much more to help this but may help keep the car feeling more stable under very heavy braking, as say my fathers jag does, gives a more precise feel not really necessary imo

    but doing rear on its own is akin to pulling the hand brake obviously a no-no
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  11. scoTTy
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    scoTTy Active Member

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    [Jul 31, 2005]
    I said I could elaborate if needed....

    I hope we all agree that maximum retardation is actually limited by the tyres. i.e. most of us have brakes that can lock the wheels already.

    So take the example of a car that is only braking the front wheels. The maximum retardation is limited to the grip given by the two front wheels. If you could get the backs to take part as well then you'd get additional retardation as you're increasing the number of wheels braking. Of course we all know that the fronts do most of the work (due to the weight transfer) so adding read brakes won't half the stopping distance but it will slow you quicker.

    In the same manner, increasing the stopping power of the front brakes can lead to them get to maximum retardation i.e. the front tyres at at the limit of grip, and yet the rears are not braking at their (or the rears tyres) maximum level.

    You can therefore have a situation due to incorrect brake balance where a brake upgrade is not as effective as it could be by balancing it with the rears.

    Of course it all comes down to cost and the difference on the rears will be less than the difference of upgrading the fronts hence making them less cost effective and less appealing.

    I know I should do both. All I have to do it justify it.

    p.s. Nothing yet from AP Racing. I'll chase it and another path on Monday.
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  12. s3bow
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    [Jul 31, 2005]
    You are right. The tyres grip is the defining factor. But, factor in repeated high speed stops, and it makes sense to upgrade. I don't buy the increasing stoppibg distances line though. Most standard Audi brakes will fade after repeated hard use.

    Chris.
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  13. scoTTy
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    scoTTy Active Member

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    [Aug 1, 2005]
    I mainly agree.

    Take two scenarios - track and road

    Track - brakes have many high speed stops and hence OEM are likely to suffer more fade than after market resulting in a Big Brake Kit (BBK) on the frontswould shorten or at least maintain the stopping distance better. (It may not be too stable though and may wish to come around the side)

    Road - In normal use both brakes can lock the front wheels (or activate ABS) and we're therefore at maximum retardation. The car with the BBK may not actually be utilising all of the stopping power of the rear tyres due to the imbalance and hence the stopping distance is extended.

    I've not conducted tests myself. I'm just going on what I've read of tests that have been done. I also think that it'd be quite rare but I can see it happening in some situations.
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  14. dummi
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    dummi smoking a6

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    [Aug 1, 2005]
    worth mentioning is the calliiper design which i think is the main factor the brake efficiency, this is my own opinion since upgrading

    originally i had 2 pot on one side with 320mm discs, good stopping power

    now i have 6 pot 3 on each side and maybe it is just evening in force that allows it to more stopping power to be put on the brake discs

    so this system allows the brakes to be more efficient with bigger pads and discs, less lock ups with wheels. my stopping distance is very much shorter now and abs kicks in less, maybe not half the stopping distance, maybe 2/3's which is still very significant
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  15. scoTTy
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    scoTTy Active Member

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    [Aug 1, 2005]
    I'm not disputing your claims (honestly I'm not) but how do you brake shorter with less abs? Surely the abs only kicks in when the tyres locking and with tyre grip being the limiting factor how does a change in brakes reduce abs and shorten stopping distance? Genuinely puzzled.
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  16. dummi
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    dummi smoking a6

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    [Aug 1, 2005]
    less brake fade and more stopping power every time they are engaged, i guarantee you less stopping distance on that car, tested it along straight before and after, just efficency of the brakes is up and they lock up less, maybe the materials they are made from come into play there. maybe with my old ones i experienced more the brake discs locking against the pads at high temps more? now i experience abs less, probably now when the tyres are the restricting factor, guess what i'm trying to tell you i have noticed is the efficiency of the brakes is up which definently cut stopping distances, hope my thoughts are better explained in that, just give me a buzz if i'm still not clear /ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/smile.gif
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  17. GSCollie
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    GSCollie Member

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    [Aug 2, 2005]
    I would have thought that upgrading both front and rear is the optimum solution. Apologies, I didn't want my original question to sound like I was being a bit thick. I do understand all the principals but rear brakes are there for a reason and if you consider upgrading the fronts I would automatically do the rears as well as they still have a proportion of the weight of the car on them albeit less than normal in heavy braking circumstances and would help with reducing the load on the fronts giving them longer life and retardation / effect in heavy braking situations and therefore less prone to ABS interference.

    I can understand dummi's comments but that only applies with effective brake balancing as I think ScoTTy is getting at. Anyway, we digress........ what set up have you got on your car dummi?

    I am looking into, pad, disk, caliper and line upgrades and therefore also brake fluid. ScoTTy, how are you getting on with AP and StopTech?
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  18. scoTTy
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    [Aug 2, 2005]
    Dummi - You said you had ABS activate more before than now but then you say that the tyres are now the restricting factor. Sorry I'm more confused.

    bbg52 - I'm struggling
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  19. dummi
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    dummi smoking a6

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    [Aug 2, 2005]
    i've upgraded front from 2 pot stock audi to porsche cayenne 6 pot, pagid pads and discs, i guess what i am trying to say is the clamping force is much greater and more effective and the pad material on them is very good

    i think the original brakes were under my expectation and the new sort offer a much more precise effective feel

    i didn't do rears at the time because of the cost and to see what the bias was like, but absolutely agree that f + r is obviously optimum

    also as my car is not putting out enough power to really assess performance of brakes, more it has good stopping power with its weight

    i find my cars wheels used to lock up the discs rather than the tyres as i compare too my current set up i can brake harder and abs does not kick in as much thus i deduce the new brakes are more effective at their job so i can brake for longer without abs and when the braking clamping force is on it has a greater effect due to the bigger clamping force on bigger discs, from what i've read in other posts when i was looking to brake upgrade i can also agree with that brake calliper design is important, from my old brakes having pistons on one side and my new having on both sides there is less sticking of the disc between the pads, like a jarring effect i had on braking perhaps more noticeable due to the weight of the car,

    i think i finally get to my explaination in that last paragraph, i'm just going on what i've experienced since the upgrade
    #18
  20. auroan
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    auroan Active Member

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    [Aug 2, 2005]
    The reason the brake kits are improving already good brakes is not there increased ability to stop the car, as we know braking is the limit of the tire can stand (Kamms circle theory), but the lessoning of time it takes for the brakes to "bite". Thus your stopping distances are reduce because the car is "reacting quicker"

    If you get it wrong like ScoTTy said by over balancing the brake bias, you actually push the tyre past it's limit quicker, thus increasing your braking distance.
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  21. dummi
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    dummi smoking a6

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    [Aug 2, 2005]
    yeah i totally agree what he is saying, two wheels wont brake aswell as four ofcourse, i just gave a relay of my practical experience from the ground up with my brake upgrade which sometimes helps with a different view
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  22. scoTTy
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    scoTTy Active Member

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    [Aug 2, 2005]
    Very interesting. I guess the old brakes could be grabbing and hence activating the ABS whereas the new ones are more progressive. Seems to make sense. Thanks for the extra clarity for my slow mind. /ubbthreads/images/graemlins/crazy.gif
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  23. GSCollie
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    [Aug 2, 2005]
    Dummi, where did you get your brakes upgraded. I'm struggling to find somewhere up in the NE who'll do it, so may have to make the trek down south to get it done. Also, how long does it take to do, a few hours, a day, longer??

    Question for ScoTTy if I may, on the track days you've been on how are the OEM brakes holding out when you are pushing it??

    Also totally unrelated what the f /ubbthreads/images/graemlins/swear.gifk goes on with my posts? Was a regular this morning, now halved in number and I'm a junior again!! Someone trying to tell me my input to the site is pants??
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  24. Kevint
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    [Aug 2, 2005]
    [ QUOTE ]


    Also totally unrelated what the f /ubbthreads/images/graemlins/swear.gifk goes on with my posts? Was a regular this morning, now halved in number and I'm a junior again!! Someone trying to tell me my input to the site is pants??

    [/ QUOTE ]

    Afew days ago the site went down and was rolled back acouple of months, you losts your post count then, along with everyone else.

    Kev.
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  25. GSCollie
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    GSCollie Member

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    [Aug 2, 2005]
    Ah well, s /ubbthreads/images/graemlins/swear.gift happens!
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  26. dummi
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    dummi smoking a6

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    [Aug 2, 2005]
    ScoTTy think my experience would be the usual one for someone without stock high performance, your stock brakes on an s4 i would guess are better, certainly rs models use brembo's.. i wasn't trying to have a go at your mind, more my explaination is poor it took till that last paragraph for me to get it down properly /ubbthreads/images/graemlins/lol.gif

    bbg52 i put the brakes on myself, took a whole saturday until it was too dark to see to fit them on, then on sunday rechecked and re bled using dot 5.1 from halfords, really like that stuff and there is lots of it for the rebleeds.

    if you have a weekend on your hands you should be able to do them, took me the weekend to do 1 pair

    my brakes are the same as the ECS style porkas RichA3 sells and with ecs you can just bolt them straight on, wont take long at all if your familiar with the brakes on your audi
    #25
  27. simon_golf_tt
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    [Aug 3, 2005]
    B6 S4 drivers - if you do end up upgrading your front brakes then why not try selling your OE setup to the B6 A4 community as it goes straight on the A4. It's been done on the US forums. Your OE brakes might not be so good for ~340bhp but I'm sure they will feel awesome in a ~200bhp car. I know I would be interested if the price was right. /ubbthreads/images/graemlins/grin.gif

    Maybe you intended to do this already but thought I'd suggest just in case ! The money can offset the upgrade /ubbthreads/images/graemlins/beerchug.gif
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  28. scoTTy
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    [Aug 3, 2005]
    [ QUOTE ]
    Question for ScoTTy if I may, on the track days you've been on how are the OEM brakes holding out when you are pushing it??

    [/ QUOTE ]
    I'm not being difficult in my response but....if depends how hard you use them. /ubbthreads/images/graemlins/crazy.gif

    On my first trackday in the car I didn't get any fade (Bedford Autodrome) and I thought they were excellant.

    At the Nurburgring I also had no brake fade although they felt just a little soft after one section after a couple of near back to back laps.

    They are actually really good and stop you well. When I first got the car I was raving about how good they are...but they can be bettered.

    I did a track day at Castle Combe and although they lasted a lot better than my old TTs brakes, they did start to go off at the end of a 20-25 minute session. Admittedly I was testing them and braking later and harder as I wanted to see how far I could push them. Normally I have more mechanical sympathy and also aim to be smoother, have the car balanced and settled etc as I go into bends rather than really late heavy braking right up to turn in point. The problem is that after a session like that they haven't fully recovered by the next session and so as the day goes on it gets worse.

    I may still not go for an upgrade. It all depends on costs etc. If I can't get it sorted before September (next 'ring trip) then I may not bother as they are pefectly useable even on trackdays.

    I managed many trackdays in my TT with OEM brakes and never dropped back from the Brembo fitted TTs, S3s etc. You just have to be smoother and drive better,,,,perhaps thats the answer? It'll save me a load as well.

    As yet I'm not 100% committed so I'll see how it goes.

    p.s. If any of you non S4 owners put S4 brakes on then you will be very happy with them as for OEM brakes they are very good. /ubbthreads/images/graemlins/wink.gif
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  29. scoTTy
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    scoTTy Active Member

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    [Aug 3, 2005]
    #28
  30. dummi
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    dummi smoking a6

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    [Aug 3, 2005]
    even more complicated /ubbthreads/images/graemlins/lol.gif

    just chatted to stoptech and they are planning a 2 piston rear brake kit to go with those who already have big up front

    they still sell the 4 wheel bbk 332 up front and 328 at the back with smaller pistons for tuned braking

    can't use the rear part of this kit with normal front bbk as pistons are different sizes so tuned different
    #29
  31. scoTTy
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    scoTTy Active Member

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    [Aug 3, 2005]
    I guess you're referring to a kit for your A6 and not A4s?
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  32. dummi
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    dummi smoking a6

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    [Aug 3, 2005]
    actually thats the s4 b5 base, they only do front for a6 for some reason
    #31
  33. imported_VaulterTim
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    imported_VaulterTim Guest

    [Aug 4, 2005]
    This is an interesting read if you have the time /ubbthreads/images/graemlins/grin.gif Brake Bias Explained


    Explains quite a lot of what you guys have been debating here and it is from one of the best, ECS Tuning.


    Happy reading!

    Tim
    #32
  34. GSCollie
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    [Aug 4, 2005]
    Thanks Tim,

    Just need to find somewhere that will stock and do all the work now. I don't know that I'll need such large brakes because as ScoTTy said previously the OEM brakes are good, I just want a little better bite under my left foot especially as I have to contend with Croft and Knockhill for track days with numerous braking points.

    I know I'm wimping out on DIY but with the car only being 9 months old I'd rather someone who really knows what they're doing fitted it.
    #33
  35. scoTTy
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    scoTTy Active Member

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    [Aug 4, 2005]
    I'm now pondering what to do.

    The Movit kit for mine is £2600 + VAT and fitting as their prices have just gone up.

    EBC don't do pads and disks for hte B6 S4 yet.

    Stop Tech are expensive to bring in (due to shipping over from the US).

    AP Racing currently don't do a kit although I have to talk to them about loaning my car to possibly develop one.

    All in all it's not gonna happen before next weeks trackday or evne my 'ring trip in September....

    although I do still have two options:

    [1] I know of a guy in Belgium who has the Stop Techs
    [2] I know a guy in the US selling his Brembos with Cryo'ed disks.

    ponder ponder...
    #34
  36. imported_VaulterTim
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    imported_VaulterTim Guest

    [Aug 4, 2005]
    What about the ECS kit??? Cayenne 6-pots /ubbthreads/images/graemlins/smile.gif (drool...)
    #35
  37. scoTTy
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    scoTTy Active Member

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    [Aug 5, 2005]
    I've been doing some thinking about it. I;ve looked at the ECS stage 4 kit and it looks good. However I don't spend a load of wonga just for looks. I'm coming to the conclusion that due to the limited number of track days I do (4-6 a year + 3-4days at the 'ring) that I won't really get much value out of a BBK.

    If I was to then I'd feel obliged to at least change the rear disks to match. Partially coz I think it would look weird otherwise and secondly to ensure the balance remains. This pushes the price up and being totally honest I think I can spend the money in better ways.

    I'm now pursueing the thought of the ECS OE 2 part disks. I could get these (front and back) and since I'm about to renew by pads anyway it would be much cheaper and give me the extra cooling that I was after. As I've always said the S4 brakes are really good. I've just found that by the end of a few track sessions they can start to go off. If I get these new disks and then it will be good enough. For this I'm looking at around £1k which is much easier to justify.

    Still not 100% decided though!
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  38. GSCollie
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    [Aug 6, 2005]
    ScoTTY,

    Have you got a link for the ECS OE 2 part disks. Thinking about it unless a pot of cash came my way I can't afford any more than around £1K either, especially when the other half is expecting me to make an honest woman of her by going down on one knee and popping the question.

    Hmmm, diamond ring...brake kit....diamond ring.... brake kit.....easy life.... diamond ring it is then!!
    #37
  39. dummi
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    dummi smoking a6

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    [Aug 6, 2005]
    pm RichA3Turbo to sort you out, he's ecs distributor in the uk

    i think the cayenne brakes are 1400 with 2 piece discs, pads, callipers, braided hoses, brake fluid if you DIY
    #38
  40. imported_VaulterTim
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    imported_VaulterTim Guest

  41. scoTTy
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    scoTTy Active Member

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    [Aug 6, 2005]
    I've been emailing Richard at JBR. Since he is supply only AMD are currently talking to him about sourcing them from him and giving me a fitted price.
    #40

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